Mareike C Jahnke

Tania Pape

Dr F Ekkehardt Hahn
email: fehahn@uni-muenster.de

Dr Herbert Schumann

Synthesis and Characterization of Gold(I) and Gold(III) Complexes Derived from Benzimidazolin-2-ylidene Ligands

Keywords: N-Heterocyclic Carbene, Gold, Oxidation, Molecular Structures

Substitution of the chloro ligand in (N,N´-dialkylbenzimidazolin-2ylidene)gold(I) chlorides (alkyl = methyl, ethyl, propyl, butyl) succeeded by treatment of the gold chloride complexes with lithium bromide in acetone leading to the gold complexes of the type [AuBr(L)] 1-4. Furthermore, the Au-C carbene bond in complexes 1-4 is inert towards a change of the oxidation state of the metal center. Complexes 1-4 have been oxidized chemically with elemental bromine leading to the gold(III) carbene complexes of the type [AuBr 3 (L)] 5-8. The molecular structures of the gold(I) complexes 1, 2 and 4 exhibiting a linear topology are presented together with the two molecular structures of the square-planar gold(III) complexes 6 and 8.

Introduction

Today, N-heterocyclic carbenes (NHCs) are well established ligands in organometallic chemistry [1]. This development rests on the easy access to differently substituted NHCs making them a good alternative to phosphines in the design of new organometallic catalysts [1,2]. The facile access to NHCs is complemented by the superior σ-donor properties of the carbene ligands compared to the most basic phosphines [3] leading to a remarkable stability of the carbene complexes against air, moisture, heat and oxidizing conditions [1]. Recently, poly-NHC ligands have also been used as building blocks for metallosupramolecular structures. Linear di- [4] as well as tri-or tetra-NHC ligands [5] have been employed for the generation of molecular rectangles or cylindrical molecules which provide cavities suitable as host for guest molecules during a catalytic reaction [6].

A large portion of all known NHC complexes contain a group 9 or 10 transition metal [2a, 7] or ruthenium [8] as the metal center. In addition, many silver carbene complexes [9] have been prepared after Wang and Lin [10] reported in 1998 the very useful carbene transfer reaction utilizing silver NHC complexes. Today, this carbene transfer reaction has developed into a versatile and well established procedure for the synthesis of transition metal NHC complexes [9].

Gold NHC complexes have only recently attracted interest, although the preparation of such complexes has been reported as early as 1998 [10]. This development supports the recent resurgence of interest in gold catalyzed reactions [11] which in turn has initiated a search for new gold NHC complexes [12]. Today gold NHC complexes are used as pharmaceuticals [13], in photophysical devices [14], and as catalysts for selected transformations in homogeneous catalysis [15].

The inertness of the Au-C NHC bond during substitution reactions at linear [AuX(NHC)] complexes was noted by Wang and Lin as early as 1999 [16]. Ligand X in complexes of the type [AuX(NHC)] can be substituted for halides [16, 17], nitrogen-[18, 19] and phosphorous-donors [4a, 19] or even hydroxide [20]. It has also been shown, that the Au-C carbene bond is not affected if gold(I) NHC complexes bearing unsaturated imidazolin-2-ylidene or saturated imidazolidin-2-ylidene ligands are oxidized with bromine [21] or chlorine [22] to give gold(III) complexes of the type [AuX 3 (L)] (L = imidazolin-2-ylidene or imidazolidin-2ylidene; X = Br, Cl).

Most known gold NHC complexes bear the ubiquitous unsaturated imidazolin-2-ylidenes as carbene ligands, while there are only a few examples for gold complexes bearing benzimidazolin-2-ylidenes [10, 16, 20a-b, 23, 24]. We have been interested in the synthesis and properties of transition metal complexes with benzimidazolin-2-ylidenes for several years [25]. Recently we reported the synthesis and some characteristic properties of gold(I) complexes of the type [AuCl(L)] bearing N,N'-dipropyl-or N,N'-dibutylsubstituted benzimidazolin-2-ylidene ligands [26].

Here we describe the synthesis of gold(I) complexes with N,N'-dialkylated benzimidazolin-2-ylidene ligands and their oxidation with elemental bromine to the gold(III) complexes. The molecular structures of linear gold(I) NHC complexes will be discussed together with the molecular structures of square-planar gold(III) complexes.

Results and Discussion

Gold(I) complexes of the type [AuCl(NHC)] (Scheme 1) were prepared as described [16,26]. The oxidation of these gold(I) chloride complexes with bromine would lead to a mixture of complexes with bromo and chloro ligands. We therefore performed a halide exchange by treatment of the gold(I) chloride complexes with a tenfold excess of lithium bromide in acetone (Scheme 1) following the procedure described by Nolan et al. [21]. The gold(I) bromide complexes 1-4 were obtained in good yields (86-98%) after purification. Although the synthesis of complexes 1 and 2 has already been reported [16], we have listed them here, since we are providing additional analytical data.

Scheme 1. Synthesis of the gold(I) bromide complexes 1-4 by substitution of the chloro ligand.

The 13 C NMR spectra of gold complexes 1-4 exhibit the resonance for the carbene carbon atom in the narrow range of δ 180. 5-181.2. Compared to the resonances of the carbene carbon atoms of the parent gold(I) chloride complexes (δ 178-179) [26] a slight downfield shift (∆δ 2-3) was observed upon the halide exchange, while all other resonances in the 1 H and 13 C NMR spectra remain nearly unchanged. Crystals of 1, 2 and 4, which were suitable for X-ray diffraction studies, have been obtained by slow diffusion of diethyl ether into dichloromethane solutions of the individual complexes. The molecular structures of complexes 1, 2 and 4 are depicted in Figures 1 and2 and selected bond parameters are listed in Table 1. Complexes 1 and 4 reside on general positions in the unit cell, while complex 2 resides on a twofold axis passing through atoms Br, Au and C1. As expected, complexes 1, 2, and 4 exhibit a linear coordination geometry. Two molecules of 1 form a dinuclear species via intermolecular Au•••Au interactions [27] (Au•••Au 3.1179(3) Å, Figure 1, bottom). A similar aurophilic interaction (Au•••Au 3.1216(4) Å) was found for 4 but not for 2. 6)-2.01(3) Å) [16,23,26]. These bond distances are also very close in magnitude to the values observed for Au-C bonds found in complexes of the type [AuBr(imidazolin-2-ylidene)] (1.975 Å) [21]. The Au-Br bond lengths in 1, 2, and 4 also fall in the range previously observed for complexes of the type [AuBr(NHC)] [21]. As expected and previously observed for the parent [AuCl(NHC)] complexes [16,23,26], complexes 1, 2, and 4 exhibit an almost linear C-Au-Br bond. The N-C carbene -N bond angles in the gold(I) complexes are slightly enlarged in comparison to the free benzimidazolin-2-ylidenes (N-C carbene -N ≈ 104°) [28]. [21,22,29] and some authors have tried to explain this observation with the higher Lewis acidity of gold(III) in comparison to gold(I) [21].

Scheme 2. Oxidation of the gold(I) complexes 1-4 with bromine to give the gold(III) complexes 5-8.

Crystals of 6 and 8 suitable for X-ray diffraction studies have been obtained by slow diffusion of diethyl ether into dmf (6) or dichloromethane (8) solutions, respectively, of the complexes. Complex 8 crystallized as 8•0.5CH 2 Cl 2 with two formula units in the asymmetric unit. The two molecules of 8 in the asymmetric unit exhibit essentially identical metric parameters. Only one of these molecules is depicted in Figure 2 together with the molecular structure of 6. Selected bond parameters are summarized in Table 2.

The gold(III) complexes 6 and 8 feature the expected square-planar coordination geometry. The Au-C bonds in 6 (2.003(4) Å) and in the two molecules in 8•0.5CH 2 Cl 2 (2.009(4) Å) are similar in lengths to the equivalent bond distances observed in gold(III) complexes of the type [AuBr 3 (NHC)]

(NHC = imidazolin-2-ylidene or imidazolidin-2-ylidene) (Au-C 2.002(6)-2.052(6) Å) [21,29]. The Au-C distances are very similar in the gold(I) (1, 2, 4) and the gold (III) complexes 6 and 8. The oxidation state of the gold atom apparently bears no significance for the Au-C bond lengths. Due to the trans effect of the carbene donor the Au-Br trans bonds in 6 (2.4465(4) Å) and 8•0.5CH 2 Cl 2 (2.4521(5) Å and 2.4519(5) Å) are longer than the Au-Br cis bonds (2.4107(5)-2.4276(4) Å). These parameters match the equivalent values observed for related gold(III) monocarbene complexes [21,29]. The Au-Br trans bond distances in 6 and 8•0.5CH 2 Cl 2 are significantly longer than the Au-Br distances in 1 (2.4083(4) Å), 2 (2.3910(7) Å), and 4 (2.4065(4) Å) (Table 1). The bond angles in 6 and 8•0.5CH 2 Cl 2 deviate only slightly from the perfect square-planar geometry. The N-C carbene -N bond angles in 6 (108.8(3)°) and 8•0.5CH 2 Cl 2 (108.7(4)° and 109.1(4)°) are slightly larger than the equivalent angles in the parent gold(I) complexes (Table 1).

Conclusions

The synthesis of gold(I) complexes of the type [AuBr(L)] and of gold(III) complexes of the type [AuBr 3 (L)] with L = benzimidazolin-2-ylidene ligands has been described. The gold(I) carbene complexes were obtained from [AuCl(L)] complexes by halide exchange with lithium bromide and the gold(III) complexes have been obtained by oxidation of [AuBr(L)] complexes with elemental bromine. The spectroscopic data for the new gold(I) and gold(III) complexes are in good agreement with equivalent data for related complexes bearing the related imidazolin-2-ylidene and imidazolidin-2-ylidene ligands. The same is true for the metric parameters of the linear complexes of the type [AuBr(L)] and the square-planar complexes of the type [AuBr 3 (L)].

Experimental Section

All operations were carried out in an atmosphere of dry argon by using Schlenk and vacuum techniques. Solvents were dried by standard methods and were freshly distilled prior to use. The (N,N'-dialkylbenzimidazolin-2-ylidene)gold(I) chlorides were prepared using published procedures [16,26]. NMR spectra were recorded on a Bruker Avance I 400 (400 MHz) spectrometer. EI mass spectra were measured on a Varian MAT 212 instrument.

General Procedure for the Synthesis of the (N,N'-Dialkylbenzimidazolin-2-ylidene)gold(I) Bromides (1-4):

A mixture of the (N,N'-dialkylbenzimidazolin-2-ylidene)gold(I) chloride (0.3 mmol) and a tenfold excess of lithium bromide (0.261 g, 3.0 mmol) were dissolved in acetone (10 mL). The reaction mixture was stirred for 24h at ambient temperature. The solvent was the removed in vacuo and the bright yellow residue was dissolved in dichloromethane (30 mL). The solution was dried with magnesium sulfate, filtrated and the solvent was removed in vacuo. The gold(I) complexes were purified by column chromatography (silica gel, dichloromethane), dried in vacuo and were finally obtained as a colorless solid. 7.46 (m,2 H,2 H,, 4.52 (q, 3 J = 7.4 Hz, 4 H, NCH 2 CH 3 ), 1.54 (t, 3 J = 7.4 Hz, 6 H, NCH 2 CH 3 ). 13 C NMR (100.6 MHz, CDCl 3 ): δ = 180.5 (NCN),132.7,124.5,111.4 (Ar-C), 43.8 (NCH 2 CH 3 ), 15.4 (NCH 2 CH 3 ). MS (EI, 20 eV, 200 °C): m/z = 452, 450 (M + ), 371 (M + -Br).

(N,N'-Dipropylbenzimidazolin-2-ylidene)gold(I) Bromide (3): Yield: 0.136 g, 94.9 %. 1 H NMR (400.0 MHz, CD 2 Cl 2 ): δ = 7.50-7.45 (m, 2 H, Ar-H), 7.43-7.39 (m, 2 H, Ar-H), 4.41 (t, 3 J = 7.3 Hz, 4 H, NCH 2 CH 2 CH 3 ), 1.98 (sext, 3 J = 7.3 Hz, 4 H, NCH 2 CH 2 CH 3 ), 0.99 (t, 3 J = 7.3 Hz, 6 H, NCH 2 CH 2 CH 3 ). 13 C NMR (100.6 MHz, CD 2 Cl 2 ): δ = 181.2 (NCN), 133.1,124.4,, 50.2 (NCH 2 CH 2 CH 3 ), 23.3 (NCH 2 CH 2 CH 3 ), 11.3 (NCH 2 CH 2 CH 3 ). MS (EI, 20 eV, 120 °C): m/z = 480, 478 (M + ), 399 (M + -Br).

