Re-defining the musical: adapting Cabaret for the screen

Anouk Bottero

When Stephen Harnick, the lyricist of many successful musicals such as Fiddler on the Roof (1964), was first presented with the idea of adapting Christopher Isherwood's Berlin Stories (1945), he quickly dismissed it: "It can't be done. Maybe you could make a play out of it, but not a musical". 1 Harnick did not seem to have heard of John Van Druten's 1951 stage adaptation I Am a Camera, but "[i]t seemed as if nobody seriously believed that Christopher Isherwood's semiautobiographical Berlin stories or John Van Druten's stage adaptation of the 'Sally Bowles' story could be made into a Broadway musical". 2 To see that what was to become one of America's best-known musicals was initially regarded as unfit for the Broadway stage and "inadaptable" to the musical genre may now seem quite striking. More precisely, the multiplicity of sources presiding over the conception of Cabaret points to the musical's adaptability and its malleable dimension. The critical and popular acclaim garnered by stage director and producer Harold "Hal" Prince's original staging of Cabaret (libretto by Joe Masteroff, music and lyrics by John Kander and Fred Ebb) in 1966, 3 as well as director-choreographer Robert Louis "Bob" Fosse's 1972 film adaptation (starring Liza Minnelli and Joel Grey),4 also questions the implicit criticism that the subject did not fit in the happy-go-lucky world of musical theatre and film, or did not answer the genre's commercial and mainstream obligations. Indeed, a musical taking place in a seedy and decadent 1930s Berlin cabaret, against the backdrop of the Nazis' gradual ascent to power, might not have seemed a very likely subject for Broadway and Hollywood, even at the beginning of the 1960s. In that perspective, Cabaret remains a pivotal musical, insofar as both Prince's and Fosse's versions challenged the conception of what could be considered good material for a musical-and what a musical was supposed to be and look like.

This initial paradox seems to concur with a moment of crisis that was faced by the genre of the musical, both in the theatre and the film industries, during the 1960s. The second half of the 1960s marked the end of the "Golden Age" of musicals, a period usually comprised by 1 Quoted in Keith Garebian, The Making of Cabaret, Oxford, OUP, 2011, p.15. 2 Ibid., p.3. 3 The original production of Cabaret ran for 1,166 performances when it first opened on Broadway, and won 8 awards out of 11 nominations at the 1967 Tony Awards, among which Best Musical, and Best Direction in a Musical. most researchers between 1943 and 1964. 5 The reasons for this decline in popularity were mostly due to the economic fallout faced by Broadway and the musical film industry-a crisis which challenged the musical's establishment as a paragon of popular culture 6 -but also to the revolutionary socio-cultural changes that shaped most of the 1960s, and which made it even more difficult for musicals to "sustain [their] habitual veneer of happiness." 7 In that context, Hal Prince's original production of Cabaret seemed to bring to the stage musical the breath of fresh air it needed, by making it darker, more political, and more cynical, and moving away from the musical's "integrated form"-in which all elements of the musical concur to the advancement of the plot 8 -towards a new, director-driven "concept musical". 9 If the conception of Cabaret on stage was marked by a conscious move to transform the musical as a genre, its film adaptation gave way to the possibility for a musical to transform itself, especially if transferred onto the screen. For Geoffrey Block, Fosse's Cabaret signs "the end of an era that generally features more faithful adaptations, an era significantly framed, as with the Golden Age musical, by the films of Oklahoma! (1955) and Fiddler on the Roof (1971)." 10 After Fosse's Cabaret, there were simply two very distinct Cabarets. Such distinctiveness of the film adaptation compared to its stage counterpart is also linked to the emerging prominence of the director's role in the conception of musicals. Hal Prince's production demonstrated the paramount importance a director of musicals could have on a stage production. 11 Fosse, by moving away from constraints of fidelity towards the original point of reference (the stage production), also followed Prince's redefinition of the role of the director 12 and more specifically, of the director-choreographer-despite a lack of classical ballet training and a relative ignorance of filmic vocabulary. 5 1943 marks the year of the first "fully" integrated musical, Rodgers & Hammerstein's Oklahoma!, whereas 1964 was the year of high-rated performances such as Funny Girl, Hello, Dolly! or Fiddler on the Roof.

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To learn more about the economic aspect of Broadway's fading popularity, see Modern Drama, vol. 47, no. 2, 2004, p.315. 8 See Geoffrey Block, "Integration", in Raymond Knapp, Mitchell Morris and Stacy Wolf (dir.), The Oxford Handbook of the American Musical, New York, Oxford University Press, 2011, pp.97-110. 9 The general definition of the "concept musical" is that a "concept," i.e. the vision and/or the subject, governs and drives all the elements of the production, rather than the narrative. Ibid., pp.104-105. 10 Ibid., p.105. We can notice that the film musical's transformation follows the transformation of the stage musical pretty closely. 11 Usually, the paternity of musicals tends to be attributed to composers ("a Rodgers and Hammerstein musical," "a Stephen Sondheim musical"), a habit which does not always reflect the paramount influence of the choreographer, the lyricist or the director. See Jim Lovensheimer, "Texts and Authors", in Raymond Knapp, Mitchell Morris and Stacy Wolf (dir.), The Oxford Handbook of the American Musical,op. cit., About the directors' vision's role in transforming Cabaret: "[…] the film was directed by Bob Fosse, not Harold Prince, and was accordingly informed by a different sensibility." In Keith Garebian, The Making of Cabaret, op. cit., p.133. In many ways, Cabaret thus embodies a correlation between questions of adaptation, the subsequent transformations such translation from one medium (the stage) to another (the screen) entails, and a moment of redefinition of the genre. If most commentators shed light upon Cabaret's disruptive dimension and how it set a precedent for the genre of the musical, I will try to shift this perspective onto the adaptations of Cabaret, from stage to screen and back again, so as to show how they too might have enriched the genre's mutations throughout the decades. In order to do this, I will take Fosse's Cabaret as the focal point of my analysis. This choice is not out of contempt for Hal Prince's highly innovative original production, but because Fosse's film remains the most democratic access to this musical. To study the film's departure from the original production is a way of analyzing the transfers that have been made from Broadway to Hollywood, and of understanding how Fosse himself managed to create a specifically cinematographic Cabaret. This will also enable me to consider the extent to which the film has, in an amusing reversal, become a point of reference for audiences of subsequent stage revivals. Therefore, this article will follow the diachronic evolution of Cabaret, from its conception to its cinematographic reinvention, and to its reversed impact on stage performances of the musical.

Adapting Cabaret: leaving the theatre behind?

