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Gold Nanoclusters are of particular interest due to their many possible applications across a wide range of scientific fields. More specifically, nano-sized gold particles have potential to be used in drug delivery systems, cancer therapy and catalysis. This dissertation focuses on improving our understanding of ligated gold nanoclusters by examining the role of a variety of phosphine based ligands, novel methods to produce monodisperse solutions, and investigating the kinetics of water soluble ligated gold nanoclusters. The addition of ligands to solutions of Au have shown to produce small (< 20 Au atoms) clusters. All nanocluster solutions were prepared in a similar manner. Typically, a gold salt, either Chloro(triphenylphosphine) gold(I) (Au(PPh3)Cl), or Potassium gold (III) chloride (KAuCl4), were dissolved in various solvents. Next, an equal concentration of ligand was added to the solution and stirred until completely dissolved. Finally, all were reduced with 5X the concentration of borane-tert-butylamine (BTBC) after which were sonicated for ~20 minutes. The timing and method of adding the ligands and reducing agent varied depending on the solution and solubility of the ligands. Primarily we used Electrospray Ionization Mass Spectrometry (ESI-MS) and Ultraviolet – Visible Spectroscopy (UV-VIS) for the characterization of samples, however, occasionally Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD) and X-Ray Photoemission Spectroscopy (XPS) were used. The most recent research took advantage of the size selective nature of an alpha hemolysin (a-HL) nanopore to investigate the kinetics of thiol-ligated Au clusters ~2 nm in size. The relationship between ligand rigidity and solvent polarity and the size and dispersity of Au cluster suspensions was investigated. We observed the formation of stable monodisperse clusters with the shortest ligand, (L3), independent of solvent. With a longer flexible ligand, (L6), we observed primarily Au8-10 cores depending on the ratio of L6/PPh3. All other ligands yielded polydisperse distributions. These dispersions contained clusters with a nuclearity between 8 and 11, for example [Au10(PPh3)9]3+ in LBn and [Au8(PPh3)7]2+ in LBp, were observed in the initial stages, but they were not stable and precipitated out or plated the glass vial. We also observed that the polarity of the solvent did not play a significant role in the formation of MPC’s, however a correlation between the size of the solvent and MPC formation was observed. The growth and evolution of two unique gold structures was also observed via UV-Vis and ESI-MS. Solutions were prepared which contained Potassium gold (III) chloride and PPh2(CH2)3PPh2, i.e., 1,3-bis(diphenylphosphino)propane, denoted by L3, reduced with Borane tert-butylamine complex (BTBC) in a 1:1 diethyl ether:methanol mix, which yielded a stable [Au11(L3)5]+3. Starting with this known Au11 solution, the addition of Mn2+ has shown to lead to the formation of a stable diphosphine ligated Au8 and a new Au14 species. Additionally, we show that the co-reduction of NiCl2 and Au in the absence of the ligand (L3) does give us a simple method for the production of a monodisperse [Au9(PPh3)8]2+ cluster solution and via electroless deposition does give us a potential low temperature pathway to the formation of a AuNi nanoalloy particle.