(N,N'-Dibutylbenzimidazolin-2-ylidene)gold(I) Bromide (4): Yield: 0.149 g, 97.6 %. 1 H NMR (400.0 MHz, CDCl 3 ): δ = 7.49-7.45 (m, 2 H, Ar-H), 7.43-7.39 (m, 2 H, Ar-H), 4.47 (t, 3 J = 7.4 Hz, 4 H, NCH 2 CH 2 CH 2 CH 3 ), 1.93-1.89 (m, 4 H, NCH 2 CH 2 CH 2 CH 3 ), 1.45-1.38 (m, 4 H, NCH 2 CH 2 CH 2 CH 3 ), 0.96 (t, 3 J = 7.4 Hz, 6 H, NCH 2 CH 2 CH 2 CH 3 ). 13 C NMR (100.6 MHz, CDCl 3 ): δ = 181.1 (NCN), 133.0, 124.4, 111.5 (Ar-C), 48.6 (NCH 2 CH 2 CH 2 CH 3 ), 32.0 (NCH 2 CH 2 CH 2 CH 3 ), 20.0 (NCH 2 CH 2 CH 2 CH 3 ), 13.7 (NCH 2 CH 2 CH 2 CH 3 ). MS (EI, 20 eV, 160 °C): m/z = 508, 506 (M + ), 427 (M + -Br).

General Procedure for the Synthesis of the (N,N'-Dialkyl benzimidazolin-2-ylidene)gold(III) Tribromides (5-8): A (N,N'dialkylbenzimidazolin-2-ylidene)gold(I) bromide 1-4 (0.25 mmol) was dissolved in dichloromethane (10 mL). This colorless solution was cooled down to -78 °C, and an excess of bromine (0.03 ml, 0.6 mmol) was added to the solution of the gold(I) complex. The orange solution obtained was stirred for 2 h at -78 °C. Then the solvent was removed in vacuo. The orange residue was dissolved in dichloromethane (5 mL) and dried again in vacuo in order to remove unreacted bromine. This procedure was repeated once more. Finally, the residue was dissolved in dichloromethane (2 mL) and this solution was added to pentane (100 mL). The precipitate obtained was isolated by filtration and dried in vacuo. 2 H,2 H,, 4.49 (q, 3 J = 7.4 Hz, 4 H, NCH 2 CH 3 ), 1.46 (t, 3 J = 7.4 Hz, 6 H, NCH 2 CH 3 ). 4 H,, 4.94 (t, 3 J = 7.9 Hz, 4 H, NCH 2 CH 2 CH 2 CH 3 ), 2.06 (quint, 3 J = 7.7 Hz, 4 H, NCH 2 CH 2 CH 2 CH 3 ), 4.48 (sext, 3 J = 7.4 Hz, 4 H, NCH 2 CH 2 CH 2 CH 3 ), 1.00 (t, 3 J = 7.3 Hz, 6 H, NCH 2 CH 2 CH 2 CH 3 ).

13

C NMR (100.6 MHz, CDCl 3 ): δ = 149.7 (NCN), 133.9, 125.5, 112.1 (Ar-C), 48.5 (NCH 2 CH 2 CH 2 CH 3 ), 30.9 (NCH 2 CH 2 CH 2 CH 3 ), 20.1 (NCH 2 CH 2 CH 2 CH 3 ), 13.6 (NCH 2 CH 2 CH 2 CH 3 ). MS (EI, 20 eV, 220 °C): m/z = 668, 666 (M + ), 506 (M + -2Br), 426 (M + -3Br).

X-ray Diffraction Studies: Diffraction data for 1, 2, 4, 6, and 8•0.5CH 2 Cl 2 were collected with a Bruker AXS APEX CCD diffractometer equipped with a rotation anode using graphitemonochromated Mo-K α radiation (λ = 0.71073 Å) at 153(2) K. Data were collected over the full sphere and were corrected for absorption. Data reduction was performed with the Bruker SMART [30] program package. For further crystal data details see Table 3. Structures solutions were found with the SHELXS-97 [31] package using the heavy-atom method and were refined with SHELXL-97 [32] against F 2 using first isotropic and later anisotropic thermal parameters for all non-hydrogen atoms. Hydrogen atoms were added to the structure models at calculated positions and their thermal parameters were fixed to 1.3 U eqv of the parent atom. Crystallographic data (excluding structure factors) have been deposited with the Cambridge Crystallographic Data Centre as supplementary publications nos. CCDC-778476 (1), CCDC-778477 (2), CCDC-778478 (4), CCDC-778479 (6)

Figure 1 .

 1 Figure 1. Molecular structure of the gold(I) complexes 1 (top) and drawing of the dinuclear species formed by Au•••Au interactions (bottom). Ellipsoids are drawn at the 50 % probability level. Hydrogen atoms are omitted for clarity.

Figure 2 .

 2 Figure 2. Molecular structures of the gold(I) complexes 2 (top) and 4 (bottom). Atoms Au, Br, and C1 of complex 2 lie on a crystallographic twofold axis. Ellipsoids are drawn at the 50 % probability level. Hydrogen atoms are omitted for clarity. The Au-C bond lengths in 1 (1.982(3) Å), 2 (1.989(5) Å) and 4 (1.994(3) Å) are nearly identical to the Au-C separations in the parent monocarbene gold(I) chloride complexes of the type [AuCl(L)] with L = benzimidazolin-2-ylidene (Au-C 1.969(6)-2.01(3) Å)[16,23,26]. These bond distances are also very close in magnitude to the values observed for Au-C bonds found in complexes of the type [AuBr(imidazolin-2-ylidene)] (1.975 Å)[21]. The Au-Br bond lengths in 1, 2, and 4 also fall in the range previously observed for complexes of the type [AuBr(NHC)][21]. As expected and previously observed for the parent [AuCl(NHC)] complexes[16,23,26], complexes 1, 2, and 4 exhibit an almost linear C-Au-Br bond. The N-C carbene -N bond angles in the gold(I) complexes are slightly enlarged in comparison to the free benzimidazolin-2-ylidenes (N-C carbene -N ≈ 104°)[28].

  = Me 2: R = Et 3: R = Pr 4: R = Bu Reaction of the gold complexes 1-4 with elemental bromine in dichloromethane gave the orange gold(III) complexes of the type [AuBr 3 (NHC)] 5-8 with NHC = N,N´-dialkylated benzimidazolin-2-ylidene ligands in good yields (82-89 %, Scheme 2). The 13 C NMR spectra of the gold(III) complexes 5-8 show the resonances of the carbene carbon atoms in the range of δ 146.6-149.7. These values represent an upfield shift (∆δ 31-35) of the C carbene resonance upon oxidation of gold(I) to gold(III). This strong upfield shift is surprising when compared to the downfield shift of ∆δ 1-2 observed for the carbon atoms of the aromatic ring upon the gold(I)→gold(III) oxidation. The resonances observed for C carbene in 5-8, however, resemble the values found for the N-CH-N resonances in the parent benzimidazolium salts (δ 141-144) [25a-c, 25e]. The upfield shift of the C carbene resonance upon the gold(I)→gold(III) oxidation has been observed for related [AuX 3 (NHC)] complexes bearing imidazolin-2-ylidene or imidazolidin-2-ylidene ligands

Figure 3 .

 3 Figure 3. Molecular structures of the gold(III) complexes 6 (top) and 8 in 8•CH 2 Cl 2 (bottom). Ellipsoids are drawn at the 50 % probability level and hydrogen atoms have been omitted for clarity.

  109 g, 85.7 %. 1 H NMR (400.0 MHz, CD 2 Cl 2 ): δ = 7.52-7.44 (m, 4 H, Ar-H), 4.03 (s, 6 H, NCH 3 ). 13 C NMR (100.6 MHz, CD 2 Cl 2 ): δ = 133.1, 124.6, 111.3 (Ar-C), 34.8 (NCH 3 ). The resonance of the carbene carbon atom was not detected. MS (EI, 20 eV, 190 °C): m/z = 424, 422 (M + ), 343 (M + -Br). 124 g, 91.3 %. 1 H NMR (400.0 MHz, CDCl 3 ): δ = 7.51-

  Yield: 0.125 g, 85.7 %. 1 H NMR (400.0 MHz, CD 2 Cl 2 ): δ = 7.62-7.54 (m, 4 H, Ar-H), 4.11 (s, 6 H, NCH 3 ). 13 C NMR (100.6 MHz, CD 2 Cl 2 ): δ = 146.8 (NCN), 134.3, 125.8, 111.6 (Ar-C), 34.8 (NCH 3 ). MS (EI, 20 eV, 160 °C): m/z = 424, 422 (M + -2Br)Yield: 0.125 g, 82.1 %. 1 H NMR (400.0 MHz, [D 6 ]DMSO): δ

13C

  NMR (100.6 MHz, [D 6 ]DMSO): δ = 133.4, 125.5, 112.3 (Ar-C), 43.5 (NCH 2 CH 3 ), 15.2 (NCH 2 CH 3 ). The resonance of the carbene carbon signal was not detected. MS (EI, 20 eV, 200 °C): m/z = 452, 450 (M + -2Br), 371 (M + -3Br). Yield: 0.143g, 89.4 %. 1 H NMR (400.0 MHz, [D 6 ]DMSO): δ = 8.05-7.99 (m, 2 H, Ar-H), 7.59-7.54 (m, 2 H, Ar-H), 4.55 (t, 3 J = 7.6 Hz, 4 H, NCH 2 CH 2 CH 3 ), 2.03 (sext, 3 J = 7.4 Hz, 4 H, NCH 2 CH 2 CH 3 ), 0.98 (t, 3 J = 7.4 Hz, 6 H, NCH 2 CH 2 CH 3 ). 13 C NMR (100.6 MHz, [D 6 ]DMSO): δ = 146.6 (NCN), 133.5, 125.4, 112.8 (Ar-C), 49.3 (NCH 2 CH 2 CH 3 ), 22.0 (NCH 2 CH 2 CH 3 ), 10.8 (NCH 2 CH 2 CH 3 ). MS (EI, 20 eV, 230 °C): m/z = 640, 638 (M + ), 480, 478 (M + -2Br), 399 (M + -3Br). Yield: 0.141 g, 84.3 %. 1 H NMR (400.0 MHz, CDCl 3 ): δ = 7.64.

M

  . C. Jahnke, T. Pape and F. E. Hahn* …….. Page No. -Page No. Synthesis and Characterization of Gold(I) and Gold(III) Complexes Derived from Benzimidazolin-2-ylidene Ligands

Table 1 .

 1 Selected bond lengths (Å) and angles (deg) in complexes 1, 2, and 4.

	Compounds	1	2	4
	Bond lengths
	Au-C1	1.982(3)	1.989(5)	1.994(3)
	Au-Br	2.4083(4)	2.3910(7)	2.4065(4)
	N1-C1	1.352(4)	1.345(4)	1.343(4)
	N2-C1	1.354(4)	-	1.360(4)
	Au•••Au*	3.1179(3)	-	3.1216(4)
	Bond angles
	C1-Au-Br	177.75(10) 180.0	179.30(9)
	N1-C1-N2/	106.3(3)	107.5(4)	106.8(3)
	N1-C1-N1*

Table 2 .

 2 Selected bond lengths (Å) and angles (deg) for 6 and 8•0.5CH 2 Cl 2 .

	Compounds	6	8•0.5CH 2 Cl 2
			molecule A	molecule B
	Bond lengths
	Au1-C1/	2.003(4)	2.009(4)	2.009(4)
	Au2-C21
	Au1-Br3/	2.4107(5)	2.4256(5)	2.4159(5)
	Au2-Br23
	Au1-Br2/	2.4276(4)	2.4109(5)	2.4224(5)
	Au2-Br22
	Au1-Br1/	2.4465(4)	2.4521(5)	2.4519(5)
	Au2-Br21
	N1-C1/	1.348(4)	1.344(5)	1.339(6)
	N21-C21
	N2-C1/	1.346(4)	1.345(5)	1.343(6)
	N22-C21
	Bond angles
	C1-Au1-Br1/	179.01(10) 178.62(12) 179.82(14)
	C21-Au2-Br21
	Br3-Au1-Br2/	176.43(2)	176.34(2)	175.25(2)
	Br23-Au2-Br22
	C1-Au1-Br3/	87.67(10)	88.71(12)	87.51(12)
	C21-Au2-Br23
	C1-Au1-Br2/	88.82(10)	87.79(12)	88.01(12)
	C21-Au2-Br22
	N1-C1-N2/	108.8(3)	108.7(4)	109.1(4)
	N21-C21-N22

Table 3 .

