Long-Sheng Zheng

Charlène Férard

Phannarath Phansavath

Virginie Ratovelomanana- Vidal

Rhodium-Mediated Asymmetric Transfer Hydrogenation: a Diastereo-and Enantioselective Synthesis of syn--Amido -Hydroxy Esters

The preparation of syn -benzoylamido -hydroxy esters through asymmetric transfer hydrogenation (ATH) with a tethered Rh(III)-DPEN complex via dynamic kinetic resolution (DKR) has been developed for the first time starting from -benzoylamido -keto esters. A variety of -benzoylamido -keto esters were converted under mild conditions into the corresponding syn -benzoylamino -hydroxy esters with high yields (up to 98%) and diastereomeric ratios (up to >99:1 dr) as well as excellent enantioselectivities (up to >99% ee).

Because enantiomerically pure -amino alcohols bearing two contiguous stereocenters are valuable building blocks in natural products and pharmaceuticals, and because they can be used as ligands in asymmetric catalysis, an efficient synthesis of these scaffolds is highly desirable. A straightforward and atom-economical access to such compounds involves the dynamic kinetic resolution (DKR) of racemic -amino -keto ester derivatives that can be performed through either asymmetric hydrogenation (AH) or asymmetric transfer hydrogenation (ATH), to obtain the syn or anti reduced products. [START_REF]For selected reviews on DKR through AH/ATH[END_REF] However, although the DKR of amido -keto esters through asymmetric hydrogenation is now well established, the asymmetric transfer hydrogenation of these compounds is much less documented. Previous work in this field only focused on -keto esters that were substituted with carbamate, 2,2-dichloro N-acetamido or amino hydrochloride functional groups in the -position to access the anti amino alcohol derivatives using either ruthenium 2-8 or rhodium 9 complexes (Scheme 1, previous work). On the other hand, scarce examples of the production of the syn compounds through Ru-catalyzed ATH have been described so far for N-diprotected compounds. 5a,10,11 We have previously observed this reversal of diastereoselectivity from anti to syn Scheme 1 ATH of -amino -keto ester derivatives in the Ru- 7 or Rh-mediated 9 ATH of -amino -keto ester hydrochlorides, bearing thienyl or furyl substituents on the ketone functional group. These results clearly indicate that the stereochemical outcome of the ATH of these -amino -keto ester derivatives is highly dependent on the nature of the amino group as well as on the ketone substituent. As part of an ongoing program aimed at developing efficient methods for the asymmetric reduction of functionalized ketones, 12 we report herein an unprecedented syn diastereoselectivity obtained in the Rh-catalyzed DKR/ATH of N-monoprotected amino -keto esters, in this case, -benzoylamino -keto esters (Scheme 1, this work). The novelty of this study resides in the use of a rhodium complex for the ATH-DKR of Nmonoprotected -amino -keto esters to access the corresponding syn products, as opposed to the work described by Wang and coworkers, 11 which involved the Ru-catalyzed ATH of N-diprotected compounds and for which rhodium and iridium complexes were inefficient.

We started our study with the racemic methyl 2-benzoylamino-3-oxo-3-phenylpropanoate 1a as the standard substrate (Table 1). The initial asymmetric transfer hydrogenation experiments were carried out in CH2Cl2 at 30 °C using ruthenium complexes (R,R)-A, (S,S)-B and (R,R)-C in the presence of a 5:2 HCO2H/Et3N azeotropic mixture as the hydrogen source, and afforded the corresponding anti amino alcohol derivatives the major isomers albeit with low enantiomeric excesses (Table 1, entries 1-3). The sense of diastereoselectivity observed here was in agreement with the results reported previously for the ruthenium-catalyzed ATH of the parent -N-Boc or -N-Cbz keto ester compounds. To our surprise however, we found that with the tethered rhodium complex (R,R)-D, 13,14 the reaction proceeded smoothly within 5 h to deliver the reduced syn product (R,S)-2a in 90% yield with a good 86:14 dr and an excellent enantiomeric excess of >99% for the syn isomer (Table 1, entry 4). The absolute configuration of the reduced product 2a was assigned as (2R,3S) by converting the diastereomerically pure syn 2a into the known (1S,2S)-2-benzoylamino-1-phenylpropane-1,3-diol and comparing the optical rotation value with the reported data ([α] 20 = +80.1 (c 1.0, EtOH), lit.: [START_REF] Zhang | [END_REF] [α] +94.6 (c 1.0, EtOH)). [START_REF]The absolute configuration of 2a was further confirmed by comparison with authentic samples of compounds (2R,3S)-2a and (2S,3R)-2a (prepared by ruthenium-catalyzed AH of rac-1a with [RuCl((R)-SYNPHOS) (µ-Cl)[END_REF] To our knowledge, this reversal of diastereoselectivity from anti to syn provided by the use of a Rh complex has never been reported to date for the ATH of Nmonoprotected -amino -keto esters. The use of other solvents under otherwise identical conditions afforded similar results in terms of yields and stereoselectivities although the reaction time was longer in THF and i-PrOH (Table 1, entries 5-7). The neat reaction also led to an 86:14 dr and >99% ee (Table 1, entry 8). The stereochemical outcome of the transfer hydrogenation reaction was not altered by switching from (R,R)- [START_REF] Zheng | [END_REF] bearing respectively, methyl, trifluoromethyl or fluoro groups on the aryl ring, even though the reactions required more time (Table 1, entries 9-11). Accordingly, we selected complex (R,R)-D as the pre-catalyst and CH2Cl2 as the solvent for further studies (Table 2). Performing the reaction at 30 °C with a catalyst loading of 0.1 mol% instead of 0.5 mol% resulted only in an extended reaction time without any noticeable effect on either the yield or stereoselectivity (Table 2, entries 1-2), whereas using a 1:1 HCO2H/Et3N azeotropic mixture rather than the 5:2 system led to incomplete conversion after 24 h of reaction (Table 2, entry 3). The temperature effect was then investigated, and the reaction was run at 18 °C, affording a slightly higher diastereomeric ratio of 89:11 (Table 2, entry 4). A satisfying 92:8 dr was attained at a temperature of 0 °C after either 47 h (Table 2, entry 5) or 94 h with a catalyst loading of 0.2 mol% (Table 2, entry 6). Finally, maintaining a 0.5 mol% catalyst loading, a variation of the initial concentration of -amido keto ester from 0.2 to 0.4 and 0.5 M showed a decrease of the reaction time from 47 h to 34 h and 28 h, respectively (Table 2, entries 5 and 7-8). Accordingly, the optimized reaction conditions were set as follows: 0.5 mol% of (R,R)-D, a 5:2 HCO2H/Et3N azeotropic mixture as the hydrogen source, CH2Cl2 as the solvent (0.5 M), and a reaction temperature of 0 °C. With these conditions in hand, we next investigated the scope of the reaction and a series of variously substituted benzoylamino -keto esters were subjected to the ATH.

D to (R,R)-E, (R,R)-F or (R,R)-G
Compounds bearing substituted phenyl groups on the ketone functional group generally gave the corresponding reduced syn the anti compound as the major isomer (syn/anti 13:87) albeit with a low enantiomeric excess (52% ee), whereas the syn

9/2i

OH O OMe isomer was produced in >99% ee (Table 3, entry 10). On the other hand, heteroaryl ketones afforded excellent levels of diastereo-and enantioinductions and the reduced compounds were obtained in very good yields with the exception of compound 1l, which produced 2l in 87:13 dr and 96% ee (Table 3, entries 11-15). Furthermore, for the amido ester 1o bearing a thienyl substituent on the ketone, no temperature effect was observed because the reaction could be carried out at 30 °C within only 1 h without any alteration of the dr or ee (Table 3, entries 15-16). In addition, the reduction of 1o was efficiently performed on gram-scale demonstrating the usefulness of this method. The substrate scope was then expanded to -amido -keto esters containing an alkyl ketone. For these compounds, the reduced syn products were obtained with lower diastereomeric ratios while the ee remained >99% (Table 3, entries 17-18). As for the sterically demanding substrate 1j, a reversal of diastereoselectivity was observed as well, with the amido ester 1r having an isopropyl substituent on the ketone. This time the anti isomer was formed with a very high level of diastereo-and enantioinductions albeit after a prolonged reaction time of 10 days ( 10 days at 0 °C (Table 3, entry 21) or in only 24 h at 30 °C (Table 3, entry 22).