Les amines, et plus généralement les dérivés organiques qui contiennent de l’azote, constituent la clef de voûte de bien des domaines de la chimie à haute valeur ajoutée. Ils ont toujours fait l’objet de nombreuses recherches dans différents domaines de la chimie organique et de la chimie fine telles que l’agrochimie et la pharmacie. Malgré tout, la synthèse de ces structures azotées constitue encore souvent défi important pour les équipes de recherche, qu’elles soient académiques ou industrielles. De nombreuses méthodes permettent la synthèse des amines dont la grande majorité est caractérisée par la présence d’un centre chiral en alpha ou en béta de l’atome d’azote. L’une des voies les plus largement explorées pour l’obtention des amines chirales depuis plus de cinquante ans demeure l’hydrogénation asymétrique de substrats azotés. Ce travail de recherche a été mené dans le cadre d’une collaboration avec la société HOLIS Technologies. Nous nous sommes concentrés sur la mise au point d’outils catalytiques de synthèse d’amines chirales primaires et plus précisément sur des systèmes homogènes mettant en œuvre des métaux de transition pour accéder à des réactions d’hydrogénation énantiosélective. Nous nous sommes intéressés à la synthèse de trois amines chirales cibles en chimie pharmaceutique, étayée par l’étude de molécules modèles analogues. Nous avons étudié l’hydrogénation de substrats prochiraux azotés de type oxime, imine ou énamine conduisant, en une ou deux étapes, à l’amine primaire chirale visée. Dans le premier chapitre, notre étude a porté sur la synthèse et la caractérisation fine de chacun des substrats et de leurs amines chirales correspondantes. La RMN 15N étudiée sur ces molécules a permis de constituer un outil d’analyse complémentaire dans l’élucidation de ces structures. Dans le deuxième chapitre nous nous sommes attachés à développer un outil de synthèse catalytique avec pour objectif l’hydrogénation asymétrique pour les molécules modèles comme pour les molécules complexes de chacun des trois projets. Le troisième chapitre est dédié à la compréhension fine du cycle catalytique que nous avons entamée grâce à des analyses RMN multinoyaux (essentiellement 103Rh et 31P) et à des calculs quantiques conduits sur les complexes cationiques du rhodium qui se sont révélés actifs. La synthèse globale de ces résultats nous amène à avoir la capacité de choisir le meilleur substrat (imine, énamine, oxime) et le système catalytique associé pour son hydrogénation, afin de répondre au besoin industriel précis de synthèse d’une amine primaire chirale donnée. / Amines, and more generally, nitrogen-containing compounds are key building blocks in the field of fine chemicals, especially agrochemistry and pharmaceuticals. Synthesis of these nitrogen-containing compounds still is a frequent challenge to academic as well as industrial research teams. Several methods are available for the synthesis of amines containing an alpha or beta chiral center and for more than fifty years, one of the most widely investigated methods is the asymmetric hydrogenation of unsaturated substrates. Our research in this field has lead to an industrial partnership with the HOLIS Technologies company. We focus on the development of catalytic tools in order to synthesize chiral primary amines and more precisely, homogeneous catalysis with transition metals to obtain enantioselective hydrogenation. We got involved with the synthesis of three primary chiral amines well known as key targets in the pharmaceutical industry, with the study of analogous models conducted in parallel. We have studied the hydrogenation of prochiral substrates such as enamines, imines, and oximes leading in one or two steps to the desired primary chiral amine. In the first chapter, synthesis and characterization of substrates and chiral amines are described. Use of 15N NMR on these nitrogen-containing molecules allows us to establish a complementary tool for the structure elucidation. The second chapter is dedicated to the optimization of a catalyst system for the asymmetric hydrogenation of these molecules. The third chapter contains the initial studies into the intricate details of the catalytic cycle with the use of multinuclear NMR analysis (especially 103Rh and 31P) and DFT calculations on rhodium cationic complexes. An overview of these results gives us insight into the choice of the best substrate (imine, enamine, oxime) and the optimal catalyst system for the hydrogenation with the goal of addressing the industrial need of a given chiral primary amine.