 3 , and CCDC-778480 (8•0.5CH 2 Cl 2 ). Copies of these data can be obtained free of charge on application to CCDC, 12 Union Road, Summary of crystallographic data for 1, 2, 4, 6 and 8•0.5CH 2 Cl 2 . × 0.03 × 0.02 0.38 × 0.12 × 0.08 0.26 × 0.09 × 0.05 0.07 × 0.04 × 0.03 0.20 × 0.11 × 0.09

	Cambridge CB2

Entry for the Table of Contents

Acknowledgement

Financial support by the Deutsche Forschungsgemeinschaft (SFB 858 and IRTG 1444) is gratefully acknowledged.


Hans J Breunig

Mihai G Nema

Cristian Silvestru

Albert Soran

Richard A Varga

n = 1-3) and [2-(Me 2 NCH 2 )C 6 H 4 ]BiBr 2 -new hypervalent organobismuth(III) compounds

Keywords: Bismuth, Hypervalent, NMR studies, X-ray diffraction, Supramolecular Bismuth, Hypervalent, NMR studies, X-ray diffraction, Supramolecular

    [2-{E(CH2CH2)2NCH2}C6H4]nBiX3-n (E = O, NMe; X = Cl, Br, I; n = 1-3) and [2-(Me2NCH2)C6H4]BiBr2 -new hypervalent organobismuth(III) compounds

Introduction

The structural chemistry of organobismuth(III) halides reflects the Lewis amphoteric character of this class of compounds. There are Lewis acidic sites at the bismuth atoms and Lewis basic centres at the halogen atoms. For this reason, the compounds tend to form coordination polymers in the solid state, with trans bismuth-halogen bonds and ψtrigonal bipyramidal coordination, which are poorly soluble in non-polar organic solvents, probably owing to the extended intermolecular association between the bismuth and halogen atoms in the solid state. The intermolecular ____________ * Prof. Dr. Hans J. Breunig interactions involving bismuth play an important role in the construction of supramolecular compounds, e.g. polymeric chains, and two-and three-dimensional structures [START_REF] Whitmire | [END_REF][2][3][4][5][6][START_REF] Uchiyama | [END_REF][8][9][10]. In the case of monoorganobismuth(III) dihalides, it was observed that there is a tendency to form oligomers or polymers which involve one or both halogen atoms. Most of these compounds are insoluble in common solvents due to polymeric associations. Recent developments show that the oligomerization of the organobismuth(III) halides can be overcome at least partially by two strategies. One is the use of bulky substituents which afford isolation of monomeric monohalide species, e.g. [2,4,6-(CF 3 ) 3 C 6 H 2 ] 2 BiCl [11], [(Me 3 Si) 2 CH] 2 BiCl [12], or [2,6-Mes 2 C 6 H 3 ] 2 BiCl [13]. Even with such bulky ligands the dihalides usually form at least dimers, e.g. [2,4,6-Ph 3 C 6 H 2 ]BiCl 2 [8] [14] or [2,6-Mes 2 C 6 H 3 ]BiX 2 (X = Cl [15], Br [16]). Another strategy is to use one pendant arm ligand such as 2-(Me 2 NCH 2 )C 6 H 4 [9] and 2-(Et 2 NCH 2 )C 6 H 4 [17], or "pincer" ligands like 2,6-(Me 2 NCH 2 ) 2 C 6 H 3 [9,18] and 2,6-[MeN(CH 2 CH 2 ) 2 NCH 2 ] 2 C 6 H 3 [18]. These ligands protect the bismuth atom not only sterically by increased coordination, but also reduce considerably the Lewis acidity and consequently the tendency for oligomerization. Indeed, the monohalides [2-(Me 2 NCH 2 )C 6 H 4 ] 2 BiX (X = Cl [19], Br, I [9]), [ [20] are monomeric. The corresponding dihalides usually exhibit low solubility in nonpolar solvents and for [2-(Me 2 NCH 2 )C 6 H 4 ]BiCl 2 a dimer association was described in solid state [9]. Remarkably, the use of the "pincer" ligands 2,6-(Me 2 NCH 2 ) 2 C 6 H 3 and 2,6-[MeN(CH 2 CH 2 ) 2 NCH 2 ] 2 C 6 H 3 afforded monomeric organobismuth(III) dihalides with a T-shaped CBiX 2 core (X = Cl, Br. I) [18,20].

With the aim to increase the sterical protection and to study the influence of the nature of the organic groups on the nitrogen of the pendant arm we have used now the bulkier one pendant arm groups 2-[E(CH 2 CH 2 ) 2 NCH 2 ]C 6 H 4 (E = O, MeN), capable to act as (C,N) ligands. In addition, these groups contain additional donor atoms from the morpholinyl or piperazinyl rings, respectively, available for coordination to other metal centers, which might result in interesting homo-and heterometallic species. We report here the syntheses, structures and spectroscopic properties of compounds (5), Br [START_REF] Uchiyama | [END_REF], I ( 8); E = MeN, X = Cl (6), Br (9), I (10)], as well as [2-(Me 2 NCH 2 )C 6 H 4 ]BiBr 2 (11).

[2-{E(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ] 3 Bi [E = O (1), MeN (2)], [2-{E(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ] 2 BiCl [E = O (3), MeN (4)] and [2-{E(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ]BiX 2 [E = O, X = Cl

Results and Discussion

The homoleptic triorganobismuthanes 1 and 2, the diorganobismuth(III) chlorides 3 and 4 and organobismuth(III) dichlorides 5 and 6 were obtained by reacting the corresponding organolithium derivative with bismuth trichloride in appropriate molar ratios, in diethyl ether, at low temperature (-78 °C). The dibromides 7, 9 and 11, and the diiodides 8 and 10 were obtained by halide exchange reactions starting from the corresponding organobismuth dichloride in dichloromethane and excess aqueous solution of the appropriate potassium halide. The synthetic pathways are depicted in Scheme 1. All compounds were obtained as crystalline solids in fairly good yields and are stable in solid state for more than two months. The triorganobismuthanes 1 and 2 and the monochlorides 3 and 4 are soluble in common organic solvents, while the dihalides 5-11 are well soluble only in DMSO.

Scheme 1. The preparation of compounds 1-10

The solution behavior of the new compounds 1 -11 was investigated by multinuclear ( 1 H, 13 C) NMR spectroscopy, at room temperature. The 1 H and 13 C resonances were assigned using 2D NMR experiments, according to the numbering diagram depicted in Scheme 2. Scheme 2. Numbering scheme for NMR resonance assignments.

The 1 H and 13 C NMR spectra of 1-4, in CDCl 3 , exhibit only one set of resonances for the three, respectively two organic groups attached to a metal atom, thus suggesting their equivalence at the NMR time scale. In absence of an intramolecular N→Bi interaction in solution a fast conformational change of the six-membered morpholinyl and piperazinyl ring, respectively, would result in a pattern of the alkyl region of the [18]. Indeed, the aliphatic regions of the 1 H NMR spectra exhibit only two broad resonance signals for protons H-8,11 and H-9,10 for 1 and 3, and one broad resonance for all protons H-8-11 for 2 and 4, respectively. This suggests that, at room temperature, the intramolecular N→Bi interaction in solution is weak enough to allow a fluxional behaviour. The resonance for the H-7 methylene protons in all compounds 1-4 appears as a singlet.

The dihalides 5, 7 and 8, containing the morpholinylbased ligand, as well as the dibromide 9, exhibit a different pattern in the 1 H NMR spectra at room temperature, i.e. four well separated, multiplet resonances for the methylene protons of the morpholinyl / piperazinyl ring. This behaviour is not so evident for the dichloride 6 and the diiodide 10, containing the pyperazinyl-based ligand, the resonances being in these cases considerably overlapped. The non-equivalence of these protons is consistent with the presence of a strong intramolecular N→Bi interaction in solution, at room temperature, as found in solid state (see subsequent discussion). Such an interaction will prevent a fluxional process and the conformational change of the sixmembered morpholinyl and piperazinyl ring. A similar behaviour was reported for organoselenium derivatives containing the same pendant arm ligands [22] and the related dihalides [2,6-{MeN(CH 2 CH 2 ) 2 NCH 2 } 2 C 6 H 3 ]BiX 2 [18]. As a result of the intramolecular N→Bi interaction the H-8,11 (N-CH 2 -CH 2 -E) and H-9,10 (N-CH 2 -CH 2 -E) protons became non-equivalent, i.e. pro-cis and pro-trans with respect to the position of the bismuth atom in relation to the morpholinyl / piperazinyl ring (see also ref. 18). Thus, the room-temperature 1 H NMR data for these dihalides provided evidences for the presence of the intramolecular N→Bi interactions in solution, the inversion at the nitrogen atom being frozen at this temperature.

Single crystals suitable for X-ray diffraction were obtained by slow diffusion of n-hexane into a CH 2 Cl 2 solution for 1-4, while crystals of the dihalides 5 and 11 were obtained from a concentrated solution in DMSO.

The molecular structure of 1 is depicted in Figure 1 and selected interatomic distances and angles for both 1 and 2 are listed in Table 1 (see Supporting information for the molecular structure of 2). Table 1. Selected bond lengths /Å and angles /º for compounds 1 and 2 as determined by single-crystal X-ray diffraction.

1 [a]
2 [a] Bi Bi(1)-N(1)-C(7) 82.9(3) 81.9(2) [a] Symmetry equivalent atoms are given by "a" (1 -x + y, 1 -x, z) and "b" (1 -y, x -y, z).

The crystals of both compounds belong to the R-3 rhombohedral system and contain highly symmetric discrete molecules, with no further intermolecular interactions between heavy atoms. In both molecules 1 and 2 the bismuth atom resides on a 3-fold axis which relates the three aryl substituents in a propeller-like conformation similar to that found in [2-(R 2 NCH 2 )C 6 H 4 ] 3 Bi (R = Me [23], Et [17]). The nitrogen atoms coordinate weakly to bismuth [Bi(1)-N( 1 Bi core] and the compounds can be described as a hypervalent 14-Bi-6 species [START_REF]Chemistry of Hypervalent Compounds[END_REF][START_REF] Perkins | The N-X-L nomenclature system has been previously described: N valence shell electrons about a central atom X with L ligands[END_REF]. The morpholinyl and piperazinyl rings exhibit a chair conformation which prevents further intramolecular coordination to the bismuth atoms.

The nonplanarity of the five-membered BiC 3 N rings induces planar chirality (with the aromatic ring and the nitrogen atom as chiral plane and pilot atom, respectively; isomers given as S N and R N ) [START_REF]Nomenclature of Organic Chemistry -The Blue Book[END_REF] and the crystals of the triorganobismuthanes 1 and 2 contain a 1:1 mixture of all-R N and all-S N isomers (see Supporting information).

The crystals of monochlorides 3 and 4 contain one independent molecule in the asymmetric unit. The molecular structure of 4 is depicted in Figure 2 (see Supporting information for the molecular structure of 3) and selected interatomic distances and angles are listed in Table 2. 6) Å] [17]. The N→Bi interaction trans to the carbon atom is considerably shorter than in the related triorganobismuthanes (see Table 1), but of the same magnitude as in The molecules of 3 and 4 contain two five-membered BiC 3 N rings folded along the Bi⋅⋅⋅C methylene axis, with the nitrogen atom lying out of the best plane defined by the residual BiC 3 fragment. This induces planar chirality [START_REF]Nomenclature of Organic Chemistry -The Blue Book[END_REF]. Moreover, chirality at the bismuth atom is also induced, at least in solid state, since the same organic groups attached to the metal become non-equivalent as result of the intramolecular N→Bi interactions: the aryl moiety of one ligand is placed in the apical position of the square pyramidal (C,N) 2 BiCl core and its nitrogen atom is coordinated in the basal plane trans the Bi-C bond established by the other pendant arm organic group, which, subsequently, has both its carbon atom attached to the metal and its nitrogen atom in the basal plane, coordinated trans to the chlorine atom. This "chelate-induced" chirality [29] at the Bi atom in the square pyramidal environment can be described in term of C Bi and A Bi isomers [START_REF]Nomenclature of Inorganic Chemistry -IUPAC Recommendations 2005[END_REF]. Indeed, the crystals of 3 and 4 contain a 1:1 mixture of (R N1 ,S N2 ,C Bi ) / (S N1 ,R N2 ,A Bi )-3 isomers and (S N1 ,R N2 ,C Bi ) / (R N1 ,S N2 ,A Bi )-4 isomers (with respect to the two chelate rings at a metal atom), respectively.