For audiences who saw Fosse's 1972 film while having Prince's 1966 production in mind, Cabaret might have seemed like a completely different musical. The subplot was considerably altered: the amusing storyline of the older couple composed of Fraulein Schneider and Herr Schultz was replaced by the dramatic infatuation of gold-digger (and Jew in disguise) Fritz Wendel with wealthy Jewish heiress Natalia Landauer. Quite an important number of songs were replaced by newly-created ones: "Mein Herr" replaced "Don't Tell Mama" as Sally Bowles's introductory song, whereas the song "Maybe This Time" has "no direct counterpart in the stage version."13 Only Joel Grey reprised his role as the Emcee; the controversial British Sally played by Jill Haworth14 was replaced by a stunning and buoyant American Sally Bowles portrayed by Liza Minnelli. Cliff, an aspiring American writer, became a British Cambridge graduate named Brian. So many changes might seem vertiginous and quite daring as they touch upon the very storyline and draw a radically different vision of the characters. In classic screen adaptations of stage musicals, there was a commercial logic at work that would prompt the creation of new and flashy musical numbers to compensate for the film's lack of live performance. 15 Contrary to this logic, Fosse did not try to compensate and removed a lot of songs-every song that would not take place within the Kit Kat Klub (the notable exception being "Tomorrow Belongs to Me"). Somehow, he had understood the necessity to make musical film a genre that responded to the medium's naturalistic and realistic dimension, without forgetting the theatrical roots of the genre of the musical, as Garebian puts it: "Fosse made realism the rule of his film. No song or dance was ever an affront to realism." 16 Indeed, filmed adaptations of musicals of the Golden Age tended to oscillate between "two poles,"17 which went from a filmed version of a theatrical production to a version without any theatrical apparatus. By keeping musical numbers within a diegetic theatrical space, Fosse tried to position Cabaret outside of these two poles: after this film, all numbers taking place in naturalistic settings, in an apparently natural way, would seem incongruous. As Fosse himself said in an interview with Fabienne Pascaud for French TV and cinema magazine Télérama, "On ne peut plus croire aux héroïnes qui chantent en faisant la vaisselle, ou tournoyent en faisant leurs courses. C'est pour cela que Cabaret […] se [situe] dans le milieu du music-hall."18 And indeed, when Sally Bowles and the Emcee sing, it is because it is their job. And whenever people burst into song outside of a theatrical space, it does not go unnoticed, as in "Tomorrow Belongs to Me": "As the band dies down, a young man who could be the poster boy for Aryan good looks begins to sing. Again, Cabaret is not a musical in which people break into song unremarked, so the crowd takes notice." 19 Performances therefore hold a signifying, metaphorical, ironic value: theatricality is being pointed out, in a Brechtian gesture of alienation (Verfremdungseffekt), but the interpretative weight is slightly displaced compared to the stage version. Indeed, in the stage version, Hal Prince insisted on the play's political content by directly addressing the audience watching the musical. His stage designer, Boris Aronson, created a tilted mirror which was held over the audience in order to reflect it. This breach of the fourth wall, highly reminiscent of Brechtian techniques, was a way of pointing out the illusion-making process, but also of urging the audience to compare the political situation depicted in Cabaret to the United States' own political turmoil. 20 This rather blunt move could not be equally direct in the film, because of the diegetic audience present during the cabaret numbers, and because of the very frontier of the screen and the camera lens. As Garebian notes, the atmosphere of cabarets was particularly fertile for the development of Brecht's alienation effect, precisely because of the immediacy and intimacy between performers and audience. 21 Therefore, "a sense of theatre" 22 needed to be maintained within the film, especially the metaphor encapsulated by the tilted mirror (most visible in the first and last numbers, "Willkommen" and "Auf Wiedersen" sung by the Emcee), in order to obtain the same effect of alienation that the stage production provided.

Focusing on the musical's alienation effect proves important when considering questions of adaptation, because this distantiation mostly played on subtle references to the original production (Prince's 1966 staging). In the film, the first notes of the opening number "Willkommen" accompany a close-up on the Emcee's reflection in a distorted mirror. As the camera rolls back, this distorted mirror reflects the Emcee's back and the audience facing him. As he struts out on stage, the mirror is quickly lifted up, in a clear reference to Aronson's ingenious setup. During this number, there are also several shots of the audience: immobile, these Grösz-like figures also echo Prince and Aronson's staging, as well as Patricia Zipprodt's costumes, which were directly inspired by German expressionism. 23 These spectators are uncanny and strange, but their brief appearance manages to establish a continuum between the diegetic audience and the heterodiegetic one. These painting-like shots interrupt the dynamic of the film, and entice the film's spectators to identify with their onscreen counterparts. There's a definite blurring of audiences in order for this "sense of theatre" to pervade the film. The very presence of Joel Grey as the actor who already played the Emcee on stage (and whom spectators might recognize) also participates to the construction of this sense of theatre. His presence functions as a whimsical reference to Prince's staging, which sets the audience back in the atmosphere of the original production, and somehow "contributes to the blurring of distinction between the three audiences: Broadway, diegetic, and film." 24 The many transformations at the roots of Cabaret's screen reinvention all point to a conscious move to re-create "a sense of theater" on the screen that could bear as much signifying weight as its real stage counterpart. Thus, Brechtian cross-media references to Prince's original stage production contributed to the recreation of the cabaret's atmosphere on screen. But this "sense of theatre" was also informed by stark filmic and cinematographic aesthetics at work in Fosse's redefinition of Cabaret.

Fosse's camera obscura

While theatre is a structuring element of Fosse's adaptation, Cabaret was not meant to resemble either the original stage production, or traditional film adaptations. Through very 21 "Cabaret also helped Brecht formulate his theater practice and theory of Verfremdungseffekt (alienation effect). The small cabaret stage and smoky, sexy atmosphere produced an intimacy and immediacy for performers and audience." Ibid., p.52. 22 "[…] every time we return to the girls and their leering master […] we return, as it were, to a sense of theater." Roger Greenspun, "Movie Review-Cabaret", The New York Times, February 14 th , 1972. 23 Keith Garebian, The Making of Cabaret,op. cit., Randy Clark, "Bending the Genre", art. cit., p.57. specific means such as montage and choreography, Cabaret emphasized the transformations of the film musical genre. Not only did it become darker, but Fosse's own cinematographic aesthetics also transformed the genre's structuring concepts, and added an extra layer of ambiguity to Prince's original stage production.

Choreography proves an interesting point of entry within Fosse's cinematographic vision, as it exemplifies the disruptive dimension of his work as a director-choreographer. Throughout Cabaret, Fosse distorts the musical film's traditional use of choreography. The number "Mein Herr" is very interesting insofar as it is at odds with the classic filming of a number, and shows that Fosse's own choreographic aesthetics presented cinematic qualities. Instead of insisting on the virtuosity of the performer among the ensemble through a fulllength shot, Fosse's camera is very mobile and focuses on details and odd angles of the chorus girls' bodies. Shots of crotches, armpits and knees frame Liza Minnelli's performance. The eye of the spectator is directed to these oddities and small details, which are at the basis of Fosse's choreographic style. 25 This very close attention to detail, especially vulgar and prosaic ones, is already far from the virtuosic and dreamy quality of traditional dance numbers. As Roxane Hamery points out, there is no lyricism of any sort in Fosse's choreography, just a concentration on the gesture. 26 In that perspective, Fosse tries to move away from the glitz and glamour of traditional musical numbers, and this is especially fitting with film since the camera allows for zoom-ins on details which direct the audience's gaze towards the most prosaic dimension of a number.