In summary, the rhodium-catalyzed asymmetric transfer hydrogenation of -amido -keto esters via DKR appears to be an efficient tool for the synthesis of syn -benzoylamido hydroxy esters, which until now were not directly attainable through ATH. The reaction proceeded under mild conditions using a low catalyst loading with tolerance for a diverse set of functional groups, delivering the reduced compounds in good yields, high diastereomeric ratios, and excellent enantioselectivities for a wide range of substrates. Furthermore, the usefulness of this method was demonstrated by the efficient gram-scale reduction of 1o.

a 1 H

 1 Conditions: 0.8 mmol of 1, 0.5 mol% of (R,R)-D, 134 L of HCO2H/Et3N (5:2) in 1.6 mL of CH2Cl2 at 0 °C. Complete conversions except for compounds 1j and 1r for which 73-82% conv. were obtained.b Determined by NMR of the crude product. c Determined by SFC or HPLC analysis.d Reaction carried out at 30 °C.

Table 1

 1 Catalyst and solvent screening a

	1	A	CH2Cl2	96	96	15:85	28 d
	2	B	CH2Cl2 e	7	95	10:90	36 d
	3	C	CH2Cl2 e	9	94	8:92	25 d
	4	D	CH2Cl2	5	90	86:14	>99
	5	D	CH3CN	4.5	86	87:13	>99
	6
	7
	8 f
	9	E	CH2Cl2	7	89	86:14	>99
	10	F	CH2Cl2	7	88	86:14	>99
	11 f	G	-	20	93	84:16	>99

a Conditions: 0.8 mmol of 1a, 0.5 mol% of precatalyst, 134 L of HCO2H/Et3N (5:2) in 4 mL of solvent at 30 °C. Complete conversions in all cases. b Determined by 1 H NMR of the crude product.

c Determined by SFC analysis. d ee of the anti compound. e 1.6 mL of solvent was used.

f Neat reaction.

Table 2

 2 Catalyst loading and temperature screening a Determined by 1 H NMR of the crude product. d Determined by SFC analysis. e 1:1 mixture of HCO2H/Et3N used. f 64% conversion obtained under these conditions.

	entry	catalyst (mol %)	c b	temp (°C)	time (h)	yield (%)	dr (syn/anti) c	eesyn (%) d
	1	0.5	0.2	30	5	90	86:14	>99
	2	0.1	0.2	30	23	91	86:14	>99
	3 e	0.5	0.2	30	24	61 f	86:14	>99
	4	0.5	0.2	18	22	87	89:11	>99
	5	0.5	0.2	0	47	93	92:8	>99
	6	0.2	0.2	0	94	73	92:8	>99
	7	0.5	0.4	0	34	94	92:8	>99
	8	0.5	0.5	0	28	93	92:8	>99
	a Conditions: 0.8 mmol of 1a, respective mol% of (R,R)-D, 134 L of HCO2H/Et3N (5:2) in 1.6-4.0 mL of CH2Cl2. Complete conversions except where indicated.

b Initial concentration of -amido -keto ester. c

Please do not adjust margins

Table 3

 3 Substrate scope a

	5/2e		e
	MeO
	6/2f	OH	O
	O		OMe

OMe substituent on the ketone, which delivered in moderate yield

Table 3

 3 Synthesis, 2016, 48, 2523. 2 M. Perez, P.-G. Echeverria, E. Martinez-Arripe, M. Ez Zoubir, R. Touati, Z. Zhang, J.-P. Genêt, P. Phansavath, T. Ayad, V. Ratovelomanana-Vidal, Eur. J. Org. Chem., 2015, 5949. 3 X. Wang, L. Xu, L. Yan, H. Wang, S. Han, Y. Wu, F. Chen, Tetrahedron, 2016, 72, 1787. 4 L. H. Bourdon, D. J. Fairfax, G. S. Martin, C. J. Mathison, P. Zhichkin, Tetrahedron: Asymmetry, 2004, 15, 3485. 5 (a) B. Seashore-Ludlow, P. Villo, C. Häcker, P. Somfai, Org.

				NHCOPh
	14/2n	O	OH	O	OMe
			NHCOPh
	15/2o 16/2o	S	OH	O	OMe
			NHCOPh
	17/2p		OH	O
					OMe
				NHCOPh
	18/2q		OH	O
	, entry 19), which	Ph			OMe
	could be reduced to 92 h by working at 30 °C with no loss of			NHCOPh
	stereoselectivity (Table 3, entry 20). Finally, the Rh-catalyzed
	ATH of substrate 1s having an alkyne residue proceeded with
	near-perfect diastereo-and enantioselectivities in either
	do not adjust margins

OH O OMe (j) Y. Hamada, Chem. Rec., 2014, 14, 235; (k) F. Foubelo, C. Nájera, M. Yus, Tetrahedron: Asymmetry, 2015, 26, 769; (l) P.-G. Echeverria, T. Ayad, P. Phansavath, V. Ratovelomananae 22/2s d Vidal, Lett., 2010, 12, 5274; (b) B. Seashore-Ludlow, F. Saint-Dizier, P. Somfai, Org. Lett., 2012, 14, 6334; (c) B. Seashore-Ludlow, P. Villo, P. Somfai, Chem. Eur. J., 2012, 18, 7219.

This work was supported by the Ministère de l'Education Nationale, de l'Enseignement Supérieur et de la Recherche (MENESR) and the Centre National de la Recherche Scientifique (CNRS). We gratefully acknowledge the China Scholarship Council (CSC) for a grant to L.-S. Z. We would like to thank L.-M. Chamoreau and G. Gontard for the X-ray analysis. This manuscript is dedicated to Prof. Miguel Yus on the occasion of his 70 th birthday.

Conflicts of interest

There are no conflicts declare.

Notes and references


Muge Ozman

Cédric Gossart
email: cedric.gossart@imt-bs.eu.

Nicolas Jullien

International Review on Public and Nonprofit Marketing Do occupations matter in motivations to volunteer?

Keywords: volunteering, motivations, occupations, digital platforms, VFI volunteering, motivations, occupations, digital platforms, VFI

People are largely heterogeneous when it comes to their motivations to volunteer. Previous research explained this heterogeneity by individual predispositions and contextual factors. In this paper, we investigate the extent to which peoples' occupations can explain differences in their volunteering motivations. Our empirical analysis relies upon 7,725 open texts written by volunteers living in France about why they want to volunteer. Our results reveal that providing resources and skills is a significant motivation to volunteer all occupations combined. However, altruistic and social motives differ between occupations. After eliciting these results for each occupation, we discuss their implications for NPO's volunteer management.

Introduction

Volunteering is a form of social action that is both good in intention and consequence, and an important dimension of civic life in many countries. Previous literature has shown that different motivations drive volunteering [START_REF] Clary | Understanding and assessing the motivations of volunteers: A functional approach[END_REF][START_REF] Snyder | The functional approach to volunteerism[END_REF], which are shaped by intrinsic characteristics like age or personality [START_REF] Hopkins | Young people's motivations for undertaking voluntary work[END_REF][START_REF] Snyder | Volunteerism: Social issues perspectives and social policy implications[END_REF], social context [START_REF] Stukas | Volunteerism and community involvement: Antecedents, experiences, and consequences for the person and the situation[END_REF][START_REF] Enjolras | Explaining the varieties of volunteering in Europe: A capability approach[END_REF][START_REF] Gil-Lacruz | Individual and social factors in volunteering participation rates in Europe[END_REF], and by acquired characteristics like education or status [START_REF] Gage | Volunteer motivations and constraints among college students[END_REF][START_REF] Marta | Volunteerism during young Adulthood: An Italian investigation into motivational patterns[END_REF]. Despite a rich literature analyzing why people differ in these motivations, there is limited research on the role of occupations [START_REF] Marshall | Good jobs, good deeds: The gender-specific influences of job characteristics on volunteering[END_REF][START_REF] Webb | Do occupational group members vary in volunteering activity?[END_REF][START_REF] Rodell | Finding meaning through volunteering: Why do employees volunteer and what does it mean for their jobs?[END_REF]Lampert and Rutherford, 2020). Occupations can influence people's willingness to volunteer, because sharing similar work roles and cultures can lead to adopt similar norms and behaviours, both in organizational [START_REF] Kwantes | Do occupational groups vary in expressed organizational culture preferences? A study of six occupations in the United States[END_REF][START_REF] Wenger | Communities of practice: The organizational frontier[END_REF] and individual activities [START_REF] Lambert | Occupational inequalities in volunteering participation: Using detailed data on jobs to explore the influence of habits and circumstances[END_REF][START_REF] Webb | Do occupational group members vary in volunteering activity?[END_REF]Wilson & Musick, 1997a;[START_REF] Wilson | Volunteering[END_REF][START_REF] Crawford | Understanding the mobilization of professionals[END_REF]. However, with some exceptions empirical research in this area has remained scant (Wilson & Musick, 1997a;[START_REF] Wilson | Volunteering[END_REF]Grant, 2012). Moreover, while studies have analysed the role of occupations in terms of the level of volunteering, to our knowledge no research exists on the extent to which occupations could lead to differences in specific volunteering motivations. Based on these, our research question can be formulated as follows: are occupations of volunteers associated with their motivations to volunteer? If yes, which motivations are significant, and which are not, for different occupations?