The structures of the dihalides 5 and 11 are depicted in Figures 3 and4. Relevant interatomic distances and angles are listed in Table 3. Table 3. Selected bond lengths /Å and angles /º for compounds 5 and 11 as determined by single-crystal X-ray diffraction. [a] 5 [b] 11 [b] Bi -x, 1y,-z), (-x, 0.5 + y, 0.5z), (x, 1.5y, -0.5 + z), (x, 0.5y, -0.5 + z) and (-x, -0.5 + y, 0.5z) are given by ''prime'', ''prime a'', ''b', "c" and ''prime d'', respectively]. [19].

Conclusions

Room temperature 1 H, 13 C and 2D NMR spectra were recorded in dried CDCl 3 [START_REF] Whitmire | [END_REF](2)(3)(4) or DMSO-d 6 (5)(6)[START_REF] Uchiyama | [END_REF](8)(9)(10)(11), on Bruker Avance 300, Bruker Avance DPX 200 or Bruker Avance WB 360 instruments. The chemical shifts are reported in ppm relative to the residual peak of the solvent (ref. CHCl 3 : 1 H 7.26, 13 C 77.0 ppm; DMSO-d 5 : 1 H 2.50, 13 C 39.43 ppm). The NMR spectra were processed using the MestReC and MestReNova software [START_REF] Mestrec | A Coruña 15706[END_REF]. Mass spectra were recorded with Finnigan MAT 8200 instrument and were processed using the MASPEC II software [START_REF]MASPEC II Data System[END_REF].

The details of the crystal structure determination and refinement for compounds 1-5 and 11 are given in Table 4. Data were collected on Bruker SMART APEX (1, 2, 4, 5, 11) and Siemens P4 (3) diffractometers, using graphite-monochromated Mo-Kα radiation (λ = 0.71073 Å). For this purpose the crystals were attached with epoxy glue on cryoloops and the data were collected at room temperature (297 K) and 173 K (cooled under a nitrogen stream), respectively. The structures were refined with anisotropic thermal parameters. The hydrogen atoms were refined with a riding model and a mutual isotropic thermal parameter. For structure solving and refinement the software package SHELX-97 was used [START_REF] Sheldrick | [END_REF]. The drawings were created with the Diamond program [START_REF]DIAMOND -Visual Crystal Structure Information System, Crystal Impact[END_REF].

Crystallographic data (excluding structure factors) for the structures reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC 778940 -778945. Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK [Fax.: + 44-1223-336-033; E-mail: deposit@ccdc.cam.ac.uk].

Synthesis of [2-{O(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ] 3 Bi (1)

A solution of n-BuLi in n-hexane (14.64 mL 1.6 M, 23.43 mmol) was added dropwise to a stirred solution of 2-[O(CH 2 CH 2 ) 2 NCH 2 ]C 6 H 4 Br (6.0 g, 23.43 mmol) in 100 mL anhydrous n-hexane, at room temperature, under argon. The reaction mixture was stirred for 2 h. Evaporation of the solvent gave [2-{O(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ]Li as a white compound. To the solid product suspended in 100 mL anhydrous diethyl ether was added, at -78 ºC, a solution of BiCl 3 (2.45 g, 7.79 mmol) in 50 mL diethyl ether. The reaction temperature was maintained at -78 ºC for 2 h, following which the reaction mixture was allowed to warm slowly to ambient temperature. After being stirred for additional 12 h, the reaction mixture was filtered and the solvent was evaporated in vacuum to give 1 as a white-grey solid (4.09 g, 71% yield). M.p.: 239 ºC. Anal. calcd. (found) for C [START_REF] Mestrec | A Coruña 15706[END_REF] 3 J HH = 7.1 Hz). 13

Synthesis of [2-{MeN(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ] 3 Bi (2)

A solution of n-BuLi in n-hexane (5.66 3 J HH = 6.8 Hz). 13 [R 2 Bi] + , 398 (10) [RBi] + , 209 (11) [Bi] + , 189 [START_REF] Suzuki | [END_REF]

[R] + [R = 2-{MeN(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ].

Synthesis of [2-{O(CH

Synthesis of [2-{MeN(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ]BiCl 2 (6)

A suspension of [2- 3 J HH = 6.9 Hz), 7.69 (t, 1H, H-5, 3 J HH = 7.2 Hz), 7.83 (d, 1H, H-3, 3 J HH = 7.4 Hz), 9.18 (d, 1H, H-6, 3 J HH = 7.5 Hz). 13

Figure 1

 1 Figure 1. The molecular structure of [2-{O(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ] 3 Bi (1) [(all-R N ) isomer] (thermal ellipsoids are represented at 30% probability level; hydrogen atoms are omitted for clarity).

  ) 3.170(7) Å for 1 and 3.211(5) Å for 2, respectively; c.f. the sum of covalent and van der Waals radii for nitrogen and bismuth; Σr cov (Bi,N) 2.27 Å and Σr vdW (Bi,N) 3.94 Å] [24] almost trans to a Bi-C bond [N(1)-Bi(1)-C(1a) 157.3(2)º and 156.3(1)º for 1 and 2, respectively]. The Bi-N bond lengths are considerably longer than those reported for [2-(Me 2 NCH 2 )C 6 H 4 ] 3 Bi [3.04(2)-3.11(3) Å] [23], a behaviour which could be attributed to combined electronic and steric effects of the morpholinyl / piperazinyl groups as was found for the related [2-(Et 2 NCH 2 )C 6 H 4 ] 3 Bi [3.214(7) Å] [17]. The coordination geometry at the bismuth atom, taking into account the intramolecular N→Bi interactions, is distorted octahedral [(C,N) 3

  Figure 2. The molecular structure of [2-{MeN(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ] 2 BiCl (4) [(R N1 ,S N2 ,A Bi ) isomer] (thermal ellipsoids are represented at 30% probability level; hydrogen atoms are omitted for clarity).

  (1)-X(2) 3.095(11) 3.061(14) C(1)-Bi(1)-X(1) 91.3(5) 94.7(6) C(1)-Bi(1)-Cl(1) 90.6(4) 92.5(4) X(1)-Bi(1)-Cl(1) 93.5(3) 90.6(4) N(1)-Bi(1)-C(1) 70.4(4) 69.3(5) N(1)-Bi(1)-X(1) 88.2(4) 98.1(5) N(1)-Bi(1)-Cl(1) 161.0(2) 160.3(3) N(1)-Bi(1)-X(2) 110.2(3) 115.7(4) X(2)-Bi(1)-C(1) 155.0(4) 162.7(5) X(2)-Bi(1)-X(1) 63.9(4) 68.5(5) X(2)-Bi(1)-Cl(1) 87.4(2) 83.9(3) Bi(1)-N(1)-C(7) 100.0(7) 92.9(10) Bi(1)-X(2)-X(3) 88.6(7) 90.5(10) [a] X(1), X(2) and X(3) are C(12), N(2) and C(18) for 3, and C(13), N(3) and C(19) for 4. is longer than in [2-(Me 2 NCH 2 )C 6 H 4 ] 2 BiCl [2.570(5) Å] [19], but close to that observed for the ethyl analogue [2-(Et 2 NCH 2 )C 6 H 4 ] 2 BiCl [2.645(

  [2-(R 2 NCH 2 )C 6 H 4 ] 2 BiCl [3.047(5) Å for R = Me [19]; 3.056(7) Å for R = Et [17]]. The overall molecular structures of the monochlorides 3 and 4 are thus very similar to those reported for the related [2-(R 2 NCH 2 )C 6 H 4 ] 2 BiCl and, taking into account both intramolecular N→Bi interactions per metal atom, the coordination geometry features distorted square-pyramidal [(C,N) 2 BiCl cores; hypervalent 12-Bi-5 species [25,26]], with an aromatic carbon atom in apical position. The deviations of the bond angles at the metal atom from the ideal values are mainly due to the constraints imposed by the coordinated nitrogen atoms. The bismuth-chlorine bond lengths are different in 3 [2.623(4) Å] and 4 [2.733(3) Å], but in the range observed for related compounds, e.g. [2-(R 2 NCH 2 )C 6 H 4 ] 2 BiCl [2.667(2) Å for R = Me [19]; 2.602(2) Å for R = Et [17]) or [2-(Me 2 NCH 2 )C 6 H 4 ](4-MeC 6 H 4 )BiCl [2.700(2) Ǻ] [28]. The elongation of the Bi-Cl bond in these hypervalent species with respect to the values observed in tricoordinated monochlorides, e.g. [2,4,6-(CF 3 )C 6 H 2 ] 2 BiCl [2.463(3) Å] [11], is apparently a consequence of the coordination of the amino group trans to the halogen atom.

Figure 3 .

 3 Figure 3. Dimer association between (S N1 ,A Bi1 ) and (R N1' ,C Bi1' ) isomers in the crystal of [2-{O(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ]BiCl 2 (5) (thermal ellipsoids are represented at 30% probability level; hydrogen atoms are omitted for clarity).

Figure 4 .

 4 Figure 4. Dimer association between (R N1 ,A Bi1 ) and (S N1' ,C Bi1' ) isomers in the crystal of [2-(Me 2 NCH 2 )C 6 H 4 ]BiBr 2 (11) (thermal ellipsoids are represented at 30% probability level; hydrogen atoms are omitted for clarity).

  1)-C(1) 2.209(12) 2.214(15) Bi(1)-X[START_REF] Whitmire | [END_REF] 2.720(3) 2.9378(18) The crystals of both compounds consist of centrosymmetric dimers in which (S N1 ,A Bi1 )-and (R N1' ,C Bi1' )-5 isomers and (R N1 ,A Bi1 )-and (S N1' ,C Bi1' )-11 isomers, respectively, are connected through bridging halogen atoms. Similar dimers were reported for the related [2-(Me 2 NCH 2 )C 6 H 4 ]BiX 2 (X = Cl[9], I[19]). The nitrogen of the pendant arm is strongly coordinated to the metal [N(1)-Bi(1) 2.548(9) Å for 5 and 2.485(13) for 11] in trans to the bridging halogen atom. The main difference resides in the extent of asymmetry of the Bi-X-Bi bridges, larger for the dichloride 5 [Bi(1)-Cl(1) 2.720(3) Å, Bi(1')-Cl(1) 3.021(4) Å] than for the dibromide 11 [Bi(1)-Br(1) 2.9378(18) Å, Bi(1')-Br(1) 3.0695(19) Å]. As expected, the Bi-X bonds in the planar Bi 2 X 2 fragment are considerably longer than the terminal bismuth-halogen bond [Bi(1)-Cl(2) 2.527(4) Å for 5 and Bi(1)-Br(2) 2.720(2) for 11, respectively]. The geometry at bismuth is best described as distorted square-based pyramidal with the aryl group in the apical position and the three chlorides and the nitrogen atom of the amine arm in the basal plane [(C,N)BiX 3 cores; hypervalent 12-Bi-5 species [25,26]]. A closer check of the crystal packing revealed that for the triorganobismuthanes 1 and 2 and the monochloride 4 there are no intermolecular interactions. By contrast, for the monochloride 3 there are weak intermolecular Cl•••H contacts close to the sum of corresponding van der Waals radii [Σr vdW (Cl,H) ca. 3.0 Å] [24], which result in supramolecular architectures. Ribbon-like polymers of (R N1 ,S N2 ,C Bi )-3 and (S N1 ,R N2 ,A Bi )-3 isomers, respectively, are established through weak Cl•••H aryl [Cl(1)•••H(15b) 2.93 Å] and Cl•••H morpholinyl [Cl(1)•••H(10Aa) 2.95 Å] contacts. Additional weak Cl•••H morpholinyl [Cl(1)•••H(19Bb') 2.99 Å] contacts between parallel polymers extended along the a axis result in a waved layer. No further contacts are established between the layers (see Supporting information). As described previously for the related [2-(Me 2 NCH 2 )C 6 H 4 ]BiX 2 (X = Cl [9], I [19]), in the crystals of 11 the dimer units are further associated through weaker Bi(1)•••Br(2'a) interactions [3.778(5) Å; c.f. Σr vdW (Bi,Br) 4.35 Å] [24] into a ribbon-like polymer along the a axis. If these interactions are considered, the overall Bi coordination geometry in 11 is distorted octahedral (Figure 5). Further weak inter-chain Br•••H contacts result in a 3D architecture (see Supporting information). By contrast, the metal atoms in the dimer of 5 are better sterically protected and no association through Bi•••Cl interactions were observed. However, quite strong Cl•••H aryl [Cl(2)•••H(4b) 2.74 Å] interactions result in a layer structure, each dimer unit being connected to four other dimer fragments (Figure 6).