In keeping with their dreamlike and virtuosic tradition, Golden Age film musicals would normally use dance and choreography, like songs, to draw parallels between the male and female protagonists to create privileged moments of interlude where those characters can "[express] desire without having to take full responsibility for them 27 ." In "Mein Herr", Sally is alone. There is no parallel dancing on Brian's part-he will actually never perform throughout the entire film. Such imbalance shows that the pairing of lovers in parallel scenes, defined by Rick Altman as a constitutive element of the film musical's "overall duality," is no longer viable in Cabaret. 28 Fosse's stance highly contrasts with that of a Robbins in Fiddler on the Roof, which was released just one year before Cabaret, and in which dance still allows Charity (1966 and 1969). In Cabaret, instead of giving the couple a fictional refuge in which they can express their mutual affection, dance merely enables Sally (and only her) not to take responsibility for her inconsistencies, as she playfully sings about her sexual prowess and multiple affairs. The traditional union of the male and female leads is never fulfilled through dance in Cabaret. Much to the contrary, dancing either creates odd and uncanny pairings (such as the Emcee and Sally in "Money, Money"), or upsets the balance of the traditional couple. When Maximilian invites Sally and Brian to his country house, the three of them drunkenly engage into a waltz of sorts during one evening. This dance foreshadows (and somehow leads to) the triangular relationship, which will eventually tear apart Sally and Brian's couple. To some extent, the impossibility for Brian and Sally to exist as a couple is demonstrated through the choreography of music-and-dance numbers. I can go even further and say that the traditional roles given to musical and non-musical sequences seem to be reversed in the film. The union between Natalia and Fritz, which is a very traditional stance on the genre's compulsory secondary love story, belongs to the non-musical realm, and is completed without the help of dance. On the other hand, Sally dances and sings, but Brian and her are not able to fulfil the required pairing of the male and female leads, despite her capacity to perform. Fosse's limitation of choreography and dance to their realistic boundaries endows the film with a darker, more cynical and decidedly different vision of the musical's myths of duality and love. Montage, as a specifically cinematographic element, also plays an important role in the darkening and more ambiguous dimension of Fosse's Cabaret: "[s]ince everything has to do with everything else and the Cabaret is always commenting on the life outside it, the film sometimes looks like an essay in significant crosscutting, or associative montage." 29 Crosscutting is probably the most powerful and visible metaphorical device of the whole film, as it maintains a continuum of interpretation between reality outside of the Kit Kat Klub and the cabaret. Nearly all numbers taking place in the Kit Kat Klub are interspersed with shots of other scenes happening outside of the Cabaret. As early as "Willkommen", the Emcee's opening number is crosscut with shots of Brian arriving in Berlin, "[establishing] the cabaret as a symbol of the metropolis itself." 30 In the original staging, Prince tried to establish such parallel by dividing the stage into two parts-one representing the real world, and the other one (called the "limbo"), the mind. 31 But in Fosse's Cabaret, montage allows for a form of pervasiveness which blurs the metaphorical lines between reality (Berlin) and the realm of the Kit Kat Klub. This is especially visible in "Tiller Girls," in which the chorus girls and the Emcee perform a can-can number. As the number nears the end and the Emcee engages in more bawdy gestures, the camera cuts to another scene where Nazis manage to penetrate the Landauer property, yelling "Juden! Juden!" 32 under Natalia's window. Audience and performers are still raving in another cut to the cabaret, and yet another shot shows Natalia opening her front door, seeing the yellow graffiti spelling "Juden" and the corpse of her dog on the threshold. As she is about to scream, the camera cuts back to the Kit Kat Klub, where the can-can theme is replaced by military music: the chorus girls and the Emcee suddenly turn around their cloche hats, and the high kicks of the Tiller Girls transform into Nazi goose-steps in a very menacing fashion. Suddenly, the scene is no longer funny for the heterodiegetic audience, despite the chilling laughter of the diegetic spectators. We feel confused about the number's message: is the cabaret mocking the Nazis? Or is the number conflating the cabaret with them? 33 Crosscutting therefore emphasizes the ambiguity of the film's politics, especially in numbers such as "Tiller Girls," in which violence and entertainment are superimposed and almost fused in a much harsher and direct way. This montage technique has a confrontational value, because it clashes scenes of persecution with light entertainment, but it also shows how easy it is to fuse them together in order to dupe the audience. The final laughter of the audience is chilling, because suddenly, laughter is not a collective means of resistance towards oppression, but rather the symbol of "collective unawareness". 34 Contrary to Prince's 1966 production, there is no manifest disavowal of the political situation: 35 the film only widens the discrepancy between the diegetic audience and the heterodiegetic one. To some extent, the politics of the film seem to echo America's inner turmoil towards the end of the Vietnam War: it had brought to light contradictions and fractures within the American society, and perhaps it is possible to interpret Fosse's ambiguities as a parable of this difficulty to "take sides." This "split spectatorship," although present in Prince's production, "is greatly exploited in the film version, with the camera's powerful ability to enunciate and interpolate the spectator in processes of identification and disavowal." 36 Specific cinematographic means therefore add a layer of ambiguity, the same way Fosse's use of dancing in the film contributes to a darker and more cynical vision of love than is usually displayed in film musicals: the film adaptation adds many layers of interpretation to the original stage production. 32 German for "Jew! Jew!" 33 Steven Belletto, "Cabaret and Antifascist Aesthetics", art. cit., p.617. Similarly to the "Tiller Girls" number, the mud-wrestling scene during which the Kit Kat Klub's owner is beaten to death results in the same chilling and confusing dimension. 34 Terri J. Gordon, "Film in the Second Degree," art. cit., p.454. 35 Cliff tells Sally: "If you're not against all this, you're for it-or you might as well be," a line which was not used in the film. 36 Linda Mizejewski, Divine Decadence. Fascism, Female Spectacle, and the Makings of Sally Bowles, Princeton, Princeton University Press, 1992, p.204.

"Willkommen, bienvenue, welcome": back in the theatre

Stephen Harnick's assertion seems once again quite wrong: Fosse's screen adaptation of Cabaret does prove the adaptability of the play and moreover, its malleability, its capacity to evolve and transform according to a director's vision, the medium itself, and the era it is inscribed in. In a letter addressed to Keith Garebian in 2010, Hal Prince mentioned that "Cabaret [had] a life of its own." 37 In this statement, Prince not only referred to the initial stage production and its legacy, but also to the subsequent adaptations-on screen and on stage. Indeed, after Fosse's film, several stage revivals were launched, among which British director Sam Mendes's highly-acclaimed 1998 and 2014 Broadway stagings starring Alan Cumming as the Emcee.

It is important to bear in mind that the malleability of Cabaret is also linked to the subject it tackles (the rise of Nazism), and the fact that the themes it addresses resonate with social evolutions throughout the 20 th and 21 st centuries. The character of Sally Bowles embodies these changes particularly well, as she "has been rewritten to represent each decade's version of a historical dilemma, a haunting of conscience in the years since World War Two." 38 This specific moment in the history of the 20 th century remains an important point of reference for the analysis of current political phenomena, but also for the analysis of human response to the course of History and terrifying events. However, the musical's themes' openness to interpretation inherently contradicts the forcefulness of the director's vision. And this contradiction is once again embodied in the character of Sally Bowles, "whose figure acquired a definitive iconography with Bob Fosse's 1972 film Cabaret" 39 despite her many roles and many portrayals. Because of the mass appeal of cinema and the permanence of film on videotape and DVD, Fosse's version and his choices in representing the characters became the new frame of reference for audiences who had not seen Prince's original staging-or who had forgotten it. Therefore, similarly to Prince's stage production in 1966, Fosse's film became the new point of reference from which reinterpretations and reinventions of Cabaret could emerge. Despite his strong directorial authority, Fosse's liberties with the original version and his inventive use of Prince's staging swept away the impression that the libretto and score were untouchable and immovable monoliths. Subsequent innovative stage recreations such as Sam Mendes's took the same liberties with the source material, "seeing them as living texts to be explored and reinterpreted […]." 40 Sam Mendes's 1998 Broadway recreation of Cabaret, and those that followed, perpetuate Cabaret's resonance with contemporary issues and aesthetics. The protean aspect of the musical is undoubtedly linked with the redefinition and acknowledgment of "the 37 Quoted in Keith Garebian, The Making of Cabaret,op. cit.,p.193. 38 Linda Mizejewski,Divine Decadence,op. cit.,p.4. 39 Ibid., p.3. 40 Miranda Lundskaer-Nielsen, Directors and the New Musical Drama: British and American musical theatre in the 1980s and 1990s, New York, Palgrave Macmillan, 2008, p.109. authorial role of the director" in these "rewrightings". 41 Mendes also imprinted his own vision as a director, and in that perspective, his staging was also very much in keeping with tendencies and aesthetics of the 1990s and beginning of the 2000s, reflecting "the more rebellious, nihilistic, and violent tone of British popular culture 30 years later" that was exemplified on stage by the provocative dimension of in-yer-face theatre and the works of British playwrights such as Anthony Neilson or Sarah Kane, in order to "[reinvent] Prince's idea of the show as a mirror of contemporary developments." 42 The transformation of the characters of Sally Bowles and the Emcee were among the most blatant changes Sam Mendes brought to Cabaret: Sally and the Emcee were interpreted in the 1998 revival by Natasha Richardson, who won a Tony Award for Best Actress, and by Alan Cumming, who also won a Tony Award for Best Actor. Both actors brought forward a "heroin chic" aesthetic, especially Alan Cumming's exhibitionist, vulgar, drug-using Emcee who revealed bruises on his arms when he removed his leather coat, and who was "more androgynous than Grey's demonic doll." 43 Natasha Richardson's Sally was much less glamorous than Minnelli's and much less of a singer; yet she performed one of the most convincing interpretations of Isherwood's Sally Bowles. 44 However, even if Mendes endowed Cabaret with his own directorial vision, he acknowledged the aesthetic and popular appeal of Fosse's version. Mendes's stage readaptations of Cabaret enhance the referential authority of Fosse's film, but also proves a case study for transfers between Hollywood and Broadway. This illustrates the porosity between film and theatre, and perhaps the gradual introduction of cinematic staging and/or film aesthetics within the theatre-similarly to Fosse's "sense of theatre" on film. Indeed, even in terms of personal trajectories, Mendes's revivals of Cabaret are replete with transfers from the film world to the stage world. Mendes himself, as a director, oscillated from the start between stage and film throughout his career. 45 His choreographer and co-director for the 1998 and 2014 Broadway revivals, Rob Marshall, also directed films, even winning an Oscar for Best Picture in 2002 for Chicago (yet another adaptation of a much-loved Fosse musical). Looking beyond these personal histories, the very "flesh" of Cabaret (the book, the score, the characters and even the primary sources) becomes a point of "passage" from one pole (the film) to the other (the stage) in Mendes's revival. For instance, the score played upon viewers' expectations, by replacing some of the songs that were present in the libretto by songs specifically created for the film ("Mein Herr" and "Maybe This Time"). This element 41 Ibid.,p.110. 42 Ibid.,p.129. 43 Keith Garebian, The Making of Cabaret,op. cit.,p.173. 44 Ibid.,p.169. 45 Sam Mendes is not the first director to alternate between film and theatre. Julie Taymor, an American film and stage director (best known for her films Frida, 2002, Across the Universe, 2007, and The Tempest, 2010, as well as her dazzling 1997 Broadway production of the musical The Lion King) is another good example of the circulation between film and theatre, all the more so as her stage productions display a manifest cinematic quality.