In addition to contributing to the literature on volunteering motivations, this research question is important to address because we expect the results to be useful for practitioners dealing with the management of volunteering programs. Volunteer recruitment processes have always been a significant challenge for nonprofit organisations (NPOs) (Nesbit et al., 2017), but especially in the last decade NPOs have experienced difficulties in recruiting and sustaining volunteers [START_REF] Huang | Encouraging volunteering in nonprofit organizations: The role of organizational inclusion and volunteer need satisfaction[END_REF][START_REF] Hyde | Episodic volunteering and retention: An integrated theoretical approach[END_REF]. Satisfying volunteers' initial motivations can address such difficulties by increasing the quality of volunteers' work and their attachment to the organization [START_REF] Brudney | Designing and managing volunteer programs[END_REF]. First, we expect our research to be useful in the initial recruitment process, because knowledge of the relation between occupations and volunteering motivation can help create targeted ads to attract volunteers. Second, this research can be useful when allocating tasks to volunteers, taking into account not only the needs of NPOs but also the volunteers' motivations and occupations. Third, our results have implications for the management and design of corporate volunteering programs, by providing insights about what motivates volunteers in different occupational and sectorial settings. We provide detailed managerial implications in the conclusion of this paper.

3

This is an author version of a paper accepted in December 2023 by the

International Review on Public and Nonprofit Marketing

Another contribution of our research relates to the data that we used. Ready-made surveys analysing motivations to volunteer are commonly employed in volunteering research. Authors have raised concerns about the use of predefined questions, as they can induce volunteers to think about motives they had not considered (Allison et al., 2002;[START_REF] Chacón | Psychosocial factors that influence volunteer work: A pilot study[END_REF][START_REF] Chacón | Motives for volunteering: Categorization of volunteers' motivations using open-ended questions[END_REF][START_REF] Wilson | Volunteerism research: A review essay[END_REF]. On the other hand, interviews can reveal a wider variety of motivations but are costly to analyse in large numbers (Hallett et al., 2020;Goudeau & Baker, 2020). They are also often restricted to specific contexts and involve a limited number of volunteers, which makes it difficult to provide general insights. In recent years, digital platforms have emerged to match volunteers with NPOs, enabling potential volunteers to express their motivations to volunteer [START_REF] Maki | Investigating similarities and differences between volunteer behaviors: Development of a volunteer interest typology[END_REF]. Data generated by these platforms has enabled researchers to carry out large scale analyses, while avoiding the disadvantages of ready-made questionnaires. They also facilitated detailed studies covering a wide range of actors, as they spanned across multiple sectors of activity. In this paper, we analyse the motivations of volunteers in France based on open texts written in the French platform "Tous Bénévoles" (All Volunteers). These texts consist in short statements written by potential volunteers explaining their motivations to volunteer. Analysing these texts has enabled us to shed light on variations in motivations across heterogeneous volunteers.

To address our research question, we first categorised the motivations for volunteering by using the Volunteer Functions Inventory (VFI) [START_REF] Clary | The motivations to volunteer theoretical and practical considerations[END_REF]. A detailed reading of the texts revealed additional factors driving volunteering, which were not included in VFI. In the second phase, a regression analysis enabled us to explore whether the difference between these drivers among people could be explained by their occupations. We found that providing resources and skills was a common and significant motivation for people of all occupations, compared to the motivations of people without any fixed occupation. However, with respect to altruism and social motivations, occupations mattered in different ways that will be detailed in the next section.

The paper is organized as follows: we provide the theoretical background in section 2, the data and methodology used to investigate our research question in section 3, our results and their discussion in section 4, before concluding in section 5.

Theoretical background

Volunteering motivations

In the research on volunteering motivations, "the fundamental inquiry is related with understanding the processes that move people into action" [START_REF] Clary | Understanding and assessing the motivations of volunteers: A functional approach[END_REF](Clary et al., , p. 1517)). The authors proposed the Volunteer Functions Inventory (VFI), a functional approach to volunteering based on the premise that "different people engage in the same volunteer activity but do so to fulfil different motives" (Clary & Snyder, 1999, p. 156).

In its original formulation, the VFI comprised six types of functions served by volunteering. The "Career" motive corresponded to cases where volunteering was desired to advance one's professional career. "Enhancement" referred to volunteers willing to enhance their ego, notably to feel better about themselves. "Protective" corresponded to volunteers seeking to protect their own self from potential negative influences. As for the "Social" motive, it related to social adaptation, since volunteers can be influenced from their external environment and social circles. "Understanding" was put forward when volunteers wanted to increase their knowledge and experiences of the external world. Finally, the "Values" motive referred to the altruistic behaviour of volunteers expressing concerns for a specific societal cause (social and/or ecological).

Many studies have used VFI to explore the motivations of volunteers in different settings, populations, and types of inquiries (Chacón et al., 2007). For example, some have focused on older volunteers and retired population [START_REF] Principi | The role of work status on European older volunteers' motivation[END_REF]Yoshioka et al., 2007), on age and gender [START_REF] Burns | The effect of gender on the motivation of members of generation Y college students to volunteer[END_REF][START_REF] Okun | Age and motives for volunteering: Testing hypotheses derived from socioemotional selectivity theory[END_REF][START_REF] Vázquez | Expressive and instrumental motivations explaining youth participation in non-profit voluntary associations: An application in Spain[END_REF], on personality [START_REF] Liao-Troth | Are they here for the long haul? The effects of functional motives and personality factors on the psychological contracts of volunteers[END_REF], on students and young people [START_REF] Gage | Volunteer motivations and constraints among college students[END_REF][START_REF] Marta | Volunteerism during young Adulthood: An Italian investigation into motivational patterns[END_REF], on task preferences [START_REF] Maki | Investigating similarities and differences between volunteer behaviors: Development of a volunteer interest typology[END_REF] or overseas [START_REF] Meneghini | A meaningful break in a flat life: The motivations behind overseas volunteering[END_REF].

Criticisms to VFI

Despite that rich VFI literature, some scholars have raised concerns [START_REF] Shye | The motivation to volunteer: A systemic quality of life theory[END_REF], notably about the extent to which suggested functions were exhaustive and exclusive [START_REF] Wilson | Volunteerism research: A review essay[END_REF], proposing VFI extensions or adaptations [START_REF] Selinske | Understanding the motivations, satisfaction, and retention of landowners in private land conservation programs[END_REF]Jones, 2004). The importance of enabling open texts by volunteers, instead of closed questionnaires has also been stressed (Chacón et al., 2012;Allison et al., 2002;[START_REF] Chacón | Psychosocial factors that influence volunteer work: A pilot study[END_REF]. In VFI-based studies, respondents are often presented with a set of predefined questions, which may induce volunteers into thinking about unthought-of motives (Wilson, 2012, p. 181).

Besides, such closed questionnaires can push respondents into confusing cause and effect, namely their ex-ante motivation to engage in volunteering versus what they expect after having decided to volunteer [START_REF] López-Cabanas | Apoyo social, redes sociales e grupos de autoayuda[END_REF]. On the other hand, open questions to understand volunteering motives are costly to analyse properly, and researchers' subjectivity can pose problems when doing so [START_REF] Chacón | Motives for volunteering: Categorization of volunteers' motivations using open-ended questions[END_REF]. But by using open questions, researchers could identify a wide range of factors that drive volunteering (Hallett et al.,2020;Goudeau and Baker, 2020;Allison et al., 2002).