Les cyclodextrines (CDs) sont des oligosaccharides cycliques constituées de monomères D-(+)-glucopyranose liés entre eux par des liaisons glycosidiques α-(1→4). Les plus utilisées sont celles qui comportent six, sept ou huit unités glucose, et sont appelées α-CD, β-CD et γ-CD, respectivement. Grâce à leur structure "cage", les cyclodextrines sont capables de former des complexes d'inclusion avec diverses molécules, ouvrant ainsi la voie à des applications dans de nombreux domaines de la chimie. Un des développements les plus récents, à l’origine des travaux présentés dans cette thèse, concerne l'élaboration de molécules associant de manière covalente une cyclodextrine et un métal de transition,composés particulièrement adaptés à l'étude de réactions catalytiques confinées et/ou fonctionnant en mode supramoléculaire.La première partie de ce mémoire est une mise au point donnant un aperçu du rôle croissant joué en chimie des métaux de transition par des ligands hybrides associant des centres donneurs et une entité cavitale.Les chapitres suivants sont consacrés à la synthèse de deux ligands phosphorés originaux construits sur une plateforme β-CD, ainsi qu’à l’étude de leurs propriétés complexantes et catalytiques. Le premier, WIDEPHOS, est une β-CD méthylée qui intègre deux unités phenylphosphinidène "PPh" pontant chacune deux unités glucose adjacentes. Dans cette diphosphine qui est conçue comme un chélateur à très grand angle de chélation, les doublets libres des atomes de phosphore pointent vers l’intérieur de la plateforme CD. En présence d'entités MX2 "carré-plan" (M = Pd, Pt,Rh), WIDEPHOS forme des complexes chélate caractérisés par un angle P-M-P proche de 160º, autrement dit conduit à des complexes de stéréochimie trans "imparfaite". Cette dernière est à l’origine d'un mouvement de balancier du ligand autour du métal, l’oschélation, un mouvement qui permet à chacun des atomes de phosphore d’optimiser, à tour de rôle, la liaison qu’il forme avec le métal complexé. Une autre propriété remarquable de WIDEPHOS concerne sa propension à former des espèces dinucléaires dans lesquelles les deux centres métalliques sont confinés dans l’espace cavital. Les contraintes induites par la formation de tels complexes sont manifestes au niveau de l’angle d’inclinaison τ de l’un des atomes de phosphore ainsi que par l’apparition d’un mouvement d’ "oschélation" d’un fragment P,O constitutif de la CD. / Cyclodextrins (CDs) are cyclic oligosaccharides of various sizes containing several α-(1→4)-linked D-(+)- glucopyranose units. The commercially available ones comprise six, seven or eight glucose units, named respectively α-CD, β-CD and γ-CD. Their truncated cone-like and well-defined cavity are particularly attractive for the encapsulation of a variety of substrates. As such, they found numerous applications in many areas of chemistry. A recent development, from which the present work is inspired, consisted in covalently linking transition metals to CD cavities in order to perform and study catalytic reactions in a confined environment featuring steric repulsive or attractive noncovalent interactions with the substrate or/and the metal coordination sphere.The first part of this thesis focuses on reviewing transition metal-based cavitands, for which the first and second metal coordination spheres are controlled by their cavity-shaped ligand. The following chapters are concerned with the synthesis, coordination and catalytic properties of two new phosphane ligands built on a large β-CD scaffold. The first one, named WIDEPHOS, is a diphosphine having two phenylphosphinidene "PPh" units capping adjacent glucose units on a methylated β-CD. This ligand features two phosphorus lone pairs pointing to the cavity interior but not aligned. These geometrical features, combined with the large distance separating the two phosphorus atoms, promote the formation of "imperfect" trans-chelate complexes in which the metal centre swings about the ligand. This unprecedented molecular movement, christened "oschelation", allows each phosphorus atom to form an optimal bond in turn with the coordinated d8 and d10 transition metal ions. Further studies on WIDEPHOS proved that it is better suited for coordinating dinuclear fragments within the confinement of the large β-CD cavity. Severe steric constrains on the metal first sphere of coordination result in the formation of single μ-chlorido bridged dinuclear species. In this new type of square planar complexes, non-optimal orbital overlapping measured by the so-called tilt angle was also found to take place for one of the phosphorus atom together with an "oschelation" movement involving non identical donor atoms, namely a phosphorus and an oxygen atom. Static gold(I) dinuclear complexes displaying similar imperfect orbital overlapping for one of the phosphorus atom were also prepared.