highlights "the importance of film adaptations in building audiences for the [revivals]", 46 but also the circularity of musicals like Cabaret, which create points of connexion from one version to another by soliciting the audience's knowledge of the songs. Once again, the character of Sally Bowles proves a peculiar point of passage between Hollywood and Broadway, as some of the actresses who reprised the role in Mendes's most recent revivals on stage were Hollywood actresses, such as Michelle Williams and Emma Stone, who both starred in the 2014 Broadway revival. Cinematography and the filmic treatment of Cabaret by Fosse would be a definite inspiration to Mendes and Marshall's staging: the luminous frame overlooking the stage, and within which the Kit Kat Klub's orchestra performed, framed the viewer's eyes, similarly to the frame of a screen. This desire to direct the spectator's eyes, as would a camera, also became visible in the choreography. Rob Marshall took up Fosse's gesture and dance vocabulary, insisting on small gestures and details (undulating fingers and pelvic thrusts) that were highlighted by lighting effects. For instance, as the first notes of "Willkommen" started to play, a light would circle the Emcee's hand emerging from behind a door, its fingers beckoning the audience to come in. And in the 1993 original Mendes London production (which prompted the very successful first Broadway revival), Mendes gave Fosse a humorous nudge during the number "Mein Herr," starring Jane Horrocks as Sally. Sally would sing "Mein Herr," holding a heart-shaped lollipop and sitting on a gigantic chair, as a playful reference to Fosse's own source of inspiration for the choreography of the number in the film (Marlene Dietrich in The Blue Angel). As Fosse's version offered a gradual darkening of the tone of the musical and a more ambiguous moral stance, Mendes accelerated this move towards darkness, ambivalence and shocking sexuality, notably by removing any trace of glitz and glamour that was left and replacing it with a certain harshness. The ambiguous role of the audience was reinforced by Mendes's introduction of Cabaret's audience as the Kit Kat Klub's audience, sitting at café tables just as in a regular cabaret (even renaming the theatre that would host its 1998 revival "The Kit Kat Klub"): the confusion and blurring of boundaries between the two worlds became even more visible than with Fosse's systematic intercutting. Mendes pushed forward the complexities of the subject (the rise of the Nazis conflated with a moral decadence and indifference to the political situation), shocking and provoking his contemporary audiences by ending the musical with the Emcee wearing a concentration camp uniform (with a pink triangle), before throwing himself on an imaginary electric fence. Even if Prince and Fosse's versions entailed no such thing as a happy ending, Mendes's stance is implacable. This harsh and shocking ending finishes off the musical's no-longer-canonical happy ending by leaving no room for escape and/or survival. But Mendes's radical choice also highlighted issues that had been avoided by Fosse's film, such as the representation of homosexuality and queerness: this "finale" takes advantage of the libretto's blanks in interpretation 47 and weighs on the audience's reaction to this stretch of interpretation. Mendes's gesture also re-placed Cabaret within the frame of contemporary issues tackled by other musicals, such as Rent (1996), for instance, with its open discussion of homosexuality and AIDS. Amidst the crisis and controversies stirred by the media frenzy surrounding the epidemic, it is highly probable that Mendes's production aimed to add this extra political layer in order to inscribe Cabaret's politics within an immediate moment. Mendes's shocking and harsh production is one example of Cabaret's gradual destruction of the genre's "myth of entertainment," but also of its shifting politics, adaptation after adaptation.

The many lives of Cabaret on screen and on stage have precipitated the musical's redefinition of the genre. This re-definition was perhaps inherent to the story and its lacklustre yet intriguing characters. By pushing further and further its sombre politics and by gradually un-polishing the performances, film and stage adaptations of Cabaret shed light upon this musical's disruptive capacity. Moreover, each adaptation, first on screen, and then back on the stage, was already a disruption of a preceding version, deeply marked by contemporary sensibilities, but also by the director's vision. Indeed, Fosse's film as well as Sam Mendes's stage revivals confirmed what Hal Prince's original 1966 production had enunciated-that the director's role was of paramount importance in order to create innovative musicals.

Fosse's Cabaret endowed the musical with a darker and more ambiguous interpretation than Prince's, disrupting most of the film musical's conventions. By allowing the realm of cinema to pervade and invade what used to be a theatrical space, making it more realistic, Fosse's screen adaptation made the musical acknowledge its theatrical dimension. His cinematic aesthetics, such as choreography and montage, surely inspired later stage revivals, especially those directed by Sam Mendes. The film's accessibility for audiences also emphasized a "co-dependency" between film adaptations and stage revivals-the latter being often made to "resemble more closely the film versions". 48 If Mendes went further than Fosse on many levels, it is because the screen adaptation itself allowed for a complete transformation of the material, but also because of shifting context and audience, thus proving that Cabaret could generate new meaning.

The circularity of Cabaret, from stage to screen and back on the stage again, shows how fertile these circulations between mediums are. The assumed inadaptability of Cabaret proves even more amusing if we consider its contemporary meaning, which transcends 1930s Germany and still addresses 20 th -and 21 st -century issues, following the evolutions of the 1970s, 1990s and 2000s. Therefore, more than circularity, perhaps one could read Cabaret as qu'il le trahit, puisque précisément le texte ne dit rien de la gestuelle et de la proxémique des deux personnages, qui reste à inventer." "… the stage director pushes the limits of the text. But neither does he force nor betray it, precisely because the text bears no mention of the gestural or proxemic code between the two characters, which has yet to be invented." In Florence Naugrette, Le Plaisir du spectateur de théâtre, Rosny-sous-Bois, Éd. Bréal, 2002, p.168. 48 Raymond Knapp and Mitchell Morris, "The Filmed Musical," art. cit., p.142. a musical of circulation, whose numerous adaptations throughout the years have had the capacity to echo other musicals which also challenged the traditional formulas of the genre. The disruptive dimension of Cabaret's shifting politics is the one element that allows these adaptations to exit the constraints of the musical and to transform the genre, by playing on audience expectations and reactions. Cabaret's many adaptations, none of them quite resembling one another, emphasize the unfixed dimension of this musical, constantly redefined, and constantly redefining. LONG, Robert Emmet, Broadway, the Golden Years: Jerome Robbins and the Great Choreographer-Directors, 1940 to the Present, A&C Black, 2003. LUNDSKAER-NIELSEN, Miranda, Directors and the New Musical Drama: British and American Musical Theatre in the 1980s and 90s. New York, Palgrave Macmillan, 2008. MASTEROFF, Joe, et al., Cabaret. New York, Random House, 1967. multiples réinventions. Ceci nous amènera à questionner les circulations entre théâtre et cinéma, notamment à travers ces réinventions scéniques que sont les revivals.

Mots-clés : comédie musicale ; film musical ; Cabaret ; adaptation ; Harold Prince ; Bob Fosse ; Sam Mendes ; metteur/se en scène ; réalisateur/trice

  BIBLIOGRAPHY ALTMAN, Rick, The American Film Musical. Bloomington, Indiana University Press, 1987. BELLETTO, Steven, « Cabaret and Antifascist Aesthetics ». Criticism 50.4 (2008): 609-630. BRANTLEY, Ben, « Old Chums Return, Where Club Is Home », The New York Times, 24 avril 2014. BUMILLER, Elisabeth, « A Cooler, More Self-Aware Sally Bowles ». The New York Times, 15 mars 1998. CHALAYE, Sylvie et MOUËLLIC Gilles, Comédie musicale, les jeux du désir: de l'âge d'or aux reminiscences, Rennes, Presses universitaires de Rennes, 2008. CLARK, Randy, « Bending the genre: The stage and screen versions of Cabaret », Literature/Film Quarterly 19:1 (1991), pp.51-59. FEUER, Jane, « The Self-reflective Musical and the Myth of Entertainment », Quarterly Review of Film Studies, 2:3 (2009), pp.313-326. FOSSE, Bob. Cabaret. Burbank [CA], Warner Home Video, 1972. FRANKEL, Haskel. « THEATER Go to the "Cabaret," My Friends », The New York Times, 12 août 1979. GAREBIAN, Keith, The Making of Cabaret, New York, Oxford University Press, 2011. GORDON, Terri J., « Film in the Second Degree: "Cabaret" and the Dark Side of Laughter », Proceedings of the American Philosophical Society, 152:4 (2008), pp.440-465. GOTTFRIED, Martin, All His Jazz: The Life & Death of Bob Fosse. New York [NY], Bantam Books, 1990. GREENSPUN, Roger, « Movie Review --Cabaret », The New York Times, 14 février 1972. HIRSCH, Foster, Harold Prince and the American Musical Theatre, New York, Cambridge University Press, 1989. KNAPP, Raymond, MORRIS, Mitchell, et WOLF, Stacy Ellen, The Oxford Handbook of the American Musical, New York, Oxford University Press, 2011.