The context is also important when studying volunteering motivations and should be accounted for. While individual-oriented approaches provide insights into the reasons behind volunteering by focusing on individual traits and motivations, contextual factors shaping these motivations need to be explored to obtain a robust analytical framework [START_REF] Shye | The motivation to volunteer: A systemic quality of life theory[END_REF][START_REF] Wilson | Volunteerism research: A review essay[END_REF]. Theories related to the social context as an antecedent for volunteering [START_REF] Weenink | Taking subjectivity and reflexivity seriously: Implications of social constructionism for researching volunteer motivation[END_REF] often take into account variables like cultural differences (Boz & Pala, 2007;[START_REF] Demir | Deepening knowledge on volunteers using a marketing perspective: Segmenting Turkish volunteers according to their motivations[END_REF][START_REF] Enjolras | Explaining the varieties of volunteering in Europe: A capability approach[END_REF][START_REF] Gil-Lacruz | Individual and social factors in volunteering participation rates in Europe[END_REF], external events [START_REF] Omoto | Considerations of community: The context and process of volunteerism[END_REF][START_REF] Chambré | The volunteer response to the AIDS epidemic: Implications for research on voluntarism[END_REF], regional factors (Anheier & Salomon, 1999), social networks and contacts [START_REF] Bekkers | Participation in voluntary associations: Relations with resources, personality, and political values[END_REF], or social status [START_REF] Einolf | Who volunteers? Constructing a hybrid theory[END_REF]. Last but not least, a contextual factor that might influence individual motivations is the occupation of volunteers (Wilson & Musick, 1997a).

Occupations and volunteering motivations

Occupations can have habitual and long-term effects on people. They define "important social entities characterized by a shared cultural milieu" (Lampert & Rutherford, 2020, p. 627). Sharing similar work roles and cultures can result in adopting similar norms and behaviours, both in organizational [START_REF] Kwantes | Do occupational groups vary in expressed organizational culture preferences? A study of six occupations in the United States[END_REF][START_REF] Wenger | Communities of practice: The organizational frontier[END_REF] and individual activities [START_REF] Lambert | Occupational inequalities in volunteering participation: Using detailed data on jobs to explore the influence of habits and circumstances[END_REF][START_REF] Webb | Do occupational group members vary in volunteering activity?[END_REF]Wilson & Musick, 1997a;[START_REF] Wilson | Volunteering[END_REF][START_REF] Crawford | Understanding the mobilization of professionals[END_REF]. It makes sense to ask if similar volunteering motives can also be explained by sharing similar work subcultures.

For instance, [START_REF] Wilensky | Orderly careers and social participation: The impact of work history on social integration in the Middle Mass[END_REF] has been a pioneer in postulating community involvement and volunteering work as an extension of people's jobs, and in studying how job characteristics could predict volunteering behaviour. In a leading study, Wilson and Musick (1997b) explored whether different occupational subcultures were influencing volunteering behaviour. They found that volunteering was more common among jobs with high status and skill requirements. Indeed, past literature repeatedly confirmed that occupying higher status jobs was associated with higher rates of civic engagement [START_REF] Smith | Determinants of voluntary association participation and volunteering: A literature review[END_REF]Wilson & Musick 1997b). These results were confirmed for professionals as compared to manual workers [START_REF] Rotolo | Employment sector and volunteering: The contribution of nonprofit and public sector workers to the volunteer labor force[END_REF], for people with higher education levels, and for those in more favourable socioeconomic conditions [START_REF] Lambert | Occupational inequalities in volunteering participation: Using detailed data on jobs to explore the influence of habits and circumstances[END_REF]. Why are these patterns observed?

Studies provided different explanations based on the spillover theory, which focuses on the possible interactions between multiple domains in one's life [START_REF] Marks | Multiple roles and role strain: Some notes on human energy, time and commitment[END_REF]. This theory postulates that different domains in one's life could have enhancing or compensating effects on each other [START_REF] Grube | Role identity, organizational experiences, and volunteer performance[END_REF][START_REF] Piliavin | Role as resource for action in public service[END_REF]. It is central to the role identity theory of volunteering, because these effects could help predict long term volunteering [START_REF] Grube | Role identity, organizational experiences, and volunteer performance[END_REF][START_REF] Van Ingen | I volunteer, therefore I am? Factors affecting volunteer role identity[END_REF].

First, spillover effects between job and volunteering can originate from job requirements. For example, This is an author version of a paper accepted in December 2023 by the International Review on Public and Nonprofit Marketing certain jobs demand more social interactions and thus might influence out-of-job behaviour [START_REF] Wilson | Volunteering[END_REF]. Many professionals are involved in associations' community building to increase their own social capital, since their jobs involve building local networks. In the case of lawyers for example, volunteering is a "socially approved method of getting to be known by other members of the community" (Musick & Wilson, 2008, p. 136). Moreover, certain jobs explicitly request carrying out volunteering activities.

Second, spillover effects can operate through the resources and skills used on a specific job. One might be inclined to use these skills outside the job context, especially when certain "civic skills" acquired on the job are useful for volunteering, such as management or networking skills (Wilson & Musick, 1997a).

Besides, prestigious jobs are associated with higher degrees of volunteering because they enable greater flexibility and autonomy [START_REF] Musick | Volunteers: A social profile[END_REF], enhance human capital (ibid.), and increase social connections [START_REF] Wiertz | A bridge too far? Volunteering, voluntary associations, and social cohesion[END_REF]. Therefore, some jobs are more likely to endow people with civic skills transferrable to a diverse range of civic engagement forms. Through their occupation, people can acquire such resources and skills deemed important in volunteering, which makes it less costly for them to offer these services [START_REF] Musick | Volunteers: A social profile[END_REF]. Jobs that involve administrative tasks, strategic decisionmaking, or public presentations enhance volunteering experiences [START_REF] Schlozman | Civic participation and the equality problem[END_REF]cited in Musick & Wilson, 2008). When it comes to strategic decision-making, experienced managers are confident with their decision-making routines such as dealing with forward-looking challenges, which "greatly reduce individual level cognitive demands" and enable focusing attention on other tasks (Becker & Knudsen, 2005, p. 750). As [START_REF] Musick | Volunteers: A social profile[END_REF] Another finding in the literature highlights the peculiarities of the sector and context of volunteers' jobs. Public sector employees tend to develop mental models of citizenship duties, leading them to prioritise helping others and strengthening community [START_REF] Musick | Volunteers: A social profile[END_REF][START_REF] Rotolo | Employment sector and volunteering: The contribution of nonprofit and public sector workers to the volunteer labor force[END_REF]. Their setting also favours paying greater attention to humanitarian values, having a stronger sense of social responsibility, and showing more concern to minority groups [START_REF] Brewer | Building social capital: Civic attitudes and behavior of public servants[END_REF][START_REF] Crewson | Public service motivation: Building empirical evidence of incidence and effect[END_REF]. Besides, public sector workers tend to have an easier access to volunteering opportunities [START_REF] Ertas | Public service motivation theory and voluntary organizations: Do government employees volunteer more?[END_REF]. In the private sector, it is corporate volunteering programs (CVP) that create a favourable setting to increase volunteering [START_REF] Mayer | Exploring the whole value of corporate volunteering[END_REF][START_REF] Hatami | Happiness management through corporate volunteering in advancing CSR[END_REF]. CVP refers to activities through which employees donate their time, knowledge or skills, while employers provide some kind of support (e.g. permitted leave to carry out societal missions). CVP can have various purposes like contributing to a social cause, meeting the needs of a community and/or of employees by promoting their personal development, or generating benefits for the company (Licandro, 2023, p. 100). These programs have significant benefits in terms of social value, economic value, and private value (i.e. for individuals and organisations) [START_REF] Mayer | Exploring the whole value of corporate volunteering[END_REF]. They were found to have significant effects on skill development and employee well-being [START_REF] Mayer | Exploring the whole value of corporate volunteering[END_REF]Alhinho et al., 2023).

Based on this theoretical background, our research question is the following: Are occupations of volunteers associated with their motivations to volunteer? If yes, which motivations are significant, and which are not, for different occupations? In the next sections, we carry out a detailed analysis to investigate whether and how people differ in their specific motivations to volunteer, as a function of their occupation.

Data and Methodology

Context and data

In France, volunteering plays an essential role in the third sector, a specific sector We obtained the data for this study from a leading French volunteer platform developed by the NPO Tous Bénévoles.1 After several meetings to frame the research questions, we signed a MoU that gave us access to an anonymised copy of their database for the years 2014-2018. The platform aims to match NPOs needing volunteers with potential volunteers, according to the needs and preferences of both parties. The initial application form, filled online, collects information about the candidate volunteer. All questions are not mandatory thus some can be skipped. Table 1 summarises the questions used in this study and the format of the answers obtained. Table 2 provides some descriptive statistics of the data.