Le but de ce travail de thèse était de développer de nouvelles familles de ligands polyfonctionnels pour étudier, dans un premier temps, leur chimie de coordination vis-à-vis de métaux de transition et, dans un second temps, en fonction des espèces formées, leurs propriétés physiques (magnétiques par exemple) et/ou catalytiques. L’évaluation de leur potentiel pour la formation de nouveaux matériaux ou la fonctionnalisation de supports métalliques faisait également partie intégrante des objectifs de cette thèse. De ce fait, chaque ligand a été fonctionnalisé avec des groupements adaptés à l’ancrage sur surfaces, comme des fonctions zwitterioniques ou des thio-éthers. / The aim of this thesis was to develop new families of polyfunctional ligands to study their coordination chemistry towards transition metals and, depending on the products formed, to investigate their physical (e.g. magnetic) and / or catalytic properties. The evaluation of their potential for the formation of new materials as well as for the functionalization of metal surfaces was also part of the objective of this thesis. Therefore, each ligand has been functionalized with groups suitable for the anchoring on metallic surfaces, such as zwitterionic or thioethers moieties.

Condensation of Ph2PCH2OH with a range of polyaromatic substituted secondary amines afforded a new set of 'hybrid' phosphine ligands of the type {RCH2N(CH2PPh2)CH2}2 and RCH2N(CH2PPh2)CH2CH3 (R = various planar aromatic groups). The coordination chemistry of these new mono and bidentate ligands towards a range of transition metal centres including Mo(0), Au(I), Rh(I), Ni(II), Pd(II), Pt(II) and Ru(II) was investigated. Ditertiary phosphines of the form {RCH2N(CH2PPh2)CH2}2 were found to be capable of bridging two transition metal centres in addition to forming rare examples of nine-membered cis- and trans- chelate complexes. Single crystal X-ray analysis of these coordination compounds revealed several types of inter- and intramolecular packing interactions (including a C-H···Pt interaction and slipped intermolecular π····π stacking), and also confirmed the rare trans-diphosphine coordination mode. Fluorescent emission measurements have been undertaken on these new tertiary phosphines and their coordination compounds, and these luminescent properties are discussed. A preliminary investigation into the chemosensory behaviour of selected compounds has been undertaken. Using RPCH2OH (RP = Ph2P, Cy2P or AdP = 1,3,5,7,-tetramethyl-2,4,8-trioxa-6- phosphaadamantane) as a versatile precursor, a range of ferrocenyl (Fc) tertiary phosphines have been prepared from a selection of primary and secondary amines. The coordination chemistry of these new mono and bidentate ligands towards several transition metal centres including Cr(0), Mo(0), Au(I), Rh(I), Ru(II), Pd(II) and Pt(II) was investigated. In particular, the previous chemistry was expanded to prepare several new diferrocenyl phosphines of the form {FcCH2N(CH2PR)CH2}2. In a similar manner to their polyaromatic counterparts, these ditertiary phosphines were found to be capable of coordination through both bridging and cis- / trans-chelating modes. Notably, single crystal X-ray analysis was used to confirm the formation of an extremely rare example of a dimeric trans, trans-[Rh(CO)Cl{phosphine}2]2 complex; thought to be the first crystallographically characterised metallacycle containing an Rh2Fe4 arrangement of metal centres. In addition to this {FcCH2N(CH2PR)CH2}2 chemistry, a rare example of a triferrocenyl ditertiary ii phosphine, {FcCH2N(CH2PPh2)CH2}2Fc, was prepared, as well as a macrocyclic ditertiary ferrocenyl phosphine, C10H8Fe(CH2N(CH2PPh2)CH2)2CH2. The coordination chemistry of {FcCH2N(CH2PPh2)CH2}2Fc led to the formation of two unusual examples of pentametallic diphosphine coordination complexes with a Fe3Au2 and Fe3Ru2 arrangement of metal centres. The development of a new phosphinoamine, (Ph2P)2NCH2Fc, and a new ferrocenyl iminophosphine, Ph2PCH(Ph)CH2C(H)NCH2Fc, are also discussed, in addition to a brief investigation of their coordination chemistry. Electrochemical measurements have also been undertaken on these ferrocenyl ligands and their respective coordination compounds (when purity, yield and stability would allow), and their redox chemistry discussed. A series of novel phosphorus(III) containing ligands of the forms (R)N(CH2PPh2)2 and (R)NHCOCH2N(CH2PPh2)2 (R = functionalised planar aromatic or ferrocenyl group) have been prepared. The phosphines were found to readily coordinate several transition metals including Pt(II), Pd(II) and Ru(II) to form a series of new cis- chelate and bridged bimetallic complexes. Analysis by single crystal X-ray diffraction revealed several types of inter- and intramolecular hydrogen bonding within the molecular structures of the phosphines and their coordination compounds, including the formation of several intermolecular 1D chains and the presence of an intramolecular N-H···N bond, which forces a 'scorpion-like' conformation.