  John Kenrick, "History of the Musical Stage -1960s III: The World Turned Upside Down", Musicals 101, https://www.musicals101.com/1960bway3.htm, visited on April 3 rd , 2017, and Jack Poggi, Theater in America: The Impact of Economic Forces, Ithaca, N.Y., Cornell University Press, 1968. Sweet Charity and the Feminist Utopia of Broadway Musicals",

7

Stacy

Wolf, "Something Better Than This:

  25 "[…] his choreography draws the viewer's eye to the smallest and subtlest nuances of the body through precise gestures, a movement of the ribs, the shrug of the shoulder, a tilt of the pelvis, or a facial expression." In Cathy Young, "Hand on the Pulse: Dancing with Bob Fosse," Dance Chronicle, vol. 32, no. 1, 2009, p.176. See also Martin Gottfried, All His Jazz: The Life and Death of Bob Fosse, New York, Bantam Books, 1990. 26 "Dans ces films, la syncope est partout, le rythme est saccadé, empêchant tout élan lyrique, poétique, ramenant toute l'attention au geste et à son exécution." "In these films, syncopation is everywhere: the rhythm is twitchy, which cancels every possible flight of lyricism or poetical attempt, and the spectator's attention is constantly drawn back to the gesture and its execution." In Roxane Hamery, "Bob Fosse : les passions despotiques", in Sylvie Chalaye and Gilles Mouëllic (dir.), Comédie musicale, les jeux du désir : de l'âge d'or aux réminiscences, Rennes, Presses Universitaires de Renne, 2008, p.116. 27 Rick Altman, The American FilmMusical, Bloomington, Indiana University Press, 1987, p.82. 28 For Altman, more than the plot, "the oppositions developed in the seemingly gratuitous song-and-dance number, […] are instrumental in establishing the structure and meaning of the film. Only when we identify the film's constitutive dualities can we discover the film's function." Ibid., p.27.characters like Hodel and Perchik to fall in love and express it. But like Cabaret, more and more musicals, on stage and on screen were starting to upset this principle (amidst the sexual revolution and its challenging representations of the male and female pairing) such as Stephen Sondheim's Company (1970), as well as Fosse's own stage and screen versions of Sweet

Fosse's Cabaret also won 8 Oscars, out of 10 nominations at the 1973 Academy Awards, among which Best Director.

Randy Clark, "Bending the Genre: The Stage and Screen Versions ofCabaret", Literature Film Quarterly, vol. 19, no. 1, 1991, p.55.

Most critics were less than charmed by Haworth's performance, especially because of her lack of singing capabilities (even though this was the reason why Prince chose her, out of realism, for the role of a secondrate nightclub singer such as Sally Bowles). See Keith Garebian, The Making ofCabaret, op. cit., p.124.

 15 Raymond Knapp and Mitchell Morris, "The Filmed Musical," in Raymond Knapp, MitchellMorris and Stacy Wolf (dir.), The Oxford Handbook of the AmericanMusical, op. cit.,

Keith Garebian, The Making ofCabaret, op. cit., p.151.

Raymond Knapp and Mitchell Morris, "The Filmed Musical", art. cit.,

"No one believe in those actresses who start singing or twirling as they wash the dishes or run errands anymore. This is why Cabaret […] takes place in the world of music hall." In Fabienne Pascaud, "Entretien avec Bob Fosse", Télérama, no. 1585, May 28 th ,

1980, p.95. 19 Steven Belletto, "Cabaret and Antifascist Aesthetics", Criticism, vol. 50, no. 4, Fall 2008, p.612. 20 Aronson and Prince mostly had the Civil Rights movement in mind. See Keith Garebian, The Making ofCabaret, op. cit.,

Roger Greenspun, "Movie Review-Cabaret", art. cit.

Terri J. Gordon, "Film in the Second Degree: 'Cabaret' and the Dark Side of Laughter," Proceedings of the American PhilosophicalSociety, vol. 152, no. 4, 2008, p.444.

Keith Garebian, The Making ofCabaret, op. cit., p.40.

Raymond Knapp and Mitchell Morris, "The Filmed Musical," art. cit., p.142.

About a staging of Lorenzaccio in which Lorenzo and the Duke are presented as gay, Florence Naugrette writes: "[…] le metteur en scène pousse le texte dans ses retranchements. On ne saurait dire qu'il le force ou


Maher Maroua El Glaoui

El Glaoui

Christian Jelsch

Emmanuel Aubert

Cherif Frederic Lefebvre

Ben Nasr

Maroua El Glaoui

Maher El Glaoui

Frédéric Lefebvre

Ben Chérif

Nasr

A Hirshfeld surface analysis, crystal structure and spectroscopic properties of new Zn(II) complex with N-aminoethylpiperazine ligand

Keywords: Zn(II) complex, X-ray diffraction, NMR spectroscopy, Ultraviolet-visible (UVvis) spectroscopy, Hirshfeld surface analysis, Coordination compound

établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

In recent years, there has been an increasing interest in organic-inorganic compounds, whose combination may convey the synergy properties of both moieties into one hybrid compound. This enables them to exhibit some interesting crystal structures and properties such as second-order nonlinear optical (NLO) response, magnetic, electronic, conductivity, luminescence and ferroelectric properties [1 -9]. Additionally investigation of the Zn(II) frameworks in terms of photoluminescence was thoroughly performed recently [START_REF] Konar | Synthesis, crystal structure, spectroscopic and photoluminescence studies of manganese(II), cobalt(II), cadmium(II), zinc(II) and copper(II) complexes with a pyrazole derived Schiff base ligand[END_REF][START_REF] Ding | Syntheses and structures of tetranuclear Zn(II) complexes with in situ generated macrocyclic Schiff base ligands: Applications in Zn 2+ sensing[END_REF].

Moreover, in organic-inorganic hybrid metal halides, hydrogen bonds play an important role in stabilizing the frameworks of the cations and their counter inorganic species. The energy of N-H… hydrogen bonds and their possible role in supramolecular chemistry continue to attach much attention [START_REF] Brammer | Hydrogen bonding and perhalometallate ions: A supramolecular synthetic strategy for new inorganic materials[END_REF]. Therefore, in this paper we present the synthesis, structural and spectral characterization of (C6H18N3)[ZnCl4]Cl.

Experimental

Synthesis

The organic-inorganic hybrid compound, (C6H18N3)[ZnCl4]Cl, was prepared by reaction of N-aminoethylpiperazine, C6H15N3, and Zinc chloride. First, ZnCl2 (1 mmol; 0.17 g) was added to an N-aminoethylpiperazine (1 mmol; 0.19 g) solution dissolved in 15 mL of absolute ethanol. The resulting solution was then acidified with 1 mL of concentrated HCl and allowed to evaporate slowly at room temperature. Colorless block like crystals of (C6H18N3)[ZnCl4]Cl were formed after two weeks (yield, 87.7%).