< Table 1 here > <Table 2 here>

The original sample includes 26,519 applications to volunteer. However, we had to exclude an important share of the responses for one or more of the following reasons: responses from applicants residing in French overseas territories or in French-speaking North African countries (11,547), responses in which one or more of the control variables were missing (age, address, education, situation) and in which either the occupation or the motivation part was missing. This has left us with a smaller but important sample of 7,725 responses.

Empirical strategy

The study was carried out in two phases. In the first phase, we coded volunteers' open texts and classified their motivations for volunteering. In the second phase, we used these motivations as dependent variables in regression analyses to understand whether occupations could explain differences between peoples' motivations to volunteer.

Phase 1: Coding motives to volunteer

The three authors of this paper coded the texts that volunteers typed online when registering on the platform to explain their motivation. As [START_REF] Miles | Qualitative data analysis: An expanded sourcebook[END_REF] put it: "Codes are tags or labels for assigning units of meaning to the descriptive or inferential information compiled during a study. (…) They can take the form of a straightforward category label or a more complex one (…)." (p. 56). In our case, we started coding the texts submitted by each candidate volunteer with one of the motives identified in the VFI model. We used research by [START_REF] Chacón | Motives for volunteering: Categorization of volunteers' motivations using open-ended questions[END_REF] providing a range of exemplary sentences often used by volunteers to explain their motives according to the VFI instrument (cf. Table 3).

To ensure consistency among coders, a coding guide was prepared and tested. It contained specific instructions (such as the ones mentioned in the previous paragraph) and detailed explanations taken from the literature about each motive, complemented with examples of coded text. A first coding was carried out by each coder, and each coding was reviewed for consistency by a different coder. This led to some clarifications about how to label certain ambiguous texts and codes, for which all coders agreed upon.

Given the limits of the VFI instrument, we decided to keep an open eye on new volunteering motives to better fit the analysed texts. Additional motives were suggested and discussed, and when consensus was reached to retain them, all the texts were coded again in the light of the new motives. Two new motives were added to the six VFI ones: "Provision of resources and skills", and "Meeting new people in need" (cf. Section 4.1). In the end, all codes were double-checked, and in cases of conflicting codes researchers discussed each case until agreeing upon a common interpretation, which was written in the coding guide. Texts explaining motivation to volunteer varied between one sentence to one paragraph. The other three questions enabling open text answers were also collected and coded (cf. This is an author version of a paper accepted in December 2023 by the International Review on Public and Nonprofit Marketing

Phase 2: Regression analysis

Model

The motives revealed in the first phase of the study (cf. Table 3) were used as dependent variables in the second phase of the research. We used logistic regression models to determine the associations between a range of explanatory variables and a dependent variable. Logistic regressions are used when the dependent variable is a binary discrete variable [START_REF] Hosmer | Applied logistic regression[END_REF]. We built a total of eight regression models where the dependent variable was one of the volunteering motives identified in phase 1 (cf. Table 4).

Dependent variable

The dependent variable is a binary variable taking two possible values: 1 if the volunteer candidate is deemed having the corresponding motivation type, and 0 otherwise. As explained in Section 4, eight motives for volunteering were identified in the texts: Provision of skills, Values, Meeting people in need, Understanding, Enhancement of ego, Career, Social, and Protective.

Independent variable

The independent variable is the occupation of volunteers, as selected by applicant volunteers from a dropdown menu suggested by the platform. 15 occupation categories are distinguished here: No fixed occupation, Artists, Clerical (accountants, secretaries…), Engineers, Finance, Healthcare, Lawyers, Management, Military, Researchers, Salespersons, Service providers, Social workers, Students, and Teachers. This is a categorical variable whose value ranges from 1 to 15.

Control variables

We used five control variables, which proved to be explanatory in past research on VFI functions. Gender: Binary variable, taken as a control because past research has revealed that there might be differences between men and women in terms of their volunteering motivations [START_REF] Burns | The effect of gender on the motivation of members of generation Y college students to volunteer[END_REF][START_REF] Wymer | The implications of sex differences on volunteer preferences[END_REF]. Age: Categorical variable based on the year of birth. Four age categories are defined: Below 20, Between 20 and 40, Between 40 and 60, Above 60. Past literature has confirmed the impact of age on volunteering motives [START_REF] Burns | The effect of gender on the motivation of members of generation Y college students to volunteer[END_REF][START_REF] Dávila | Age and motives for volunteering: Further evidence[END_REF][START_REF] Okun | Age and motives for volunteering: Testing hypotheses derived from socioemotional selectivity theory[END_REF]. Situation: Categorical variable showing the socio-demographic situation of the volunteer candidate. We considered three categories: Active, Inactive, and Unemployed. Various studies have shown that these could significantly influence volunteering [START_REF] Gage | Volunteer motivations and constraints among college students[END_REF][START_REF] Gil-Lacruz | Individual and social factors in volunteering participation rates in Europe[END_REF][START_REF] Okun | Motivation to volunteer by older adults: A test of competing measurement models[END_REF], notably because they impacted free available time. Considering this point, we coded students as 'active'. Education: Categorical variable showing the last diploma obtained. The platform distinguishes categories presented in a drop-down menu: No diploma, Secondary school diploma maximum (brevet des collèges), High school diploma maximum (baccalaureate), Bachelor diploma maximum (L3), Graduate level minimum (M1). Rurality: Categorical variable showing the degree of urbanisation of a volunteer's location (Anheier & Salomon, 1999). This data was collected by the authors from INSEE (National Institute of Statistics and Economic Studies) based on volunteers' postal codes. Geographical areas range from the most isolated and sparsely populated to the most urbanized ones. We distinguished four categories: Strongly rural, Rural, Urban, Strongly urban.

Results and discussion

First, we discuss the six VFI motivations and the two extra ones identified in phase 1. Then, in Section 4.2 we present the results of our regression models carried out in phase 2.

Motivations for volunteering

The coding in phase 1 revealed eight categories of motivations used in a specific regression model (cf.

This is an author version of a paper accepted in December 2023 by the International Review on Public and Nonprofit Marketing

Table 3): (1) Provision of resources and skills (not in VFI), (2) Values (concern for a specific cause),

(3) Meeting new people in need (not in VFI), (4) Understanding, (5) Enhancement of ego, (6) Career, (7) Social, and (8) Protective. We explain each of these along with exemplary sentences in Table 3. Two of these motives are additional ones to the six VFI motives:

(1) Provision of resources and skills: The volunteer candidate mentions a willingness to provide a specific skill.

(2) Meeting new people in need: The volunteer candidate mentions a willingness to meet and interact with people who are the beneficiaries of the wished voluntary activity.

Six of the motives that we identified were already taken into account by the VFI instrument. For these, we used VFI-based coding because the sentences used by volunteers in our sample were equivalent to exemplary VFI sentences [START_REF] Clary | Understanding and assessing the motivations of volunteers: A functional approach[END_REF] and open text VFI sentences identified by [START_REF] Chacón | Motives for volunteering: Categorization of volunteers' motivations using open-ended questions[END_REF].

< Table 3 here > However, two motives appearing often in our sample had not been categorised as a VFI function in the literature.

The first one concerns the willingness to provide a specific resource or skill that the volunteer is endowed with (23.5% occurrence, cf. Table 3). Such skills and resources usually relate to their job, occupation, or field of specialisation. In these cases, volunteers usually did not mention why they wished to provide those skills and resources. However, when asked why they wanted to volunteer, the fact that they responded by stating a willingness to provide a specific skill matches the arguments of [START_REF] Musick | Volunteers: A social profile[END_REF]. Indeed, the authors stated that the relation between job and volunteering may not refer to self-interest, enhancement, or socio-psychological factors but to individual resources. In some cases, people volunteer because they are endowed with plenty of volunteering attributes, which makes it less costly for them to do so. They can also wish to put them to use outside their job, as explained by aforementioned spillover theories. In these cases, people's primary motive relies on being aware that their specific resources and skills are more congruous for volunteering. This result fits with rational choice theories of volunteering upholding that volunteering is a consequence of the "rational weighing of costs and benefits" (Wilson, 2000, p. 219), for example people volunteer because they have spare time and useful skills to offer. This finding is consistent with research arguing that people with higher levels of education tend to volunteer more than less educated citizens (Chambré, 1987).