There is considerable current interest in the design and synthesis of new phosphorus ligands and their transition metal complexes in view of their potential applications in homogeneous catalysis. The present study is concerned with the synthesis of new chiral and achiral “ diphosphazanes”, which constitute a class of versatile short-bite bidentate phosphine ligands, and studying their reactivity towards late transition metals (Ag, Pd and Ru). Symmetrical diphosphazane ligands, MeN{P(OR)2}2 (R = (1R, 2S, 5R)-menthyl) and MeN{P(SR)2}2, (R = C6H5) and unsymmetrical diphosphazane ligands, Ph2PN(Pri)PPhY, (Y =OC6H3Me2-2,6 or NMePh) have been synthesized and structurally characterized. The reactivity of these ligands towards the transition metal precursors viz., [PdCl2(COD)] and [CpRu(PPh3)2Cl] has been investigated. The reaction of [Ru(bipy)2Cl2] with the diphosphazane, PriN(PPh2)2 in the presence of AgOTf to synthesize [Ru(bipy)2{PriN(PPh2)2}2]OTf led to an unexpected entry into the Ag(I) chemistry of this ligand. By optimizing the reaction conditions, several mononuclear, dinuclear and trinuclear complexes such as [Ag(K2-PriN(PPh2)2)2]X, [Ag(µ-PriN(PPh2)2)X]2 and [Ag3(µ-(Cl)2(µ-PriN(PPh2)2)3]X (X = NO3, OTf or PF6) have been synthesized. A polymeric complex, [Ag2(µ-PriN(PPh2)2)( µ-NO3)2]n in which the ligand adopts a unique ‘Cs’ geometry has also beenstructurally characterized. This polymeric complex is used to synthesize a helical polymer,[Ag2{µ-PriN(PPh2)2}(DABCO)(NO3)2]n and π- π stacked supramolecular assemblies such as [Ag2(NO3)2(µ-Ph2PN(Pri)PPh2)(2,2'-bipy)2] and [Ag2{µ-PriN(PPh2)2}(1,10-phen)2](NO3)2]. The reaction of a sterically bulky diphosphazane ligand, EtN{P(OC6H3(Pri)2-2,6)2}2 (L) with[(η3-1-R,R’-C3H3)Pd(µ-Cl)]2 in the presence of NH4PF6 gives the cationic complex, [(η 3-1-R,R’-C3H3)Pd(L)]PF6 (R = H; R’= H or Me) as the sole product. In the absence of NH4PF6, theinitially formed cationic complex, [(η 3-C3H5)Pd(L)]PF6 is transformed into a mixture of chlorobridged complexes over a period of 96 h. An octa-palladium complex [(η3-C3H5)(2-Cl- η3-C3H4)Pd4(µ-Cl)4(µ-L)]2 is formed as a result of nucleophilic substitution by a chloride ligand at the central allyl carbon atom. The reaction of L with [(η3-C3H5)Pd(µ-Cl)]2 in the presence of K2CO3 yields a dinuclear complex, [(η3-C3H5)Pd2(µ-L)Cl] containing a coordinatively unsaturated T-shaped palladium center. This complex exhibits high catalytic activity and large“turn-over numbers” in the catalytic hydrophenylation of norbornene. Reactions of diphosphazanes with cyclometalated palladium complexes of the general formula [Pd( k2-(C,N)-Me2NCHMe(C6H4))(solvent)2]PF6 derived from a chiral amine, (S)-N,N-dimethyl-1-phenethylamine give chelate complexes of the type [Pd{ k2-(C,N)-Me2NCHMe(C6H4)}(LL)] PF6, (L-L = diphosphazane). Chiral racemic diphosphazanes give a mixture of diastereomeric(S,R and S,S) complexes which could not be separated. These cyclometalated complexes show moderate catalytic activity in C−C bond forming reactions (hydrophenylation /Suzuki coupling).