The reactions sequence for the synthesis is shown in the following equation: C6H15N3 + ZnCl2 +3 HCl → (C6H18N3)[ZnCl4]Cl 1.2. Crystal structure determination Single crystals were carefully selected under a microscope and mounted on a Mitegen micromesh with the help of a trace of mineral oil. X-ray diffraction data were collected at 100 K on a Bruker AXS SMART APEX CCD diffractometer using the  scan technique with MoKα radiation (λ = 0.7107 Å). Diffraction data were collected, the unit cell determined, and the data integrated and corrected for absorption and other systematic errors using the APEX2 suite of programs [START_REF]Bruker Apex2[END_REF]. SHELXS-97 [14] was used to solve the structure using direct methods and SHELTXL6.14 [START_REF]Bruker Advanced X-ray Solutions, SHELXTL (Version 6.14[END_REF], SHELXL2013 [START_REF] Sheldrick | SHELXL2013[END_REF] and SHELXLE [START_REF] Hübschle | ShelXle: a Qt graphical user interface for SHELXL[END_REF] were used for refinement.

The drawings were made with Diamond [START_REF] Brandenburg | Diamond Version 2.0 Impact GbR[END_REF]. The final anisotropic full-matrix least squares resulted in a convergence of the R factor at 0.015, Rw = 0.037. Crystal data and experimental parameters used for the intensity data collection are summarized in Table 1.

IR spectroscopy

The IR spectra were recorded in the range 4000 -400 cm -1 with a ''Perkin-Elmer FTIR'' spectrophotometer 1000 using samples dispersed in spectroscopically pure KBr pressed into a pellet.

Raman measurements

For Raman measurements, a good transparent single crystal of (C6H18N3)[ZnCl4]Cl was selected and the Raman scattering spectrum was performed using HORIBA Scientific spectrometer (lab. RAM HR) equipped with Laser source (632 nm) and CCD detector with standard attachment in the frequency range 100 -3500 cm -1 at room temperature.

Electronic spectrum

The electronic spectrum was recorded on a Perkin-Elmer Lambda 950 spectrophotometer within the range 200 -800 nm.

Results and discussions

Structure description

The asymmetric unit of the title compound is formed by one 1-amonioethylpiperazine-1, 4-diium trication, one tetrachlorozincate dianion and one isolated chloride anion (Fig. 1).

In the structural arrangement, the inorganic ions, ZnCl4 2-, NH3 + , NH2 + and Cl -, are interconnected through N-HCl hydrogen bonds to form layers parallel to the (a, b) plane (Fig. S1) and located at z = ½ (Fig. 2).

The organic group and the free Cl -anions are interconnected via N-H…Cl and C-H…Cl hydrogen bonds to form layers parallel to the (b, c) plane (Fig. S2). These layers, situated at x = 0 (Fig. S3), are interconnected by the ZnCl4 2-anions via N-H…Cl and C-H…Cl hydrogen bonds to form the crystal packing (Fig. S4).

The complex [ZnCl4] 2-anion is distorted due to its involvement in hydrogen-bonding interactions. The [ZnCl4] 2-and Cl -anions are well separated by Van der Waals contacts and consequently there is no basis for describing the Zn(II) species as a distorted [ZnCl5] 3-anion.

Geometry and coordination of the tetrachlorozincate dianion

The geometry of ZnCl4 verifies the reported relation (Table 2). The Zn-Cl distances vary between 2.2582 (4) and 2.2813 (5) Å with a mean value of 2.268 Å. The Cl-Zn-Cl angle values are in the 104.667 (16) -112.083 (16)° range with a mean value of 109.494° and indicate relatively little distortion from a regular tetrahedron. Taking into account the geometrical characteristics of the entities and considering the calculated average values of the Baur distortion indices (DI) deduced from the following formula [START_REF] Baur | The geometry of polyhedral distortions. Predictive relationships for the phosphate group[END_REF]:

     1 1 1 ) ( n i m m i d n d d Cl Zn DI       2 1 2 ) ( n i m m i a n a a Cl Zn Cl DI
Where dm is the mean value for (Zn-Cl) distances and am the mean value for (Cl-Zn-Cl) angles. DI (Zn-Cl) = 3.8.10 -3 , DI (Cl-Zn-Cl) = 0.025, with n1 = 4 and n2= 6.

The low values of these indices are possibly due to the fact that all chlorine atoms are involved in weak hydrogen bonds.

Geometry and coordination of the organic cation

The organic group is located in the (b, c) plane (Fig. S2). Table 2 reports the main geometrical features of the [C6H18N3] 3+ cations. The C-N bond lengths vary from 1.488(2) to 1.507(2) Å. The C-C bond lengths vary from 1.514 (2) to 1.515 (2) Å. These values are in agreement with those found in related compounds [START_REF] Issaoui | Synthesis, Crystal Structure, Magnetism, Band Structure and Density of States of [C6H18N3]ClCoCl4[END_REF].

The conformation of the piperazine-diium six-membered ring can be described in terms of Cremer and Pople puckering coordinates [START_REF] Cremer | A General Definition of Ring Puckering Coordinates[END_REF], i.e., evaluating the parameters Q (total puckering amplitude), q2, q3, θ and φ. The calculated values for N1-C1-C2-N3-C4-C6 ring are as follows: Q = 0.565 Ǻ, q2 = 0.0094 Ǻ, q3 = -0.565 Ǻ, θ = 179.04° and φ = -78.12° corresponding to the structure of the most stable chair conformation.

Vibrational studies

The FTIR and Raman spectra of crystalline (C6H18N3)[ZnCl4]Cl are displayed in Figs.

S5 and S6 respectively and the vibrational assignments are listed in Table 4.

The comparison of the IR spectrum of the title compound with that of the pure amine (Fig. S5) shows, in particular, that the presence of the tetrachlorozincate anion shifts the bands related to the NH2 and NH groups of the amine, situated at 3382 and 3287 cm -1 , at lower wavenumbers, between 3121 and 3078 cm -1 . This shift towards the low frequencies is attributed to the formation of hydrogen bonds N-H…Cl in the salt.

The most representative and characteristic vibrational modes of this compound can be compared to those of similar compounds [22 -29]. The asymmetric and symmetric modes of NH3 stretching vibration are observed at 3121 and 3078 cm -1 in FTIR. N-H and C-H asymmetric stretching vibrations are assigned to the peaks observed at 2982 cm -1 in FTIR, while the peak at 2447 cm -1 in IR is assigned to N-H and C-H symmetric stretching vibrations. The peaks found at 1570 and 1507 cm -1 in FTIR and at 1574, 1557, 1500 and 1482 cm -1 in Raman are assigned to NH2 wagging and CH2 scissoring vibrations. Considering the CH2 group vibrations, the deformation of CH2 and N-H deformation are observed at 1470 and 1445 cm -1 in FTIR, respectively and at 1470 and 1440 cm -1 in Raman. The peaks at 1396 and 1335 cm -1 in IR are assigned to CH2 wagging vibrations and are observed at 1402, 1394, 1334 and 1312 cm -1 in Raman. The CH2 and NH2 twisting vibrations modes are found at 1286 cm -1 in FTIR and 1290, 1281 and 1214 cm -1 in Raman. The observed peaks at 1181, 1151, 1077 and 1048 cm -1 in FTIR and in Raman at 1192, 1147, 1046 and 1036 cm -1 correspond to CH2 rocking and C-C stretching vibrations. (C-C), (N-H) and (C-N) stretching, (C-N-H) bending and CH3 rocking are identified in the strip area located between 1006 and 747 cm -1 in IR and between 1003 and 744 cm -1 in Raman. Further, the peak that appeared at 622 cm -1 in IR and the peaks between 620 and 387 cm -1 in Raman are assigned to the C-N-C and C-C-N deformation. The low frequency Raman absorption peaks occurring at 299, 282, 123 and 110 cm -1 are due to internal vibrations of ZnCl4 2-ion.

The calculated IR spectrum between 500 and 4000 cm -1 is shown in Fig. S7 and is very similar to the experimental one. A close agreement between the experimental and calculated wave numbers is mostly achieved in the fingerprint region as shown in Fig. S8. Thus, the precision is well-sufficient to assign the experimental frequencies and to confirm the attributions proposed above. [31], (C7H8N3)[CdI4] [START_REF] Kessentini | Synthesis, crystal structure, vibrational spectra, optical properties and theoretical investigation of bis (2aminobenzimidazolium) tetraiodocadmate[END_REF]. The nethermost energy absorption peaks at 385 nm is caused by band gap absorption and it is attributed to the excitation of free electron-hole pairs within the [ZnCl4] 2-inorganic chain. This peak is mostly due to a photo-induced exciton constituted by the transition from the top of the valence band including of Cl(3p) orbital to the bottom of the Zn(4s) conduction band (absorption between Cl(3p) and Zn(4s) (band to band)). This suggests that the compound behaves as semiconductor material and is compatible with the color of the crystal. The bands with maximum energies at 225 and 285 nm can be assigned to the absorption of a highest energetic level in the conduction band.