The second new motive concerns the willingness to get in touch with people in need ("Meeting new people in need"). This motive was mentioned in 4.6% of the texts (cf. Table 3). A willingness to meet people in need can be interpreted in different ways with VFI, as for Understanding or Enhancement. To avoid any bias in interpretation, we coded it as a separate motive. This new motive might appear similar to the "Enhancement of ego" motive, whose exemplary sentence is "I want to make new friends" (cf.

Table 3). But the "Meeting" motive differs, since people expressed that they wanted to experience alterity with people living in conditions different to their own (aged population, people with disabilities, homeless, migrants…). Let us now present the results of our regression analyses.

Regression results

Table 4 shows the logistic regression results.

< Table 4 here >

The regression results reveal broad trends applicable to all occupations in our sample. Firstly, the odds ratio of the variable resources and skills is positive and significant for all occupations. This means that people from all occupations in the sample were significantly more likely than people without fixed occupations to express "Provision of skills and resources" as the primary motive to volunteer. Secondly, the odds ratio of the enhancement motive is negative and significant for all occupations. Our results also

This is an author version of a paper accepted in December 2023 by the International Review on Public and Nonprofit Marketing

suggest that the values and social motives depend on the occupation. We did not detect any significant relationship between occupations and the motives of "Understanding" and "Meeting people in need". Finally, there are two motivations for which only the odds ratio for students are significant. This suggests that students are significantly more likely to be motivated by "Career" compared to people with other occupations, and less likely to value the "Protective" motive compared to people without fixed occupations.

Resources and skills

Our results reveal that people from all occupations in the sample were significantly more likely than people without fixed occupations to mention the "Provision of resources and skills" as primary motive to volunteer. In other words, volunteering can be explained by the fact that for some people, notably those endowed with specific skills and knowledge, the volunteering decision can be a rational weighing of the costs and benefits of volunteering. From an economic viewpoint, because some people are endowed with skills deemed valuable for volunteering, they can reap more benefits and incur lower costs [START_REF] Wilson | Volunteering[END_REF].

Another explanation to volunteering is that occupations can have spillover effects in other domains of life, and that people may want to do more of what they already do in their jobs, but outside the job sphere.

According to spillover theories, especially when certain skills acquired on the job are useful for volunteering, one might be inclined to use these skills outside the job context (Wilson & Musick, 1997a).

If the very characteristics of people's jobs can be a "powerful sorting mechanism" when it comes to deciding whether to volunteer or not (Musick & Wilson, 2008, p. 138), authors recommend distinguishing, as much as possible, the external variables (level of education) from the internal variables (intrinsic characteristics of a job) when trying to explain volunteering through a spillover lens.

We find that health sector workers and teachers have particularly high odds ratios when it comes to the provision of resources and skills. This might be related to the fact that in the case of health workers for example, development and learning is a major motivation [START_REF] Ferreira | Motivation among hospital volunteers: An empirical analysis in Portugal[END_REF]. This may also be due to an overall high demand for their services. In past research, schoolteachers were found to volunteer more compared to people with other occupations [START_REF] Rotolo | Employment sector and volunteering: The contribution of nonprofit and public sector workers to the volunteer labor force[END_REF][START_REF] Lambert | Occupational inequalities in volunteering participation: Using detailed data on jobs to explore the influence of habits and circumstances[END_REF].

Given the skill requirements of these occupations, this result supports the argument of Wilson and Musick (1997, p. 257) according to which volunteering is more common among integrative jobs with a strong educative and welfare function. Besides, public sector employees (education & health have a strong public tradition in France) tend to be more connected with the civic sphere and more prone to engage in volunteering compared to their private sector counterparts (Lup and Booth, 2019, p. 605).

Enhancement of ego

Our results reveal that most professions have odds ratios that are significantly negative for the "Enhancement" motive. This result can be explained by the control group, composed of people with no fixed jobs. Indeed, this motive is significantly higher for people with no stable jobs, as compared to others having a specific occupation. For people with occupations, combining this result with the high odds ratio of the "Provision of resources and skills" motive, it seems that volunteering is not so much based on the motive of enhancing their ego or their skills (and resources), but rather the fact that existing skills are particularly suitable for volunteering. It is important to underline that not having a stable occupation does not equate to unemployment. In this paper, we take a stable occupation as "work in which one engages regularly especially as a result of training" (definition taken from the Merriam-Webster online dictionary), and find that its absence can urge people to volunteer to enhance their skills, whether they are employed or not. This result implies that people without a fixed occupation might expect to enhance their skills and compensate for their professional instability, or lack of an occupation related identity through

Occupations according to altruism and social scale

The odds ratios of the "Values" motive are significantly negative for lawyers, health workers, teachers, clerical staff and financial sector workers. This result, especially considering the first three of these occupations, is reminiscent of the long-standing literature questioning whether people in certain occupations are more altruistic than others [START_REF] Brekke | Selfish bakers, caring nurses? A model of work motivation[END_REF][START_REF] Jacobsen | Are nurses more altruistic than real estate brokers[END_REF]. These occupations are traditionally associated with the orientation of caring for others, and thus people in these occupations are "expected" to exhibit more altruistic behaviour compared to others. Our results are at odds with this "myth" [START_REF] Jacobsen | Are nurses more altruistic than real estate brokers[END_REF]. One explanation could be that people in these occupations may have a stronger need to preserve a stable and positive self-image [START_REF] Brekke | Selfish bakers, caring nurses? A model of work motivation[END_REF]), an explanation based on the Homo economicus representation of humans [START_REF] Haski-Leventhal | Altruism and volunteerism: The perceptions of altruism in four disciplines and their impact on the study of volunteerism[END_REF] according to which the rewards obtained from being altruistic enter the utility function. From a more pragmatic point of view, during the recent years a decline in altruism in some professions has taken place, including in healthcare ones, notably due to increased workloads [START_REF] Burks | The legacy of altruism in health care: The promotion of empathy, prosociality and humanism[END_REF]. The negative relation between these occupations and the "Values" motive suggests that people could simply be motivated because they have more resources fitting volunteering needs, rather than because of pure altruistic concerns.

Three occupations have significant positive odds ratios of the values motive in volunteering: artists, service sector workers, and social workers. Previous literature detected a possible association between prosocial traits and artistic creation [START_REF] Kou | The relationship among different types of arts engagement, empathy, and prosocial behavior[END_REF]. Intrinsic values nurtured on the job can guide subsequent behavior [START_REF] Deci | The 'what' and the 'why' of goal pursuits: Human needs and the selfdetermination of behavior[END_REF][START_REF] Grant | Does intrinsic motivation fuel the prosocial fire? Motivational synergy in predicting persistence, performance, and productivity[END_REF][START_REF] Spreitzer | Psychological empowerment in the workplace: Dimensions, measurement, and validation[END_REF], and artistic professions usually have high intrinsic motivations (Amabile et al., 1994). As far as social work is concerned, the results highlight the differences between public and private sectors settings when it comes to volunteering. Integrative jobs do tend to strengthen "collectivist preferences" (Wilson & Musick, 1997a, p. 257) and enhance altruistic behavior more than other adaptive jobs (Lewis & Epstein, 1979). More precisely, we find that for social work, whose settings bind together people with different social class, race, or region, altruistic motives are a significant driver of volunteering, at least in the case of France. The specificity of social work in terms of providing such a social context is also evident when it comes to the positive odds ratio for the social motive among social workers. The social motivation explains volunteering by the influence of one's social environment.

Other occupations for which the social motivation has significant positive odds ratio are artistic ones, research, finance, and being a student. The positive odds ratio for artistic occupations could be due to the high number of non-profit organizations in the field of arts and culture in France. People in artistic occupations maybe more likely than others to be surrounded by others who volunteer for these organizations, and this can explain the social influence between them. As for students the key role of social influence from primary reference group members (like parents, siblings, close friends) in volunteering has been evidenced before [START_REF] Francis | The functions and norms that drive university student volunteering[END_REF]. Students are also different in terms of the social motive, where reference groups (like the influence of parents, siblings, close friends) seem to play an important role in their volunteering, in line with previous research [START_REF] Francis | The functions and norms that drive university student volunteering[END_REF].

Protection, career, meeting people, understanding motivations

When it comes to the meeting people in need and understanding motivations, we don't find any significant association with occupations, but some control variables are significant which we explore below. Finally, when it comes to the career and social motivations of volunteering, only students seem to be different from other occupations. This result is in line with the previous research showing that resumé building, and career prospects is an important motivation for students to volunteer, especially in countries This is an author version of a paper accepted in December 2023 by the International Review on Public and Nonprofit Marketing with a positive signalling value of volunteering [START_REF] Handy | A cross-cultural examination of student volunteering: Is it all about résumé building?[END_REF] like in France.