Figure 5 .

 5 Figure 5. Ribbon-like polymer in the crystal of [2-(Me 2 NCH 2 )C 6 H 4 ]BiBr 2 (11) [symmetry equivalent atoms (1x, -y, 2z), (-x, -y, 2z) and (1 + x, y, z) are given by ''prime'', ''prime a'' and ''b'', respectively].

Figure 6 .

 6 Figure 6. View along a axis of a fragment from the layer of dimers in the crystal of [2-{O(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ]BiCl 2 (5) [symmetry equivalent atoms (-x, 1y,-z), (-x, 0.5 + y, 0.5z), (x, 1.5y, -0.5 + z), (x, 0.5y, -0.5 + z) and (-x, -0.5 + y, 0.5z) are given by ''prime'', ''prime a'', ''b', "c" and ''prime d'', respectively].

  C NMR (CDCl 3 , 75.5 MHz): δ 53.42 (s, C-8,11), 66.23 (s, C-9,10), 67.90 (s, C-7), 126.73 (s, C-4), 129.67 (s, C-5), 129.99 (s, C-3), 139.81 (s, C-6), 142.90 (s, C-2), 163.53 (s, C-1). MS-EI 70 eV (200 ºC) m/z (rel. int. %), 736 (5) [M] + , 561 (100) [R 2 Bi] + , 209 (5) [Bi] + , 176 (20) [R] + [R = 2-{O(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ].

  C NMR (CDCl 3 , 50.3 MHz): δ 45.93 (s, NCH 3 ), 53.01 (s, C-9,10), 54.20 (s, C-8,11), 67.57 (s, C-7), 126.42 (s, C-4), 129.49 (s, C-5), 129.53 (s, C-3), 139.96 (s, C-6), 143.66 (s, C-2), 164.32 (s, C-1). MS-EI 70 eV (200 ºC) m/z (rel. int. %), 587 (100)

≈ 3 J

 3 HH = 11 Hz], 3.79 [d, 2H, H pro-cis -9,10, 2 J HH = 12.2 Hz], 4.27 (s, 2H, H-7), 7.41 (t, 1H, H-4, 3 J HH = 7.4 Hz), 7.67 (t, 1H, H-5, 3 J HH = 7.4 Hz), 7.81 (d, 1H, H-3, 3 J HH = 7.5 Hz), 9.16 (d, 1H, H-6, 3 J HH = 7.5 Hz). 13 C NMR (DMSO-d 6 , 50.3 MHz): δ 53.76 (s, C-8,11), 66.91 (s, C-9,10), 68.10 (s, C-7), 127.77 (s, C-4), 129.73 (s, C-3), 131.08 (s, C-5), 139.51 (s, C-6), 148.38 (s, C-2), 211.47 (s, C-1). MS-EI 70 eV (200 ºC) m/z (rel. int. %), 455 (20) [M] + , 420 (60) [M-Cl] + , 209 (24) [Bi] + , 176 (38) [R] + [R = 2-{O(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ].

  C NMR (DMSO-d 6 , 50.3 MHz): δ 42.14 (s, NCH 3 ), 50.42 (s, C-9,10), 52.57 (s, C-8,11), 66.54 (s, C-7), 127.48 (s, C-4), 129.82 (s, C-3), 131.22 (s, C-5), 139.35 (s, C-6), 147.54 (s, C-2), 214.61 (s, C-1). MS-EI 70 eV (200 ºC) m/z (rel. int. %), 434 (30) [M-Cl] + , 398

  2-(Et 2 NCH 2 )C 6 H 4 ] 2 BiX [17] and [2,6-(Me 2 NCH 2 ) 2 C 6 H 3 ] 2 BiCl

  CH 2 CH 2 ) 2 NCH 2 ] 2 C 6 H 4

				1 H spectrum similar with that
	observed	for	the	free	organic	ligands	2-
	[O(CH 2 CH 2 ) 2 NCH 2 ]C 6 H 4 Br	[21]	and	2-
	[MeN(CH 2 CH 2 ) 2 NCH 2 ]C 6 H 4 Br	or	the	1,3-
	[MeN(

Table 2 .

 2 Selected bond lengths /Å and angles /º for compounds 3 and 4 as determined by single-crystal X-ray diffraction.[a]

	3	4

Table 4 .

 4 X-ray crystallographic data for 1-5 and 11.

	New bismuth compounds of the types [2-
	{E(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ] 3 Bi,		[2-
	{E(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ] 2 BiCl	and	[2-
	{E(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ]BiX 2 (E = O, MeN; X = Cl, Br, I),
	as well as [2-(Me 2 NCH 2 )C 6 H 4 ]BiBr 2 were prepared and
	their structures were investigated both in solution and in

  H 42 BiN 3 O 3 : C 53.73 (53.94) %; H 5.74 (5.65) %; N 5.70 (5.59) %. 1 H NMR (CDCl 3 , 300 MHz): δ 2.26 (s,br, 12H, H-8,11), 3.00 (s,br, 12H, H-9,10), 3.58 (s,br, 6H, H-7), 7.08 (t, 3H, H-5, 3 J HH = 7.1 Hz), 7.21 (t, 3H, H-4, 3 J HH = 7.2 Hz), 7.26 (d, 3H, H-3, 3 J HH = 7.7 Hz), 7.64 (d, 3H, H-6,

  CH 2 CH 2 ) 2 NCH 2 ]C 6 H 4 Br (2.47 g, 9.18 mmol) in 100 mL anhydrous n-hexane, at room temperature, under argon. After 30 minutes a white precipitate was formed. The reaction mixture was stirred for 4 h. Evaporation of the solvent gave [2-{MeN(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ]Li as a white compound. To the suspension of the solid product in 100 mL anhydrous diethyl ether was added, at -78 ºC, a solution of BiCl 3 (0.95 g, 3.02 mmol) in 50 mL diethyl ether. The reaction mixture was stirred for 1 h at -78 ºC, then allowed to reach room temperature and filtered through a glass frit under argon atmosphere. The solution was evaporated under vacuum to give 2 as a white solid (1.0 g, 43% yield). M.p.: 205 ºC. Anal. calcd. (found) for C 36 H 51 BiN 6 : C 55.66 (55.96) %; H 6.62 (6.44) %; N 10.82 (10.94) %. 1 H NMR (CDCl 3 , 200 MHz): δ 1.95 (s, 9H, NCH 3 ), 2.30 (s,br, 24H, H-8-11), 3.58 (s,br, 6H, H-7),

					mL 1.6 M, 9.18 mmol) was
	added	dropwise	to	a	stirred	solution	of	2-
	[MeN(7.06 (t, 3H, H-5, 3 J HH = 7.2 Hz), 7.19 (t, 3H, H-4, 3 J HH = 7.2 Hz),
	7.24 (m, 3H, H-3), 7.71 (d, 3H, H-6,

2 CH 2 ) 2 NCH 2 }C 6 H 4 ] 2 BiCl (3) A suspension

  of [2-{O(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ]Li [obtained from n-BuLi in n-hexane (14.65 mL 1.6 M, 23.43 mmol) and 2-[O(CH 2 CH 2 ) 2 NCH 2 ]C 6 H 4 Br (6.0 g, 23.43 mmol)] in 100 mL anhydrous diethyl ether was added dropwise, at -78 ºC, to a solution of BiCl 3 (3.69 g, 11.71 mmol) in 50 mL diethyl ether. The reaction mixture was allowed to reach room temperature over night and then filtered through a glass frit. The white solid retained on the frit was extracted with 2 x 50 mL of chloroform and evaporation of the clear solution gave 3 as a fade yellowish solid C-7), 128.44 (s, C-4), 130.31 (s, C-3), 131.52 (s, C-5), 140.46 (s, C-6), 144.21 (s, C-2), 181.57 (s, C-1). MS-EI 70 eV (200 ºC) m/z (rel. int. %), 561 (100) [M-Cl] + , 420 (20) [M-R] + , 385 (19) [RBi] + , 209 (28) [Bi] + , 176 (80) [R] + [R = 2-{O(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ].

	(4.61 g, 66% yield). M.p.: 195 ºC. Anal. calcd. (found) for
	C 22 H 28 BiClN 2 O 2 : C 44.27 (44.11) %; H 4.73 (4.75) %; N 4.69
	(4.66) %. 1 H NMR (CDCl 3 , 300 MHz): δ 2.55 (s,br, 8H, H-8,11),
	3.68 (s, 4H, H-7), 3.79 (s,br, 8H, H-9,10), 7.41 (m, 4H, H-4,5),
	7.52 (d, 2H, H-3, 3 J HH = 6.9 Hz), 8.57 (d, 2H, H-6, 3 J HH = 7.3 Hz).
	13 C NMR (CDCl 3 , 75.5 MHz): δ 53.88 (s, C-8,11), 66.95 (s, C-
	9,10), 67.74 (s, Synthesis

of [2-{MeN(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ] 2 BiCl (4)

  A suspension of[2-{MeN(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ]Li [obtained from n-BuLi in n-hexane (5.66 mL 1.6 M, 9.18 mmol) and 2-[MeN(CH 2 CH 2 ) 2 NCH 2 ]C 6 H 4 Br (2.47 g, 9.18 mmol)] in 100 mL anhydrous diethyl ether was added dropwise, at -78 ºC, to a solution of BiCl 3 (1.42 g, 4.57 mmol) in 50 mL diethyl ether. The reaction mixture was stirred for 1 h at -78 ºC, then 12 h to reach the room temperature. It was filtered under argon atmosphere and the solution was evaporated under vacuum to give 4 as a whiteyellow solid (2.33 g, 82% yield). M.p.: 179 ºC. Anal. calcd. Bi] + , 189 (30) [R] + [R = 2-{MeN(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ].

	(found) for C 24 H 34 BiClN 4 : C 46.27 (46.72) %; H 5.50 (5.72) %; N
	8.99 (9.26) %. 1 H NMR (CDCl 3 , 200 MHz): δ 2.32 (s, 6H, NCH 3 ),
	2.56 (s,br, 16H, H-8-11), 3.69 (s,br, 4H, H-7), 7.39 (m, 4H, H-4,5),
	7.51 (d, 2H, H-3, 3 J HH = 6.8 Hz), 8.65 (d,br, 2H, H-6). 13 C NMR
	(CDCl 3 , 50.3 MHz): δ 46.01 (s, NCH 3 ), 53.61 (s, C-9,10), 55.14 (s,
	C-8,11), 67.23 (s, C-7), 128.25 (s, C-4), 130.09 (s, C-3), 131.41 (s,
	C-5), 141.32 (s, C-6), 144.89 (s, C-2), 178.93 (s, C-1). MS-EI 70
	eV (200 ºC) m/z (rel. int. %), 586 (8) [M-Cl] + , 432 (27) [M-R] + ,
	209 (11) [Synthesis of [2

-{O(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ]BiCl 2 (5)

  A suspension of [2-{O(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ]Li [obtained from n-BuLi in n-hexane (7.32 mL 1.6 M, 11.71 mmol) and 2-[O(CH 2 CH 2 ) 2 NCH 2 ]C 6 H 4 Br (3.0 g, 11.71 mmol)] in 60 mL anhydrous diethyl ether was added dropwise, at -78 ºC, to a solution of BiCl 3 (3.69 g, 11.71 mmol) in 30 mL diethyl ether. The reaction mixture was stirred for 2 h at -78 ºC, then allowed to reach room temperature and filtered through a glass frit. The white solid retained on the frit was washed with 25 mL of n-hexane, then dried to give 5 as a white solid (3.99 g, 75% yield). M.p.: 145 ºC (dec.). Anal. calcd. (found) for C 11 H 14 BiCl 2 NO: C 28.97 (28.67) %; H 3.09 (3.48) %; N 3.07 (3.03) %. 1 H NMR (DMSO-d 6 , 360 MHz): δ 2.58 [t, 2H, H pro-trans -8,11, 2 J HH ≈ 3 J HH = 11.7 Hz], 3.26 [d, 2H, H pro-cis -8,11, 2 J HH = 12.1 Hz], 3.67 [t, 2H, H pro-trans -9,10, 2 J HH