La synthèse de phosphines secondaires borane dérivées d’aminoacides ou de dipeptides, et leur application pour la préparation de ligands ou le greffage du fullerène, est décrite. Elle se fait sans racémisation avec des rendements atteignant 98%, par alkylation de phosphines borane primaires avec un dérivé γ-iodo aminoacide, dans les conditions de transfert de phase. Les diphosphines tertiaires dérivées d’aminoacides, obtenues après une seconde alkylation avec des rendements atteignant 70%, sont parmi les premiers exemples de diphosphines greffées par une liaison P-C sur la chaine latérale d’un aminoacide. Les mono et diphosphines dérivées d’aminoacides ont été testées en catalyse d’allylation ou d’hydrogénation asymétriques catalysées par des complexes de palladium ou de rhodium. D’un autre côté, un complexe de cis platine a été préparé à partir d'une diphosphine dérivée d'un aminoester. Ses propriétés cytotoxiques ont été testées sur des lignées cellulaires ovariennes cancéreuses A2780. Dans une seconde partie les phosphines secondaires borane d’aminoacides et de peptides ont été utilisées pour le greffage du fullerène, par hydrophosphination en transfert de phase. L’étude électrochimique du dérivé fullerène d’aminoester de benzyle, a permis d’établir que ce composé se décomposait par électrolyse, avec coupure de la liaison P-C, pour libérer le fullerène et la phosphine secondaire borane aminoester. Ces travaux ouvrent de nouvelles perspectives pour la chimie des dérivés phosphines ou fullerène d'aminoacides et de peptides. / The synthesis of secondary phosphine borane amino acids or dipeptides and their applications for the preparation of chiral ligands or for the grafting of fullerene, is described. These compounds were synthesized in good yield (up to 98%) without racemization. The principle of the synthesis is based on the alkylation of primary phosphine borane with a γ-iodo amino acid using phase transfer conditions. Tertiary diphosphine amino acids are obtained with 70% yield after a second alkylation. These compounds are one of the first examples of diphosphine grafted with a P-C bond on the side chain of amino acid. First of all, mono and diphosphine amino acid derivatives were used in asymmetric allylic substitution with palladium precursor or in asymmetric hydrogenation with rhodium precursor. In another hand, a cis platinum complex was synthesized with 60% yield from the diphosphine amino acid derivative. The cytotoxic properties of this complex were tested against human ovarian carcinogenic cell lines A2780. In the second part, the secondary phosphine borane amino acids and peptides have been used for grafting fullerene C60 by hydrophosphination using phase transfer conditions. The electrochemical study of the fullerene amino benzyl ester derivative has shown the cleavage of the P-C60 bond by electrolysis, affording the free fullerene and the secondary phosphine borane amino ester moiety. This work opens new perspectives for the chemistry of fullerene and phosphine derivatives of amino acids and peptides.