The effects of control variables

When it comes to the role of gender, we find that women have higher odds for Values, Career and Social motives, but lower odds for the resource Provision motive. This is in line with previous research showing that women possessed a large advantage in prosocial motivation that correspond to the Values motive (Einolf, 2010, p. 16;cited in Wilson, 2012). Also, according to the gender identification approach, women tend to have higher societal expectations and be more "caring, giving and communal" because of social construction (Marshall & Taniguchi, 2012, p. 218).

Concerning the role of education, our results reveal that the lower the education level, the weaker the "Provision of resources and skills" and "Career" motives, and the higher the odds of volunteering because of altruistic motives. These results support previous research [START_REF] Lambert | Occupational inequalities in volunteering participation: Using detailed data on jobs to explore the influence of habits and circumstances[END_REF]. We also find that the lower the diploma the higher the values motive odds. However, as education level plays a role in volunteering, a part of the job's impact may be due to the education level required by the job. For example, [START_REF] Okun | Motivation to volunteer by older adults: A test of competing measurement models[END_REF] found that as educational level increases, the Enhancement motive tends to weaken among volunteers.

In terms of the effects of age, previous research has underlined a strong impact on volunteering motivation [START_REF] Kottasz | How should charitable organizations motivate young professionals to give philanthropically[END_REF][START_REF] Lwin | An investigation of the characteristics of Australian charitable donors[END_REF], and the fact that younger people volunteer more than others to improve their career and skills [START_REF] Hopkins | Young people's motivations for undertaking voluntary work[END_REF][START_REF] Snyder | Volunteerism: Social issues perspectives and social policy implications[END_REF]. Our results specify these elements and reveal a strong positive association between age and the resource Provision motive. Indeed, compared to younger people, people above 20 are more likely to initiate volunteering to provide resources and competences. This is in line with the literature underlining that "many professionals use community-based groups to build social capital for their practice" (Wilson & Musick, 1997a, p. 253).

Since social capital accumulates with experience, older people tend to have more resources to share through volunteering. It is also consistent with the self-interestedness of young volunteers.

When it comes to the relation between age and the Values motive, compared to the youngest (below 20) we find that people in the middle age group (between 20 & 59) are significantly less motivated by altruistic purposes. This contradicts other findings stressing that the Values motive is equally highly important across all ages [START_REF] Snyder | Volunteerism: Social issues perspectives and social policy implications[END_REF]. However, our findings remain consistent with the literature highlighting a strong relationship between young volunteers' altruism and all VFI motives [START_REF] Burns | Motivations to volunteer: The role of altruism[END_REF].

Our results are also in line with previous research indicating a negative association between the Understanding motive and age (Dávila & Días-Morales, 2009;[START_REF] Okun | Age and motives for volunteering: Testing hypotheses derived from socioemotional selectivity theory[END_REF]. People above 20 are less motivated due to the Understanding motive, compared to younger people. Our results also support previous findings stating that the senior population is not motivated by career and understanding (Dávila & Días-Morales, 2009;[START_REF] Okun | Motivation to volunteer by older adults: A test of competing measurement models[END_REF][START_REF] Okun | Age and motives for volunteering: Testing hypotheses derived from socioemotional selectivity theory[END_REF], as revealed by the negative odds ratio of retired people. The same effect is valid for the motive of meeting people in need, given by the 3 rd regression model. People below the age of 20 are significantly more likely to initiate volunteering so as to be in contact with the people in need.

Our results reveal that compared to people who are inactive in employment, unemployment is associated with Career and Understanding motives, and less associated with the Values motive [START_REF] Snyder | Volunteerism: Social issues perspectives and social policy implications[END_REF]. As for the Protective motive, results reveal that active people are significantly less likely to volunteer to protect themselves from negative effects.

According to previous research, the environment can influence volunteering motivations [START_REF] Wilson | Volunteering[END_REF]. For example, Stukas et al. (2015, p. 43) underline that communities provide access to networks facilitating volunteering experiences, which reinforces people's ability to "forge secure relationships with others". [START_REF] Wuthnow | Mobilizing civic engagement: The changing impact of religious involvement[END_REF] found that people living in small towns emphasize solidarity and community

This is an author version of a paper accepted in December 2023 by the International Review on Public and Nonprofit Marketing benefits, whereas suburbanists emphasize self-development. For France, our results do not support previous research along these lines. Our results suggest that there are significant differences between strongly rural and strongly urban areas when it comes to altruistic volunteering drivers. Volunteer candidates in highly urban areas have a higher odds ratio for the altruistic (Values) motive, compared to strongly rural areas. In addition, their motives seem to be less focused on Understanding and Enhancement, compared to volunteers living in rural areas. Thus, as opposed to the literature our results show that people from more urban areas emphasize solidarity and altruism as a volunteering motive compared to the ones living in rural areas composed of small towns.

Conclusion

By drawing upon the open-ended texts written by a large sample of online candidate volunteers living in France, we explored the extent to which the different motivations to volunteer were correlated with their occupations. Two general results apply to all occupations in the sample. First, people with any occupation are significantly more likely than people without occupation to provide a specific skill or resource related to their occupation. In other words, the provision of resources and skills is a major driver of volunteering, especially for people well-endowed with those skills deemed valuable in volunteering.2 Second, people from all occupations are significantly less likely than people without occupation to be motivated by the Enhancement of the ego. Another result from our study is that lawyers, healthcare workers, teachers, clerical workers and financial sector workers have lower altruistic motives than people without fixed occupations. On the other hand, artists, social workers and service sector workers having strong altruistic motives. Finally, we also find that social influence is a volunteering driver for students, finance and clerical jobs, artists, and researchers, and career motive is especially important for students.

Managers of volunteering programs, whether in NPOs or in corporations, should always consider the volunteers' willingness to provide resources and skills, and hence employ these in offered mission. Satisfying volunteers' initial motivations increases the quality of volunteering work and volunteer attachment to the organization [START_REF] Brudney | Designing and managing volunteer programs[END_REF]Finkelstein, 2015). Our results can be helpful in three ways: first in seeking and recruiting volunteers, second in task allocations and designing volunteering settings, and third in the management of relations between corporations and NPOs.

When it comes to the recruitment of volunteers, managers need to take into account the heterogeneity of volunteering motivations. Depending on what kinds of skills are searched for, and which tasks need to be performed by volunteers, if managers know what motivates people with specific occupations, search will be easier either through targeted ads or by mobilising ad hoc environments. For example, if the task involves financial aspects for which the social motive is significant, targeted ads could reflect how volunteering is becoming the "norm" among finance sector employees, rather than stressing altruistic values. For recruitment, depending on their needs NPOs can attract specific occupations based on associated motivations. For example, when seeking volunteers, if an NPO values altruistic motives, our results suggest targeting artists, social workers, and service providers. On the other hand, if altruistic volunteers are not a priority, and depending on the skills needed, NPOs should target healthcare and finance workers, teachers and clerics.

Our research also provides insights about how to design volunteering programs, especially regarding task allocation and the design of attractive settings for volunteers. Placing volunteers in positions that meet their skills is one of the most important factors in volunteer management [START_REF] Brudney | Designing and managing volunteer programs[END_REF]. For volunteers who value serving a cause more than other volunteers (like artists, social sector and service sector employees), NPOs should offer them missions meeting that motive, for example in the form of poverty reduction campaigns or biodiversity protection ones. One of the most important steps in designing volunteering programs is establishing a rationale for volunteer involvement [START_REF] Brudney | Designing and managing volunteer programs[END_REF]. Attracting professional skills possessed by volunteers but not readily available in NPOs is a common objective for This is an author version of a paper accepted in December 2023 by the International Review on Public and Nonprofit Marketing the latter. By knowing the motivations associated to specific occupations, NPOs can better allocate tasks between their paid employees and volunteers. Managers should always consider that volunteers with specific occupations have a willingness to provide resources and skills, and hence employ these in the missions they will accept to carry out. Finally, when trying to retain volunteers, NPO managers could use the fact that for some volunteers such as students, finance workers, clerics, artists and researchers, a key motive is the influence of their external environment and social circles. Reducing turnover among these volunteers might also be achieved by popularizing volunteers' activities to the general public and their social circles, for example through social media or live events.