UV-visible spectroscopy

Hirshfeld surface and contacts enrichment ratios

The Hirshfeld surface of the title compound was generated using Crystal Explorer [START_REF] Wolff | CRYSTAL-EXPLORER 3.0[END_REF].

The Hirshfeld surface is used to identify the intermolecular interactions including H…Cl, H…H, Cl…Cl contacts. Three-dimensional (3D) Hirshfeld surface maps are generated with dnorm using a red-white-blue color scheme, indicating shorter contacts, Van der Waals contacts, and longer contacts, respectively, and the decomposed two dimensional fingerprint plots generated using de and di distances lead to analyze all of the intermolecular contacts and to summarize the nature and type of all intermolecular contacts in the crystal structure.

The enrichment ratios [START_REF] Jelsch | Likelihood of atom-atom contacts in crystal structures of halogenated organic compounds[END_REF] of contacts between the different chemical species were computed in order to highlight which contacts are favored and are likely to be the crystal driving force.

The Hirshfeld surface was computed around the independent organic cation, one ZnCl4 anion, and one chloride anion (Fig. 3 (a, b andc)). The intensive red hot spots on the surface colored according to dnorm correspond to hydrogen bonds with neighboring molecules. The 2D fingerprint plots can be decomposed to highlight a particular atom pair close contacts and to enable the separation of contributions from different interactions of each subgroup of the asymmetric unit (Fig. S10, S11 and S12).

Globally the H and Cl chemical types constitute the large majority (46 and 47%) of the Hirshfeld surface on the three ions present the asymmetric unit. The organic cation surface is covered by 95% of hydrogen which mostly interacts with chloride atoms, as can be seen in Fig. 4. The intermolecular H…Cl contacts are predominant as they constitute more than three quarters of the total interaction surface (Table 5). The hydrogen atoms (Hn, Hc) bound to N and C are distinguished in Table 5, as their electrostatic properties are different. The Hc…Cl contacts, which are weak hydrogen bonds, constitute nearly half of the contact surface. The strong H-bonds Hn…Cl -are more enriched (E=2.0) than the weaker Hc…Cl -interactions (E=1.6). There are indeed ten N-H…Cl and ten C-H…Cl hydrogen bonds in the crystal structure (Table 3, Fig. S10). The Hn…Cl and, to a lesser extent, the Hc…Cl contacts are electrostatically favorable due to the complementary partial charges δ + of H and δ -of chloride atoms.

The Zn…Hc contacts are the most enriched (E=2.3) but constitute only 5.4% of contacts; they are presumably a consequence of their proximity with the large proportion of Zn…Cl -contacts. All self-contacts, including the hydrophobic interaction Hc…Hc are significantly avoided with low E<0.45 values. Chloride and hydrogen atoms constitute both nearly one half of the Hirshfeld surface; as consequence there is a good surface complementarity between H-bond acceptors and donors while hydrophobic contacts (mainly Hc…Hc) between organic cations represent only 5% of the contact surface. In summary, the crystal packing is essentially maintained by attractive and favored strong Hn…Cl -and weak Hc…Cl -hydrogen bonds.

Quantum mechanical study

Quantum chemical calculation was performed from the crystal data with DFT method at the 6-311++G(d,p) basis set, by using the Gaussian 09 program. Fig. 5 clearly shows that the highest occupied orbital (HOMO) is mainly localized on the CH2 groups, while the lowest unoccupied orbital (LUMO) is mainly localized on the N-H groups. The large HOMO-LUMO gap of 10.2 eV implies high kinetic stability and low chemical reactivity [START_REF] Seth | Crystal structure and DFT calculations of andrographiside[END_REF][START_REF] Seth | Structural elucidation and electronic properties of two pyrazole derivatives: A combined X-ray, Hirshfeld surface analyses and quantum mechanical study[END_REF], because it is energetically unfavorable to add electrons to a high-lying LUMO or to extract electrons from a low-lying HOMO [START_REF] Wang | Synthesis, Structure and Theoretical Calculation of Imidazolium 3, 5-Dinitrobenzoate[END_REF].

Beside these isolated molecule computations, periodic DFT calculations were also undertaken using the Castep 8.0 software [START_REF] Clark | First principles methods using CASTEP[END_REF]. Starting with the experimental X-ray structure geometry, positions of all atoms were optimized while keeping the unit cell parameters fixed to the corresponding experimental values. The PBE functional was selected, completed with Grimme dispersion correction [START_REF] Grimme | Semiempirical GGA-type density functional constructed with a long-range dispersion correction[END_REF]; on-the-fly ultrasoft pseudopotentials were used, and a plane wave cutoff of 600 eV was selected and tested for geometry convergence, together with a kpoint spacing of 0.03 Å -1 leading to 26 points for the sampling of the Brillouin zone. The resulting optimized structure is very close to the experimental one as shown by the superposition of the two (Fig. 6), the major differences being the positions of hydrogen atoms, which are too close to their covalently bonded C, N heavy atoms in the X-ray structure, as expected.

NMR results

The 13 C CP-MAS NMR spectrum of (C6H18N3)[ZnCl4]Cl is shown in Fig. S13. It exhibits six well-resolved resonances corresponding to the six crystallographically independent carbon atoms. This is in agreement with only one organic molecule being present in the asymmetric unit cell as revealed by the X-ray structure determination.

The 15 N CP-MAS NMR spectrum of the title compound (Fig. S14) is also in good agreement with the X-ray structure. Indeed, it exhibits well-defined signals with an intensity ratio of 1:2 at -361.9 and -358.1 ppm corresponding to the three crystallographic independent nitrogen atoms, in agreement with only one organic molecule in the asymmetric part of the unit cell.

Density functional theory (DFT) calculations were undertaken in order to assign the NMR resonances to the different crystallographic non-equivalent carbon and nitrogen atoms of the unit cell. These calculations were made at the B3LYP/6-311++G** level. The different atoms were labeled as depicted below:

The calculations were made on the organic cation after optimization of the position of the protons and the theoretical chemical shifts were subtracted from those of the reference (tetramethylsilane for carbon with δexp = 0 ppm and glycine for nitrogen with δexp = -347.2 ppm and δth = -238.0 ppm) calculated at the same level of theory.

The results are listed on Table 6 and Fig. 7. Clearly, there is a very good agreement between the experimental and the theoretical values calculated after optimization of the position of the protons, allowing unambiguously the attribution of the different NMR signals, even though some calculated values for the isotropic chemical shifts are far away from the experimental ones.

It is worth noticing that the discrepancy between the calculated and experimental values is mainly due to the fact that an isolated molecule was taken into account. A better agreement was then obtained by computing the isotropic part of the NMR shielding tensors by periodic DFT calculations using the Castep 8.0 software. Indeed, the coefficient of determination in the linear regression analysis with respect to the experimental values rose to 0.9996 (as compared to 0.9643 for the isolated molecule calculation).

Concluding remarks

We

Supplementary data

Crystallographic data for the structural analysis have been deposited at the Cambridge Crystallographic Data Centre, CCDC No 1509981. These data can be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK: fax: (+44) 01223-336-033; e-mail: deposit@ccdc.cam.ac.

Fig

  Fig. S9 shows the experimental UV-Vis absorption spectrum of (C6H18N3)[ZnCl4]Cl at

  have developed new (C6H18N3)[ZnCl4]Cl crystals, which show the monoclinic space group P21 with a minimal tetrahedral distortion of the [ZnCl4] 2-ion. In the structure, the different inorganic ions are interconnected through N-HCl hydrogen bonds to form layers parallel to the (a, b) plane. The piperazinediium six-membered ring adopts the most stable chair conformation. The crystal structure is stabilized via the various types of hydrogen bonding interactions, N-HCl and C-HCl. The Hirshfeld surface analysis reveals that the intermolecular H…Cl contacts are predominant. NMR signals are in full agreement with the crystallographic data. DFT calculations allow the attribution of the experimental NMR lines and of IR bands at low frequencies.

Figures

  Figures

Fig. 1

 1 Fig. 1

A

  view of the asymmetric unit in the crystal structure of the title compound showing the atom-numbering scheme and displacement ellipsoids drawn at the 50% probability level. The dotted lines indicate hydrogen bonds.