  {MeN(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ]Li [obtained from n-BuLi in n-hexane (12.50 mL 1.6 M, 20 mmol) and 2-[MeN(CH 2 CH 2 ) 2 NCH 2 ]C 6 H 4 Br (5.38 g, 20 mmol)] in 50 mL anhydrous diethyl ether was added dropwise with stirring, at -78 ºC, to a solution of BiCl 3 (6.31 g, 20 mmol) in 40 mL diethyl ether. The reaction mixture was stirred for 1 h at -78 ºC, then over night to reach room temperature. It was filtered and the remaining white residue was washed with 25 mL n-hexane and dried under vacuum to give 8 as a white solid (8.44 g, 90% yield). M.p.: 195 ºC (dec). Anal. calcd. (found) for C 12 H 17 BiCl 2 N 2 : C 30.72 (30.36) %; H 3.65 (3.72) %; N 5.97 (5.56) %. 1 H NMR (DMSO-d 6 , 360 MHz): δ 2.68 (s,br, 3H, NCH 3 ), 3.41 (br, 8H, H-8-11), 4.27 (s, 2H, H-7), 7.42 (t, 1H, H-4,

Acknowledgement Financial support from National University Research Council (CNCSIS, Romania; Research Project No. PNII-ID 2052/2009) is greatly appreciated. We also thank Deutsche Forschungsgemeinschaft and DAAD for financial support and Universität Bremen for providing research facilities during research stays of M.G.N. and C.S. The support provided by the NATIONAL CENTER FOR X-RAY DIFFRACTION (Babes-Bolyai University, Cluj-Napoca, Romania) for the solid state structure determinations is highly acknowledged.

Synthesis of [2-{MeN(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ]BiBr 2 (9)

A suspension of 6 (0.50 g, 1.06 mmol) in 50 mL methylene chloride was vigorously stirred for 24 h with a solution of KBr (0.38 g, 3.19 mmol) in 25 mL distilled water. The reaction mixture was filtered off and the precipitate was dried in vacuum to give compound 9 as a white powder (0.38 g, 65% yield). M.p.: 205 ºC (dec. 3 J HH = 6.9 Hz), 7.91 (d, 1H, H-3, 3 J HH = 7.2 Hz), 9.47 (d, 1H, H-6, 3 J HH = 7.3 Hz). 13 int. %), 558 (20) [M] + , 477 (100) [M-Br] + , 268 (22) [RBr] + , 209 (44) [Bi] + , 189 (21)

Synthesis of [2-{MeN(CH 2 CH 2 ) 2 NCH 2 }C 6 H 4 ]BiI 2 (10)

Compound 10 was prepared similar to 9, from a suspension of 6 (0.50 g, 1.06 mmol) in 50 mL methylene chloride and a solution of KI (0.53 g, 3.19 mmol) in 25 mL distilled water, as an orange powder (0.54 g, 78% yield). M.p.: 156 ºC (dec. 3 J HH = 7.4 Hz). 13


Dr Ralph Puchta
email: ralph.puchta@chemie.uni-erlangen.de

René Kolbig

Frank Weller

Bernhard Neumüller

Werner Massa

Dr Kurt Dehnicke
email: dehnicke@chemie.uni-marburg.de

-Krone-6)] und sein Hydrolyseprodukt [{Be 3 (µ-OH) 3 (H 2 O) 6 }(18-Krone-6)]Cl 3 ⋅ ⋅ ⋅ ⋅3H 2 O: Kristallstrukturen und DFT-Rechnungen [(BeCl 2 ) 2 (18-Crown-6)] and its Product of Hydrolysis [{Be 3 (µ-OH) 3 (H 2 O) 6 }(18-Crown-6)]Cl 3 ⋅3H 2 O: Crystal Structures and DFT Calculations

Keywords: Beryllium, Crown ether complex, Hydroxo complex, Crystal structures, Vibrational spectra, DFT calculations Beryllium, Crown ether complex, Hydroxo complex, Crystal structures, Vibrational spectra, DFT calculations

BeCl 2 ) 2 (18-Krone-6)] und sein Hydrolyseprodukt [{Be 3 (µ-OH) 3 (H 2 O) 6 }

Exposition of 1 to moist atmosphere leads to single crystals of [{Be 3 (µ-OH) 3 (H 2 O) 6 }(18-crown-6)]Cl 3 ⋅3H 2 O (2⋅3H 2 O), which are characterized by X-ray diffraction. 2 crystallizes in the triclinic space group P1 with Z = 2. Lattice dimensions at 100(2) K: a = 1046.04 (9), b = 1236.12 (11), c = 1275.72 (13) deposit@ccdc.cam.ac.uk), Großbritannien, angefordert werden).

Kristallstruktur von [(BeCl

Experimenteller Teil

Vorsicht! Beryllium und seine Verbindungen sind stark toxisch (MAK-Liste A2 krebserregender Arbeitsstoffe; siehe auch die Literatur in der Übersicht [1]). Es wirkt zudem auch mutagen [START_REF] Kaim | Bioanorganische Chemie[END_REF]. Der Umgang mit Berylliumverbindungen erfordert daher die Anwendung besonderer Arbeitsbedingungen. Siehe hierzu die aktuelle Übersicht aus arbeitsmedizinischer Sicht [START_REF] Schaller | Handbuch der Arbeitsmedizin[END_REF].

Ein Teil der Versuche erfordert Ausschluß von Feuchtigkeit. Berylliumchlorid erhielten wir wie beschrieben [START_REF] Neumüller | [END_REF]

1 Einleitung

 1 pm, α = 80.233(8)°, β = 66.439(7)°, γ = 80.053(7)°, R 1 = 0.0476. __________________________________________________________________________ Im Zusammenhang mit unseren Arbeiten zum komplexchemischen Verhalten von Berylliumchlorid und Halogenido-Beryllaten [1] haben wir unlängt über Synthesen und Kristallstrukturen der beiden Kronenether-Komplexe [Be(12-Krone-4)Cl] + [SbCl 4 ] -[2] mit verzerrt tetragonal-pyramidaler Struktur des Kations und über den Molekülkomplex [BeCl 2 (15-Krone-5)] [3] mit verzerrt tetraedrischer Koordination am Berylliumatom berichtet. DFT-Rechnungen ergaben, daß die exocyclische Anordnung des BeCl 2 -Fragments in Übereinstimmung mit dem Experiment die bei weitem stabilste Anordnung darstellt [3]. Bei Versuchen zur Koordination von BeCl 2 an 18-Krone-6 ergab sich nun als einziges isolierbares Produkt der zweikernige Molekülkomplex [(BeCl 2 ) 2 (18-Krone-6)], was nach einer Recherche im Cambridge Crystallographic Data Centre ein Novum darstellt. Dagegen bilden die mit BeCl 2 valenzisoelektronischen Spezies MgCl 2 und {AlCl 2 } + mit 18-Krone-6 jeweils nur die einkernigen Komplexe [(MgCl 2 )(18-Krone-6)] [4] und [(AlCl 2 )(18-Krone-6)] + [EtAlCl 3 ] -[5] mit jeweils verzerrt oktaedrischer Koordination an den Metallatomen. Wir ergänzen unseren Bericht über DFT-Rechnungen an [(BeCl 2 ) 2 (18-Krone-6)] und über die Kristallstrukturanalyse seines Hydrolyseproduktes, das als Tris(µ-Hydroxo)hexaaquatriberylliumtrichlorid mit eingelagerter 18-Krone-6 identifiziert wurde. )chlorid reagiert in Suspensionen von Dichlormethan oder Acetonitril mit 18-Krone-6 unabhängig von den angewandten molaren Verhältnissen der Reaktanten unter Bildung des Molekülkomplexes 1 gemäß Gleichung (1).

3 Kristallstrukturanalysen

 3 Alternativgebots in beiden Schwingungsspektren(Tabelle 1) lassen sich insbesondere bei den wenig charakteristischen Schwingungen der CH 2 -Gruppen beobachten. Wir haben deshalb auf die Auflistung der CH 2 -Valenzschwingungen in Tabelle 1 verzichtet. Die für die Anzahl der berechneten Gerüstschwingungen in den Spektren von 1 je 33 Banden im IR-und im Raman-Effekt werden nicht ganz erreicht. Wir führen dies auf zufällige Entartungen zurück, was auch im Einklang ist mit der sehr engen Streubreite der C-C-und C-O-Bindungslängen (siehe Tabelle 3 in Abschnitt 3.1). Der Vergleich zwischen den skalierten, berechneten (RB3LYP/6-31G*) und den gemessenen Schwingungsfrequenzen zeigt eine gute Übereinstimmung. Das Skalieren der berechneten Frequenzen hat sich generell als notwendig erwiesen, da bei der Berechnung Anharmonizitätseffekte vernachlässigt werden [20]. Zusätzliche Abweichungen zwischen berechneten und gemessenen Werten ergeben sich durch Nachbargruppeneffekte in den Kristallen bzw. in der Nujol-Verreibung, da bei der Berechnung nur ein einzelnes, isoliertes Molekül betrachtet wird. Unabhängig davon bleiben einzelne Zuordnungen in Tabelle 1 wegen des Fehlens von spektroskopischen Vergleichen unsicher. Für zwei experimentell beobachtete, aber in den DFT-Rechnungen nicht realisierte Banden schlagen wir Kombinationsschwingungen von Gitterschwingungen mit entsprechenden Grundschwingungen vor. Für diese treffen die Auswahlregeln für Ober-und Kombinationsschwingungen [10] zu. Tabelle 2 enthält die kristallographischen Daten und Angaben zu den Strukturlösungen von [(BeCl 2 ) 2 (18-Krone-6)] (1) und [{Be 3 (µ-OH) 3 (H 2 O) 6 (18-Krone-6)]Cl 3 ⋅3H 2 O (2⋅3H 2 O). In den Tabellen 3, 4 und 5 sind die Bindungslängen und -winkel sowie die Strukturparameter der Wasserstoffbrückenbindungen zusammengestellt. Die Kristalle wurden auf einem Flächendetektorsystem (IPDS2, Stoe) mit graphitmonochromatisierter MoKα-Strahlung vermessen. Die Strukturen wurden mit Direkten Methoden gelöst (SHELXS-97 [14a]) und mit voller Matrix gegen die F 2 -Daten verfeinert (SHELXL-97 [14b]). Für alle schwereren Atome wurden anisotrope Auslenkungsparameter verwendet. Wegen der guten Kristallqualität von 1 konnten die H-Atome mit isotropen Auslenkungsparametern frei verfeinert werden, bei 2 wurden sie an den Kronenethermolekülen auf berechneten Lagen "reitend" einbezogen. An den OH-Gruppen wurden die O-H-Abstände auf 85.0(5) pm eingeschränkt. Die Aqua-Liganden wurden aus einer Differenzfouriersynthese lokalisiert und als starre Gruppen mit idealisierten Abmessungen (O-H-Bindungslänge 85 pm, Winkel H-O-H 109.5°) verfeinert. Für alle H-Atome wurden isotrope Auslenkungsparameter mit U(H) = 1.2 U eq (O) verwendet. (Die kristallographischen Daten (ohne Strukturfaktoren) wurden als "supplementary publication no. CCDC 779177 (1) and 779178 (2)" beim Cambridge Crystallographic Data Centre hinterlegt. Kopien der Daten können kostenlos bei CCDC, 12 Union Road, Cambridge CB2 1EZ (Fax: (+44)1223-336-033; E-mail:

(2⋅3H 2 O

 2 Abbildung 2 sind die Packungsverhältnisse wiedergegeben. Die Moleküleinheiten von 1 sind wie Münzen entlang [010] gestapelt.