Finally, our research has implications for the development, design and improvement of collaborative projects between nonprofits and other (public and private) organisations, to align the motivations of employees with the needs of nonprofits. Research shows that CVPs create a range of benefits including social, economic, and private values, and contribute to the skill development and well-being of employees [START_REF] Mayer | Exploring the whole value of corporate volunteering[END_REF]Alhinho et al., 2023). Employee satisfaction in CVP strongly depends on their experiences and the extent to which their motivations are met [START_REF] Brudney | Designing and managing volunteer programs[END_REF]. If corporate managers have a good understanding of the individual skills of employees, they can make volunteering more attractive by appealing to their specific motivations in an occupation, while collaborating with NPO managers to allocate tasks. Task allocation should be in line with the skills and capabilities of employees, since the provision of skills and resources seems to be a very strong motivation for all occupations in our sample. On the contrary, while skills development is an important outcome of CVP [START_REF] Mayer | Exploring the whole value of corporate volunteering[END_REF]Alhinho et al., 2023), it should be kept in mind that what motivates volunteers in many occupations does not seem to be enhancement, according to our results. Therefore, emphasizing how volunteering would enhance volunteers' skills maybe an ineffective way to increase the attractiveness of CVP.

In this research, we used open text rather than questionnaires that are often used in volunteering research.

Using open texts conveys the benefit of preventing volunteer candidates from coming up with motivations they had not considered beforehand. These texts could be analysed with AI based on a grid defined by researchers. But the results might be biased because some voluble people may write more than others, which makes data standardization difficult. However, most of our results align with the general patterns revealed in previous research on volunteering, which suggests that these biases are not considerable.

A word of caution is necessary in interpreting our results. We did not carry out a longitudinal analysis, which means that it is difficult to infer causality between occupations and motivations to volunteer. Nevertheless, our cross-sectional data and analysis highlight patterns of correlation between occupations and motivations for different people. These results raise some questions worth investigating in future research. One area of investigation could be differences in countries. Could these results be specific to the French case? Other studies found national peculiarities in terms of volunteering behaviours, as [START_REF] Webb | Do occupational group members vary in volunteering activity?[END_REF] who suggested that in North America altruism tended to be a very strong motive, whereas it was personal values in the case of Canada. Further collaborative research on the relation between occupations and volunteering in different contexts would help achieve this aim.

Allison, L., Okun, M., & Dutridge, K. (2002) Includes people expressing that they want to make other benefit from their skills: "I want to offer my competences to a nonprofit" "I want to make my competences be utilized" "I am endowed with (these competences) and I want to use these for a nonprofit" "I want to offer my services/competences for free to people in need"

23.5

Values (2)

Includes texts expressing a deep concern with a particular cause: "The situation of homeless people breaks my heart" "The world needs more solidarity" "I am deeply concerned about the environment" "I just want to help"

38.6

Meeting new people in need (3) Includes people stating a desire to meet others 4.6 Understanding (4)

Includes texts expressing a need to understand a reality that differ from their context: "I want to discover other ways of living" "I want to discover new cultures" "I want to learn about the world of nonprofit organizations" 4.5

Enhancement of ego (5)

Includes people mentioning explicitly that they volunteer to enhance their ego: "I enjoy (an activity) so I want to give free classes" "I am in search for a new challenge in my life" "I want to test my capacity to succeed in a mission" "I want to feel useful" "I want to make new friends"

31.4

Career (6)

Includes people mentioning explicitly that their job or career demands volunteering: "Volunteering will help me realize my professional project" "My boss, or my school wants me to carry out a volunteering activity" "I want to develop skills that will be helpful for my career" 4.5

Social (7)

Includes motives where people explicitly state an appreciation of others (peers, family, ...): "My parents are volunteers so I would like to try as well" "I am influenced by the experiences of my friends/family" "My parents / friends suggest that I volunteer" 1.6

Protective (8)

Includes people explicitly stating a traumatic past experience: "I had (difficulties) and I was helped by others, so I want to do the same now" "I feel useless so I want to feel active"

1.6 * Because some people expressed more than one motive, the sum exceeds 100%. A total of 830 people had more than one motive, and 18 people had more than two motives.

This is an author version of a paper accepted in December 2023 by the International Review on Public and Nonprofit Marketing

  This is an author version of a paper accepted in December 2023 by theInternational Review on Public and Nonprofit Marketing volunteering

  This is an author version of a paper accepted in December 2023 by theInternational Review on Public and Nonprofit Marketing country, 12.5 million people had volunteered, and 1,776,000 people were employed by 152,700 NPOs having salaried personnel. But despite the importance of the third sector in France and its reliance on volunteering, there are no academic studies analysing motivations to volunteer.

(Economie Sociale et Solidaire -ESS) formalized by the 2014 "ESS law" (n° 2014-856, July 31). According to data published at the end of 2021 (Recherches & Solidarités, 2021), in 2020 about 65,000 NPOs were created in the

  Table 1). They concerned skillsThis is an author version of a paper accepted in December 2023 by theInternational Review on Public and Nonprofit Marketing and competences, observations and comments, and last diploma. In some cases, when motives were contained in responses to other questions, we coded them as well.

  This is an author version of a paper accepted in December 2023 by the International Review on Public and Nonprofit Marketing volunteering work.

Table 1 . Data collected and format Question Format

 1 . Assessing volunteer motives: A comparison of an openended probe and Likert rating scales. Journal of Community & Applied Social Psychology, 12, 243-255. Alhinho, G., Proença, T., & Ferreira, M. R. (2023). Corporate Volunteering Impacts: A Tripartite Approach Through the Employees' Perceptions. International Journal of Social Ecology and Sustainable Development, 14(1), 1-20. Amabile, T. M., Hill, K. G., Hennessey, B. A., & Tighe, E. M. (1994). The Work Preference Inventory: This is an author version of a paper accepted in December 2023 by the International Review on Public and Nonprofit Marketing This is an author version of a paper accepted in December 2023 by the International Review on Public and Nonprofit Marketing

	Age, gender	Birth date for age; two options for gender (male/female)
	Location	Postal code in "Metropole" (European France), or overseas France. Only Metropole codes were kept for homogeneity concerns
	Socio-demographic situation	Categories: active, inactive, unemployed (students are considered 'active')
	Current job	Categories: artist, clerical (accounting, secretary…), engineer, finance, healthcare, journalist, lawyer, manager, military, researcher, salesperson, service provider, social worker, teacher.
	Motivation to volunteer	Open text
	Skills and competences	Open text
	Observations and comments	Open text
	Last diploma	Open text

Table 3 . Volunteering motives used in regressions Motive to volunteer Corresponding regression model (cf. Table 4)

 3

	Explanation	Occur-rence (%) *

Table 4 . Regression results

 4

	Logistic regression models (1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)
		Res	Val	Meet	Und	Enh	Car	Soc	Prot
	Gender	0.73	1.27	1.65	1.25	0.98	1.45	1.55	0.70
		-4.40	4.23	3.43	1.65	-0.37	2.59	2.34	-1.63
	Age (< 20 omitted)
	≥ 20 and < 40 ≥ 40 and < 60 ≥ 60 Situation (Inactive om.)	1.96 4.15 2.09 4.21 1.91 2.91	0.77 -3.23 0.76 -2.54 0.85 -0.90	0.54 -3.69 0.41 -3.50 0.22 -3.44	0.61 -2.99 0.52 -2.71 0.14 -2.48	1.22 2.56 1.19 1.58 1.12 0.69	0.79 -1.74 0.74 -1.24 1.27 0.46	1.00 -0.35 0.68 -1.08 1.00 -0.01	1.20 0.41 1.62 1.19 1.74 0.95
	Active Currently unemployed	0.90 -0.74 0.93 -0.43	0.99 -0.04 0.74 -2.26	0.72 -1.06 0.60 -1.57	3.97 2.43 3.79 2.32	0.97 -0.32 1.09 0.67	4.42 2.66 8.57 3.84	0.83 -0.40 0.79 -0.46	0.34 -2.83 1.37 0.90
	Jobs (No job om.)

Cf. https://www.tousbenevoles.org.

For less educated people, a large pool of potential volunteers, altruistic motives are a significant driver of volunteering, at least in the case of France.

This is an author version of a paper accepted in December 2023 by the

International Review on Public and Nonprofit Marketing

No funding was received for conducting this study.

This is an author version of a paper accepted in December 2023 by the

International Review on Public and Nonprofit Marketing