Dans la première partie de ce travail, nous avons réalisé une étude préliminaire qui avait pour objectif d’étendre la série de complexes dinucléaires du fer [Fe2(CO)4(k2-P2N2)(μ-dithiolate)], comprenant des ligands diphosphine de type P2N2, à des complexes possédant un pont azadithiolate en vue d’étudier leur comportement en milieu acide et le rôle des différentes bases présentes dans la seconde sphère de coordination de ces composés. Les nouveaux complexes [Fe2(CO)6(k2-PPh2NR2)(μ-adtBn)] (R = Ph, Bn)) ont été obtenus par réaction entre le précurseur [Fe2(CO)6(μ-adtBn)] et les diphosphines cycliques PPh2NR2 (avec R = Ph, Bn). Ces complexes ont été caractérisés spectroscopiquement et structuralement. Nous avons aussi montré que les modes de coordination de l’anion (tcnsR)-, dans l’ensemble des complexes sont très différents et affectent, par conséquent, les réseaux cristallins d’une manière très importante. Ceci permet de dire que la longueur de la chaine alkyl de l’anion (tcnsR)- ne devrait pas être le seul paramètre structural affectant les températures de transition. Le type de groupement CN (N3, N4, N5 ou N6) intervenant dans la coordination devrait alors jouer un rôle important dans l’empilement des entités moléculaires dans le réseau cristallin et par conséquent, les interactions intermoléculaires qui sont à l’origine des caractéristiques de la transition de spin (température de transition, coopérativité,…), devraient être affectées par le mode de coordination de l’anion. Dans la seconde partie, nous avons réalisé la synthèse de notre dipolarophile à partir de la sérine et la préparation des dipôles (oxydes de nitriles). La condensation de ces derniers avec la dehydroalanine nous a permis l’obtention de nouveaux α-aminoesters isoxazoliniques. Ces nouveaux α-aminoesters isoxazoliniques ont été obtenus d’une façon très accessible, et dans des conditions douces par la réaction de cycloaddition 1,3-dipolaire. Les résultats obtenus confirment l’utilité de cette réaction comme étant une voie très efficace pour former des nouveaux isoxazolines avec des bons rendements. / In the first part of this work, we realised a preliminary study to extend the series of dinuclear iron complexes [ Fe2(CO)4 (k2-P2N2) (μ-dithiolate)], including diphosphine ligands type P2N2, to complexes having an azadithiolate bridge, in order to study their behavior in acid medium and the role of different bases present in the second coordination sphere of these compounds. The new complexes [Fe2 (CO) 6 (k2-PPh2NR2) (μ -adtBn)] (R = Ph, Bn)) were obtained by reaction between the precursor [Fe2(CO)6(μ -adtBn)] and the cyclic diphosphines PPh 2NR2 (with R = Ph, Bn). These complexes have been spectroscopically and structurally characterized. We have also showed that the anion coordination modes (tcnsR)– in all these complexes are very different and affect, consequently, crystal lattices in a very important way. This suggests that the length of the alkyl chain of the anion (tcnsR)- should not be the only structural parameter affecting transition temperatures. The type of CN grouping (N3, N4, N5 or N6) involved in the coordination should then play an important role in the stacking of molecular entities in the crystal lattice as a result the intermolecular interaction, which are the origin of the spin transition characteristics (transition temperature, cooperativeness, ...), should be affected by the coordination mode of the anion.In the second part, we have realized the synthesis of our dipolarophile from serine and the preparation of dipoles (nitrile oxides). Their condensations with dehydroalanine allowed us to newly obtain isoxazolinic α-aminoesters. These novel isoxazolinic α-aminoesters were obtained in an accessible method, and under mild conditions by the 1,3-dipolar cycloaddition reaction. The obtained results prove the usefulness of this reaction as being a very efficient way to form new isoxazolines with good yields.