1 ( 2 O ( 2 •

 122 aus den Elementen. Acetonitril (Merck) wurde in der Aldra SORB-Qualität eingesetzt, Dichlormethan (Merck) wurde in einer Säule von Sikapent und Aluminiumoxid nachgereinigt. 18-Krone-6 (1,4,7,10,13,16-Hexaoxacyclooctadecan) war ein Präparat der Firma Fluka (99%ig). Die IR-Spektren wurden mit dem Bruker-Gerät IFS-88 registriert, Nujolverreibungen, Silberchlorid-und Polyethylenscheiben. Für das Raman-Spektrum stand das Gerät Labram HR 800 von Jobin Yvon zur Verfügung; He/Ne-Laseranregung 632.817 nm. [(BeCl 2 ) 2 (18-Krone-6)] (1). Beryllium(II)chlorid (0.15 g, 1.88 mmol) wurde in 5.0 mL Acetonitril suspendiert und mit 18-Krone-6 (0.29 g, 1.09 mmol) versetzt. Der Ansatz wurde 24 h bei 20 °C gerührt, wobei eine homogene weiße Suspension der Verbindung 1 entstand. Nach Filtration und Trocknen im Vakuum erhielten wir 0.42 g mikrokristallines Pulver Ausbeute 95.5 %). Einengen des Filtrats unter vermindertem Druck bis auf 3.0 mL und Ruhigstellen bei 20 °C führte zu gutausgebildeten, farblosen, plättchenförmigen Einkristallen von Verbindung 1, die für die Kristallstrukturanalyse geeignet waren. 3H 2 O). Eine Probe des mikrokristallinen Kristallpulvers der Verbindung 1 wurde drei Tage unter staubfreien Bedingungen auf einem Uhrglas feuchter Luft ausgesetzt. Hierbei entstanden reichlich nadelförmige Einkristalle, die sich durch Auslesen separieren ließen und die für die Kristallstrukturanalyse geeignet waren. Quantenchemische Rechnungen Die diskutierten Strukturen wurden mit B3LYP/6-31G* [18] vollständig optimiert und durch Berechnung der Schwingungsfrequenzen als lokale Minima (NImag: 0) charakterisiert. In früheren Arbeiten zeigte sich, daß B3LYP/6-31G* als Methode zur Berechnung von Schwingungspektren gut eignet ist [19]. Zum Vergleich zwischen dem berechneten und dem experimentellen Schwingungsspektrum wurden die berechneten Frequenzen nach Scott und Radom mit 0.914 skaliert [20]. Die relativen Energien der beiden Isomere von 1 wurden mittels B3LYP/6-311+G** (B3LYP/6-311+G**//B3LYP/6-31G*) und MP2(full)/6-311+G** (MP2(full)/6-311+G**//B3LYP/6-31G*) Energierechnung überprüft, wobei die ZPE-Werte unkorrigiert blieben. Die Gaussian 03 Programsuite kam ausschließlich zum Einsatz [21]. Danksagung Der Dank der Autoren gilt Herrn Prof. Dr. Dr. h. c. mult. Rudi van Eldik und Herrn Prof. Dr.

  kristallisiert monoklin in der Raumgruppe P2 1 /n mit zwei Formeleinheiten pro Elementarzelle. Die gute Kristallqualität ließ eine sehr genaue Strukturbestimmung zu, zudem wurde die Struktur von 1 ebenso wie die von 18-Krone-6 [11] bei 100 K bestimmt, so daß präzise Vergleiche möglich sind. 1 bildet die in Abbildung 1 wiedergegebene zentrosymmetrische Molekülstruktur der Symmetrie C i . In ihr sind die beiden Berylliumatome der BeCl 2 -Gruppen exocyclisch mit jeweils zwei benachbarten Sauerstoffatomen des Kronenethers unter Bildung von BeO 2 C 2 -Fünfringen verknüpft. Wie in der Struktur von [(BeCl 2 )(15-Krone-5)] [3] nehmen auch in 1 die Fünfringe twist-

	Konformation ein, die wir auch in der Struktur des Diisopropylcyclohexyl-1,2-diamin-
	Komplexes (R,R,S

2 ) 2 (18-Krone-6)] (1) 1 N ,S N' )-[(BeCl 2 )(C 12 H 26 N 2 )] [12] beobachtet haben. Aufgrund des sehr kleinen Ionenradius des Be 2+ -Ions von 41 pm für C.N. vier [13] und der daraus folgenden stark polarisierenden Wirkung sind die O-Be-O-Bindungswinkel in 1 mit 92.4(1)° recht groß

  Be-O-und Cl-Be-Cl-Winkeln. Das C i -Isomer hat mit 89.3° und 121.1° minimal größere Winkel als das C 2 -Isomer (88.5° und 120.6°). Einen deutlicheren Unterschied messen wir bei den O-C-C-O-Diederwinkeln in den fünfgliedrigen Chelatringen. Hier zeigt sich wohl am deutlichsten, daß sich das C 2 -System stärker verdrehen muß (42.0°), um das zweite BeCl 2 -Molekül zu chelatisieren, als das stabilere Molekül der Symmetrie C i (36.3°).

	Kronenethermoleküle behalten ihre Zentrosymmetrie wie in der Struktur von 18-Krone-6 [11], wobei auch die gemittelten Strukturparameter nur geringe Abweichungen voneinander aufweisen: 2⋅3H 2 O [diese Arbeit] 18-Krone-6 [11] Die supramolekulare Struktur von 2⋅3H 2 O wird ergänzt durch ein komplexes Netzwerk von O-H … O-und O-H … Cl-Wasserstoffbrückenbindungen, an der alle funktionellen Gruppen einschließlich der eingelagerten H 2 O-Moleküle beteiligt sind (siehe Tabelle 5). 4 DFT-Berechnung [(BeCl 2 ) 2 (18-Krone-6)] (1) Da sowohl im Schwingungsspektrum als auch nach der Kristallstrukturanalyse nur ein zentrosymmetrisches Strukturisomer der Symmetrie C C i C 2 RB3LYP/6-31G*// RB3LYP/6-31G* + ZPE( RB3LYP/6-31G*) 0.0 0.8 RB3LYP/6-311+G**// RB3LYP/6-31G* + ZPE( RB3LYP/6-31G*) 0.0 1.5 RMP2(full)/6-31G*// RB3LYP/6-31G* + ZPE( RB3LYP/6-31G*) 0.0 1.3 Unterstützt wird dieser Befund durch einen Vergleich der beiden berechneten (RB3LYP/6-31G*), von Nachbargruppeneffekten unbeeinflussten Strukturen (Abbildung 5). Die Be-O-ZAAC Bindungslängen in beiden Isomeren sind nahezu gleich, aber mit 175 pm bzw. 173 pm für C Page 13 of 27 in den O-
	C-O	142.5 pm	142.3 pm
	C-C	149.4 pm	151.2 pm
	C-O-C	111.7°	112.8°
		Wiley-VCH

). Wie Abbildung 4 zeigt, sind sie entsprechend einer hexagonalen Stabpackung angeordnet. Die Struktur des Tris(µ-Hydroxo)hexaaquatriberyllium-Trikations unterscheidet sich nur wenig von der gleichen Struktureinheit in (Ph 4 P) 2 [Be 3 (µ-OH) 3 (H 2 O) 6 ]Cl 5 [9], in der die Be-OH-Abstände im Mittel 159.5 pm betragen gegenüber 159.0 pm in 2, und Be-OH 2 im Mittel 165.0 gegenüber 164.8 pm in 2. Da auch die Konformation des Be 3 (µ-OH) 3 -Sechsringes in beiden Verbindungen recht ähnlich ist, haben wir für 2⋅3H 2 O keine DFT-Rechnungen ausgeführt. Auch die i gefunden wurde, stellten wir uns die Frage, warum nicht auch das zweite, C 2 -symmetrische Isomer, bei dem die beiden BeCl 2 -Einheiten an benachbarte Sauerstoffdonoren gebunden sind, gebildet wird. Die Berechnung der beiden Isomere von [(BeCl 2 ) 2 (18-Krone-6)] (1) zeigt einheitlich eine höhere Stabilität des C i symmetrischen Isomers gegenüber dem C 2 symmetrischen (vgl. Tabelle 6). Dies führen wir auf destabilisierende sterische Einflüsse der BeCl 2 koordinierenden Chelatsysteme im C 2 -Fall zurück. Tabelle 6. Relative Energien / kcal•mol -1 der beiden Isomere von [(BeCl 2 ) 2 (18-Krone-6)] (1) i und 176 pm bzw. 174 pm für C 2 etwas verlängert im instabileren Isomer. Im Fall der ungestört vom Kronenether wegzeigenden Be-Cl Bindungslängen haben beide Isomere mit 196 pm und 195 pm nahezu dieselben Abstände. Ebenso geringe Abweichungen finden sich

  Kristallographische Daten von [(BeCl 2 ) 2 (18-Krone-6)] (1) und [{Be 3 (µ-OH) 3 (H 2 O) 6 }(18-Krone-6)]Cl 3 ⋅3H 2 O (2⋅3H 2 O) Summenformel C 12 H 24 Be 2 Cl 4 O 6 C 12 H 45 Be 3 Cl 3 O 18

	Page 21 of 27				ZAAC ZAAC		Page 22 of 27
	Tabelle 1. Schwingungsspektrum von [(BeCl 2 ) 2 (18-Krone-6)] im Vergleich mit dem von 18-Krone-6 (ohne CH-Valenzschwingungen). Berechnete Daten kursiv in Klammern. [(BeCl 2 ) 2 (18-Krone-6)] 18-Krone-6 Zuordnungen Raman/cm -1 IR/cm -1 Raman/cm -1 IR/cm -1 Exp. Ber. Exp. 1491 w 1491 m 1485 m (1487) 1465 vw 1455 m (1451) 1457 m (1451) 1453 w 1444 m 1426 vw (1419) 934 w (931) 932 st (925) 936 vw 920 w (902) 918 w 303 vst (301) τBeO 2 , A g α/° 90 80.233(8) (908) 315 w (339) 307 w c/pm 889.1(1) 1275.72(13) ωBeO 2 , A u 1456 st 944 st 320 m b/pm 1373.9(1) 1236.12(11) δCOC (1468) 986 vst 990 st 347 m (373) a/pm 747.5(1) 1046.04(9) δBeO 2 , A g 1476 w νC-O br Kristallabmessungen/mm 0.16 × 0.16 × 0.11 10 -6 e/pm 3 0.21 × 0.08 × 0.03 1488 w 1018 vw 995 w (1011) τCH 2 , 355 vw, (374) 350 w 352 w δ Gerüst 424.13 610.86 max. Restelektronendichte/ 0.192 0.323 Formelgewicht/g/mol -1 (1016) 405 st wR 2 (alle Daten) 0.0374 0.0954 127, A g + 260 A u Ber. 1113 w (1109), (1115) 1110 vw 1107 vst 1085 w (1084) 1089 m 1068 m (1083) 1063 vw 1061 vw 1047 m (1055) 1028 vw (1040) 414 st δ Gerüst Strahlung Mo-K α R 1 0.0233 0.0476 Mo-K α 1042 m 429 st 111, A g + 303, A g Instrument IPDS II (Stoe) IPDS II (Stoe) H-Atome frei verfeinert reitend 1045 vst 450 w Verfeinerung gegen F 2 SHELXL-97 [14b] 1058 w δ Gerüst 531 m (543) ν as BeCl 2 , A u 522 m δ Gerüst 506 m (512) 505 m (472) ν s BeCl 2 , A g , A u (469) 463 w 2⋅3H 2 O Reflexe mit F o >4σ(F o ) 1308 3616 Parameter 157 361 (SHELXS-97 [14a]) Tabelle 5. H-Brückenbindungen in 2•3H 2 O [pm und °]. Tabelle 2. 1 Strukturlösung direkte Methoden D-H … A d(D-H) d(H … A) d(D … A) <(DHA)
	276 w β/° γ/°	(280)	279 w 94.84 867 m 90	(296) (896)	1411 vw 1386 vw 890 vst 863 st 269 vst	1411 w 887 w 66.439(7) 859 st 80.053(7)	ρBeO 2 , A g , A u δCH 2 δ Gerüst
	1300 w 1287 w 857 vst, 838 st Zellvolumen/pm 3 (1274) 1298 m (1278) (1271) (850) 260 m (277) 920.1(2)⋅10 6 229 w (223) Z 2 d rönt /g/cm -3 1.531	1373 w 1295 m 1278 m 833 vw 187 vw 821 w 218 m	1376 st 1297 st 1480.0(2)⋅10 6 δBeCl 2 , A u ρCH 2 δBeCl 2 , A g 2 828 m δ Gerüst 1.371
	Kristallsystem		1261 w 802 w 180 sh monoklin (1265) (807) (181)	1258 vst	1260 m triklin	ωBeCl 2 , A u
	1244 m Schwingungen unter Beteiligung der Berylliumatome. Rasse A g jeweils Gleichtaktschwin-(1247), 166 vst 123, A g + Gitter-Raumgruppe P2 1 /n P1
	(1248) gungen (in-phase), Rasse A u jeweils Gegentaktschwingungen (out-of-phase) schwingung, A u Absorptionskorrektur numerisch semiempirisch
	Tim Clark für die gewährte Unterstützung und dem Regionalen Rechenzentrum Erlangen (RRZE) für die großzügige Bemessung von Rechenzeit. 1239 w 1232 w (1226) 795 w (806) 161 st (164) τBeCl 2 , A g µ/cm -1 6.67 3.78 ν as BeO 2 , A g 1235 w 681 st (710) 141 w (147) 145 vw δ Gerüst Meßtemperatur/K 100(2) 100(2) ν as BeO 2 , A u 1215 vw 652 st (631) ν s BeO 2 , A u 127 m (130) ρBeCl 2 , A g 2θ max /° 51.76 52.00
	1167 vw 615 w hkl-Werte	(1153)	614 w 123 st -9 ≤ h ≤ 9, -16 ≤ k ≤ 16, (122) 120 m	ρBeCl 2 , A u -12 ≤ h ≤ 12, -15 ≤ k ≤ 15,
	1146 vw 111 vst 92 w gemessene Reflexe (1138) 1144 m (1139) 570 m (586) (112) (93) -11 ≤ l ≤ 11 11735	1157 m 1136 vst 578 w	δCCO Gitter--15 ≤ l ≤ 15 1132 vst 569 m schwingungen ν as BeCl 2 , A u , 11465
	1124 vw 561 st unabhängige Reflexe (1121) (585)	1786			5756	ωCH 2 , ν s BeO 2 , A g
	R int		0.0553		0.0762	νC-C
				Wiley-VCH Wiley-VCH