Fig. 2

 2 Fig. 2 Projection of a layer situated at z = ½ of the crystal structure of (C6H18N3)[ZnCl4]Cl in the (a, c) plane. The dotted lines indicate hydrogen bonds.

Fig. 3

 3 Fig.3

Fig. 4

 4 Fig. 4 Hirshfeld surface around the three independent moieties in the crystal.

Fig. 5 FrontierFig. 6

 56 Fig. 5

Fig. 7 Comparison

 7 Fig. 7

Fig. S2 Projection

 S2 Fig. S2

Fig. S3

 S3 Fig. S3

Fig. S4 Projection

 S4 Fig. S4

Fig. S5 Infrared

 S5 Fig. S5

Fig. S6 Raman

 S6 Fig. S6

Fig. S7

 S7 Fig. S7 Calculated IR absorption spectrum of (C6H18N3)[ZnCl4]Cl.

Fig. S8

 S8 Fig. S8 Comparison between experimental and calculated frequencies of (C6H18N3)[ZnCl4]Cl.

Fig. S9

 S9 Fig. S9 Variation of the absorbance with wavelength for (C6H18N3)[ZnCl4]Cl.

Fig. S10

 S10 Fig. S10 2D fingerprint plots of the organic cation where areas of different intermolecular contacts are clearly shown; de and di are the distances to the nearest atom exterior and interior to the surface.

Fig. S11

 S11 Fig. S11 2D fingerprint plots of the inorganic anion ZnCl4.

Fig. S12 2D

 S12 Fig. S12

Fig. S13 13 C

 13 Fig. S13

Fig. S14 15 N

 15 Fig. S14

Table 4

 4 Observed and calculated frequencies (cm -1 ) of (C6H18N3)[ZnCl4]Cl.

	Wavenumber FTIR (cm -1 )	Raman (cm -1 )	Assignements
	3121		NH3 asymmetric and symmetric
	3078		stretching
	2982 2447		NH2,(N-H) and (C-H) stretching
	1570	1574
	1507	1557 1500	NH2 wagging and CH2 scissoring
		1482
	1470	1470	(CH2) deformation
	1445	1440	(N-H) deformation
	1396	1402
	1335	1394 1334	CH2 wagging
		1312
	1286	1290
		1281	NH2 and CH2 twisting
		1214
	1181	1192
	1151 1077	1147 1046	CH2 rockingand (C-C) stretching
	1048	1036
	1006	1003
	979	978
	947 899 850	944 896 866	(C-C), (N-H) and (C-N) stretching + CH3 rockingand (C-N-H) bending
	747	848
		820
		744
	622	620
		519
		484	(C-N-C) and (C-C-N) deformation
		420
		387
		299
		282
		124	Internal vibrations of ZnCl4 2-
		123
		110

Table 5

 5 Chemical proportions on the Hirshfeld surface of the three entities: organic cation, ZnCl4 2-anion and chloride anion. Actual contacts and their enrichment in the crystal of the title compound are also given (C and N atoms omitted).

	atom	Cl	Hn	Hc	Zn	C	N
	% surface	46.2	15.3	32.3	3.7	2.2 0.2
	Contacts %	Cl	Hn	Hc	Zn
	Cl	6.7
	H	28.3	0.03
	Hc	47.9	0.5	4.4
	Zn	0.9	1.2	5.4	0.0
	Enrichment	Cl	Hn	Hc	Zn
	Cl	0.30
	Hn	1.98	0.01
	Hc	1.61	0.05	0.45
	Zn	0.25	1.08	2.26	0.00

Table 6

 6 Comparison of calculated and experimental chemical shift values of carbon and nitrogen atoms in the title compound.

	Atoms	Calculated (ppm)	Experimental (ppm)
		Gas phase	Periodic phase
	C1	41.8	38.3	38.6
	C2	49.1	44.9	44.9
	C3	56.9	49.8	49.4
	C4	43.2	40.1	40.1
	C5	53.6	49.1	48.9
	C6	40.6	35.3	35.8
	N1	-310	-363	-358
	N2	-302.5	-355	-358
	N3	-324.5	-359	-362

Acknowledgment

Thanks to Professor Matthias Zeller of Youngstown State University (USA) for his fruitful collaboration. The diffractometer was funded by NSF grat 0087120, by Ohio Board of Reagents grant CAP-491, and by YSU. This work was granted access to the HPC resources of TGCC/CINES/IDRIS under the allocation 2017-A0010807449 made by GENCI.

Supplementary Materials

Fig. S1 Projection, along the a-axis, of a layer in the inorganic structure of the title compound. The dotted lines indicate hydrogen bonds.


M C W Wolf

A J H Frijns

S V Nedea

R Enright

A Marie-Curie-ITN within H2020 MIGRATE2017:154795 MOLECULAR WATER LAYER EVAPORATION & CONDENSATION

Keywords: Molecular dynamics, nanopore evaporation, two-phase cooling

The past decade has seen a considerable growth in portable devices with mobile connectivity. This growth has been enabled by the development of high capacity telecommunication networks globally. Individuals require high data transfer capabilities to remotely stream large information sets (i.e. HD video) and this is leading to greater demands for next generation networks (i.e. 5G). To ensure this growth continues, hardware devices must be smaller, more energy-efficient and provide greater functionality. This requirement poses a thermal management challenge, increasing heat transfer density significantly. Novel materials and cooling methods, which are engineered at the micro-and nanoscale, are necessary to address this.

The overall aim of this project is to examine and maximize the heat transfer performance capabilities in an enclosed two-phase micro-system architecture.

Introduction

A very promising cooling technique for the increasing heat transfer density is the method depicted in fig. 1. In this two-phase cooling system, the liquid phase evaporates from the nanopores to the gas phase [START_REF] Hanks | Evaporation from Nanoporous Membranes for High Heat Flux Thermal Management[END_REF]. The latent heat of vaporization is the dominant mode of heat transfer while the nanopore geometry generates the requisite capillary pressure to drive the liquid flow to the heat source. This will be studied numerically (to increase the fundamental understanding of the phenomena) and be used to inform detailed experiments and system level design. Therefore, various solids (Si, SiO2,...), gases (Ar, H2O, N2,..) and rarefaction levels will be studied numerically.

Method

In order to study the two-phase cooling system, we start with a simplified model of evaporation and condensation of a water layer system as shown in fig. 2. We use Molecular Dynamics to investigate different properties of the simulation such as the temperature profile, heat flux, velocity distribution, water molecule orientation (WMO) [START_REF] Kim | Molecular Models for Water Vapor Flows in Silica Nanopores[END_REF] and the density distribution.

The dimensions of the simulation model are Lx, Ly = 121 Å, Lz = 260 Å and Lpt = 200 Å. The temperature at the bottom and top walls are kept constant using a Nose-Hoover thermostat with T1=368K and T2=278K. Periodic boundary conditions are applied in x,y and z direction. The water molecules are modeled using the TIP4P/2005 model [START_REF] Orsi | Comparative assessment of the ELBA coarse-grained model for water[END_REF] and the interaction between the 8 layers of platinum atoms are modeled using harmonic springs [START_REF] Torri | Molecular dynamics study on ultrathin liquid water film sheared between platinum solid walls: Liquid structure and energy and momentum transfer[END_REF].

Results

The results obtained so far are the WMO and the density distribution. It is observed in fig. 3 that there exists a preferred water molecule orientation around 80°-120° and 40° near the bottom wall. A similar observation can be made near the upper wall. In the bulk no preferred WMO is observed. This could influence the liquid-vapor interface and evaporation.

The density distribution along the z-axis shown in fig. 4 indicates the high density in the walls and a decay near the liquid vapor interface.

The temperature profile, which is under investigation at the moment, will give us the opportunity to see possible temperature jumps near the solid-liquid and/or liquid/vapor interface and thereby provide us detailed information on the evaporation resistances.

Figure 1 :

 1 Figure 1: Nanopore evaporation

Figure 4 :

 4 Figure 4: Density distribution along the z-axis. Red lines indicate the walls

Figure 3 :

 3 Figure 3: WMO near the bottom wall. Red line: begin of the bottom wall. Right insert: definition of water molecule orientation (WMO).

Figure 2 :

 2 Figure 2: Simulation model for evaporation and condensation of a water layer

* Corresponding author

Acknowledgements

This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 643095.