Wolfgang Lutz
email: lutz@btu-lc.fta-berlin.de

Btu Cottbus

Luftchemie Enke

D Enke

W.-D Einicke

D Täschner

E Kurzhals

Mesopores in USY Zeolites

Keywords: zeolite, dealumination, faujasite, mesopores zeolite, dealumination, faujasite, mesopores

Zeolites of type NaY synthesized by use of seed-solution and zeolite X-seeds to initialise the crystallization were compared. A different homogeneity of the internal framework structure related to the Si/Al ratio was expected. Thus, the formation of closed bulk mesopores should be influenced during treatment of NH 4 NaY modification for 7 hours at 450°C and 600°C in the water steam of 1 bar. Occurrence of different mesopores was actually observed in obtained ultra-stable USY zeolites using Nitrogen adsorption. Whereas USY prepared by use of seed-solution contains only open mesopores at the crystal surface, the X-seed synthesized material contains open and closed mesopores at the surface and in the nuclei of samples, respectively.

Introduction

Zeolites of NaY type with framework Si/Al ratios between 2.2 and 2.7 are suitable to be dealuminated [1]. Ion-exchanged NH 4 NaY modification is transformed thereby into catalytic active USY (ultra-stable Y) samples [2]. The process proceeds in a steam treatment at elevated temperature [START_REF] Mcdaniel | Molecular Sieves[END_REF].

Recently, the formation of two types of mesopores was reported as a result of the samples treatment for 7 hours in the steam of 1 bar water pressure at 450°C and 600°C [4]. Closed bulk mesopores were found inside the traditionally synthesized NaY X-seeds crystallites surrounded by the microporous zeolite framework. Open mesopores were located near the crystallite surface. They occurred due to partial decomposition of the Aluminium-rich crystallite nuclei and corrosion of the Silicon-rich crystallites surface, respectively [5].

The non-homogeneous Si/Al distribution is typical for most NaY X-seeds zeolites [6] prepared by use of silica gel, solution of sodium aluminate and, frequently, seeds of zeolite X [7,8].

Zeolites of X and Y types are modifications of one and the same faujasite crystal type (FAU).

They distinguish only in their Silicon to Aluminium ratio. While for X a Si/Al ratio of 1 to 1.2 is typical [START_REF] Breck | Zeolite Molecular Sieves[END_REF], Y is characterized by Si/Al values > 2.2 [1].

Crystallization of the FAU framework starts according to the traditional synthesis path-way in general from aluminosilicate gels with Si/Al distribution close to that of zeolite X composition [6]. Because of excessive consumption of aluminate ions at the beginning of the synthesis, the batch solution becomes more and more rich in silicate ions. This is the reason why crystal formation starts with an Aluminium-rich nuclei but finishes with a Silicon-rich surface.

It was found earlier that FAU zeolites, being rich in Aluminium or Silicon, show hydrothermal instability. In steam they are decomposed according to an "acid" or "alkaline" mechanisms [1]. This effect is responsible for decomposition and corrosion of parts of the Page 2 of 11 Wiley-VCH ZAAC NaY X-seeds framework with non-homogeneous Si/Al distribution, too. Amorphous aluminosilicate and silica gel as siliceous extra-framework admixtures occur thereby [START_REF] Lutz | [END_REF].

A modified synthesis pathway for zeolite NaY seed-solution should hinder the formation of such strong gradient. This strategy uses so-called seed-solution to initialise the crystal growth of Ytype composition, already at the beginning of synthesis process [11].

Seed-solution consists of sodium silicate molecules of oligomeric chain length (5-15 Silicon atoms) in aqueous alkaline solution with some aluminate ions inside. The slightly opaque solution should favour the formation of sodalite cages as main building units of the FAU structure with a higher portion of Silicon atoms, being also in the nuclei of crystallites.

With respect to hydrothermal stability, the nuclei of such modified NaY seed-solution should be more stable than that of NaY X-seed products. Therefore, the formation of bulk mesopores should be hindered or at least minimized on this way.

Results and Discussion

According to unit cell composition of Na 53 [(AlO 2 ) 53 (SiO 2 ) 139 ] and Na 52 [(AlO 2 ) 52 (SiO 2 ) 140 ], respectively, the NaY seed-solution and NaY X-seeds samples are chemically pseudo identical.

Consequently, the Si/Al ratios calculated by use of the IR double ring vibration w DR and the framework constant a 0 are with values of 2.6-2.7 identical. After steaming, the values preserve as very close. Dealumination changes Si/Al ratios from 3.0 -3.3 (450°C) to 3.9 -4.2 (600°C) (Table 1).

Micropore volume V micro and micropore surface A micro of NaY and USY samples of both series differ only to a small extent as shown in Table 2.

The greater difference of the total volumes V total between both series determined from nitrogen isotherms at p/p 0 = 0.9995 results from a higher free space (macropores) between crystallites of the polycrystalline NaY seed-solution particles [4]. This different sample behaviour Page 3 of 11 Wiley-VCH ZAAC can be identified also by the shape of isotherms in Figure 1 and 2 (A). NaY seed-solution shows significant condensation of nitrogen inside the macropores at relative pressure higher than p/p 0 = 0.9. Similar tendency is observed for steamed USY samples (B, C), too.

The mesopore area A meso differs in opposite way. Values of NaY seed-solution are smaller for initial as well as steamed samples than those of NaY X-seeds zeolites. The difference characterizes absence of internal mesopores in NaY seed-solution . The corresponding nitrogen isotherms show no hysteresis loop for the 450°C steamed sample (Figure 1 B) and only a weak one for 600°C (C). Letter starts at p/p 0 = 0.7 thus characterizing the emptying of the mesopores of the outer crystallite surface. Contrary to this observation, 600°C sample of NaY X-seed (Figure 2 C) shows a second step beginning at p/p 0 = 0.45 resulting from emptying of the internal bulk mesopores. Thus, the different run of isotherms characterizes different mesopore systems in USY zeolites in dependence of use of seed-solution or type X-seeds for initialisation of the crystallization process.

Experimental Section

Zeolite of type NaY seed-solution was synthesized according to a recipe of the former Zeosorb modification was washed with water and dried at 120°C for 1 hour. The ion exchange was limited to 79%. Under analogous conditions zeolite NaY X-seeds was ion-exchanged [4].

The hydrothermal treatment of samples of both series was performed in steam of 1bar water pressure at 450°C or 600°C for 7 hours. The heating rate of the process was equal to 10 centigrade per minute. The samples were contacted with steam after reaching the chosen temperature.

The obtained USY samples were characterized by X-ray diffraction, IR spectroscopy and nitrogen adsorption. XRD data were recorded on a Philips PW 1800 powder diffractometer equipped with a graphite monochromator and Cu Kα radiation at 40 kV and 40 mA.

Measurements were performed in the 2θ range between 5 ° and 85 ° with a step of 0.03 ° and a coupling time of 1 sec count per step.

IR absorption spectra were taken on a Shimadzu FTIR 8400S spectrometer with a resolution of ± 1 cm -1 by use of 30 scans. For analysis, 0.5 mg of the sample was pressed with 400 mg KBr into a pellet while spectra were registered in the IR range from 400 to 4000 cm -1 .

Nitrogen sorption measurements at -196°C were performed by use of a ASAP 2010 apparatus by Micromeretics. All samples were degassed at 350°C before measurement for at least 24 hours at 10 -5 mbar. Adsorption and desorption isotherms were measured over a range of relative pressures (p/p 0 ) from 0 to 1.0. The surface area of the micropores A micro , the micropore volume V micro and the surface area of the mesopores A meso were determined according the t-plot method [START_REF] Lippens | [END_REF]. The total pore volume V total was estimated from the amount of gas adsorbed at the relative pressure p/p 0 = 0.996 assuming that pores were filled Page 5 of 11 Wiley-VCH ZAAC subsequently with condensed adsorptive in the normal liquid state. Finally, the mesopore volume V meso was calculated according to V meso = V total -V micro .

(1)

Si/Al ratios of USY were determined by the IR spectroscopic double ring vibration w DR and the lattice constant a 0 [14] according to Equations ( 2) and ( 3)

x =

  GmbH (Bitterfeld) by homogenization of 9 mole SiO 2 in a solution of 1 mole Al 2 O 3 , 3.5 mole Na 2 O and 120 mole H 2 O at ambient temperature. The synthesis was carried out without aging of the aluminosilicate gel under stirring at 95°C for 36 hours. 25 g seed-solution was added to 1900 g of the batch. The composition of the seed-solution amounted to 15 mole SiO 2 and 1 mole Al 2 O 3 in an aqueous solution of 13 mole Na 2 O in 215 mole water. For dealumination, zeolite NaY seed-solution was transferred into the ammonium modification by a three-fold ion-exchange in 0.1 M aqueous solution of NH 4 NO 3 at room temperature for 1 hour in each step and by use of a liquid/solid mass ratio of 100. The obtained NH 4 NaY

  3.857 -0.00619 w DR (cm -1 ) (2) (with Si/Al = (1-x)/x and x = Al molar fraction by use of the sensitive double-ring vibration) respectively x = 5.348a 0 -12.898 (3) (with Si/Al = (1-x)/x and x = Al molar fraction by use of the cell parameter a 0 ).

Figure 1 NitrogenFigure 2

 12 Figure 1

Table 1

 1 Si/Al ratio of initial NaY seed-solution and USY steamed at 450°C respectively 600°C in comparison with NaY X-seeds and USY samples of Reference[4]

					Page 8 of 11
	sample	IR	Si/Al	XRD	Si/Al
		w DR , cm -1	acc. to Eq. (2)	a 0 , nm	acc. to Eq. (3)
			seed-solution
	NaY seed-solution	579	2.7	2.462	2.7
	USY, 450°C	584	3.1	2.456	3.2
	USY, 600°C	592	4.2	2.450	3.9
			X-seeds
	NaY X-seeds	580	2.7	2.465	2.6
	USY, 450°C	586	3.3	2.458	3.0
	USY, 600°C	592	4.2	2.451	3.9

Table 2

 2 Pore structure of initial NaY seed-solution and USY steamed at 450°C respectively 600°C in comparison with NaY X-seeds and USY samples of Reference[4]

	Page 9 of 11
	sample	V total , cm 3 /g	V micro , cm 3 /g	A micro , m 2 /g	A meso , m 2 /g
			seed-solution
	NaY seed-solution	0.44	0.35	863	19
	USY, 450°C	0.41	0.30	742	30
	USY, 600°C	0.40	0.27	682	34
			X-seeds
	NaY X-seeds	0.35	0.36	815	24
	USY, 450°C	0.35	0.30	735	34
	USY, 600°C	0.33	0.25	630	40