A series of bidentate amidate ligands with variable groups R' and R" abbreviated by [R"(NO)R'] and adamantyl substituted tetradentate amidate ligands abbreviated by Ad[0₂N₂] were utilized as ancillaries for Ti, Zr, and Hf. Protonolysis routes into homoleptic amidate complexes, tris(amidate) mono(amido), bis(amidate) bis(amido), and bis(amidate) dibenzyl complexes are high yielding when performed with tetrakis(amido) and tetrabenzyl group 4 starting materials. Many of these complexes have been characterized in both the solid-state and in the solution phase, where in the latter case these complexes are fluxional and undergo exchange processes. Multiple geometric isomers are possible with the mixed N,0 chelate provided by the amidate ligands, and geometric isomerization of bis(amidate) bis(amido) complexes has been examined through X-ray crystallographic and density functional theory (DFT) calculations. Isomerization is dictated largely by the steric bulk present at the N of the amidate ligands, and is proposed to proceed through a K²-K¹-K² ligand isomerization mechanism, which is supported by crystallographic evidence of K¹-bound amidate ligands. The amidate ligand system binds to these metals in a largely electrostatic fashion, with poor orbital overlap, generating highly electrophilic metal centers. The bis(amidate) dibenzyl complexes of Zr and Hf are reactive towards insertion, abstraction, and protonolysis. Insertion of isocyanides into the Zr-C bonds of [DMP(NO) tBu]₂Zr(CH₂Ph₂ results in the formation of ƞ₂-iminoacyl complexes, which can either undergo thermally induced C=C coupling to generate an enediamido complex (aryl isocyanides), or rearrange to generate a bis(amidate) bis(vinylamido) complex (alkyl isocyanides). Benzyl abstraction to generate cationic Zr bis(amidate) benzyl complexes is also possible through reaction with [Ph₃C][B(C₆F₅)4] or B(C₆F₅)₃ Terminal imido complexes with novel pyramidal geometries are generated through protonolysis of bis(amidate) bis(amido) Ti and Zr complexes with primary aryl amines. DFT calculations demonstrate the existence of a Zr⁻₌N triple bond for these complexes. Dimeric imido complexes have been characterized in the solid state, but are not maintained in solution. Cycloaddition reactions of the terminal Zr imido complexes with C=0 bonds result in the formation of proposed oxo complexes and organic metathesis products. Catalytic aminoalkene cyclohydroamination has also been realized with these complexes, generating N-heterocyclic products. A series of kinetic and labeling studies support an imido-cycloaddition mechanism for catalytic cyclohydroamination of primary aminoalkenes with neutral bis(amidate) Ti and Zr precatalysts. The intermediate Ti imido complex, K²-[Dipp(NO)tBu-K¹_[DiPP(No) tBu]Ti=NCH₂CPh₂CH₂CH=CH₂(NHMe₂), has been isolated and characterized in the solid-state and in solution. Amine stabilized imido complexes of this type are invoked as the resting state for the catalytic reaction, and solution phase data support a chair-like geometry, where the alkene is coordinated to the metal center. A diastereoselectivity study supports this proposed solution structure. Eyring and Arrhenius parameters, as well as isolation of a 7-coordinate model imido complex, support a seven-coordinate transition state for the rate-determining metallacycle protonolysis reaction. In contrast, secondary aminoalkene hydroamination catalysis with cationic Zr benzyl complexes is proposed to proceed through a σ-bond insertion mechanism. Proton loss from cationic Zr amido complexes to generate imido species is proposed with primary aminoalkenes, and the resultant neutral imido complexes can catalyze the cyclization of these substrates by the aforementioned imido-cycloaddition mechanism. The ability of the amidate ligand system to promote both mechanisms is unique in the field of alkene hydroamination catalysis.

This thesis concerns the new amine-substituted cyclopentadiene and indene ligands C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H and C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H which can co-ordinate to a metal through all five carbon atoms of the five-membered ring (η(^5)) and/ or through the nitrogen (σ). Chapter 1 reviews the recent literature concerning Lewis-base functionalised cyclopentadienyl and indenyl ligands and their compounds with s-, p-, d- and f-block metals. Chapter 2 contains a brief review of possible synthetic routes to amine-substituted cyclopentadienyl and indenyl ligands with some examples from the recent literature, and a detailed account of the synthesis of C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H and C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H. The amino alcohol (^t)BuNH(CH(_2))(_3) OH was synthesised by the conjugate addition of (^t)BuNH(_2) to ethyl acrylate and reduction of the product ester (^t)BuNH(CH(_2))(_2)C0(_2)Et using LiAIH(_4). (^t)BuNH(CH(_2))(_3)OH was converted into (^t)BuNH(CH(_2))(_3)Br.HBr and (^t)BuNH(CH(_2)(_3)Cl.HCl by reaction with HBr or SOCI(_2). Reaction between (^t)BuNH(CH(_2))(_3)C1.HC1 and two equivalents of Na(C(_5)H(_5)) gave C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H in good yield. Treatment of (^1)BuNH(CH(_2))(_3)C1.HC1 with excess NaOH followed by reaction with Li(C(_9)H(_7)) gave C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H, also in good yield. Chapter 3 describes the synthesis of various main group and iron compounds of C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H and C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H. Lithium salts Li[C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H], Li[C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)]Li, Li[C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)H] and Li[C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)]Li were prepared for use as reactive intermediates and Li[C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H] was characterised as its THF-adduct by (^t)H NMR spectroscopy. The silyl derivatives (Me(_3)Si)C(_5)H(_4)(CH(_2))(_3)NH(^t)Bu and (Me(_3)Si)C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)SiMe(_3) were synthesised and characterised by NMR spectroscopy, and (Me(_3)Si)C(_9)H(_6)(CH(_6))(_3)N((^t)Bu)H and (Me(_3)Si)C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)(SiMe(_3)) were also synthesised. The anune-substituted ferrocene Fe{η(^5)-C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H}(_2) was synthesised and oxidised to the corresponding ferricenium ion which was isolated as its PF(_6)(^-) salt. Exploratory work was carried out into the preparation of heterobimetallic species by reaction between Fe{η(^5)-C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H}(_2) and MX(_2) (M = Co, Ni, X = CI, M = Mn, X = Br). The substituted bis(indenyl) iron(II) complex Fe{η(^5)-C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)H}(_2) was also synthesised. Chapter 4 is an account of the chemistry of {η(^5) :σ-C(_5)H(_4) (CH(_2))(_3)N(^t)Bu}Ti(NMe(-2))(_2) which was synthesised by an aminolysis reaction between C(_5)H(_5)(CH(_2))(_3)NH(^t)Bu and Ti(NMe(_2))(_4) Reaction between this compound and various weak acids gave a range of new compounds including{η(^5):σ-C(_5)H(_4)(CH(_2))(-3)N(^t)Bu} Ti(O(^t)Pr)(_2), {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu)(_2), {η(^5):σC, {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(C(_5)H(_5))(NMe(_2)) , {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(SnBu(_3))(_z) and the imido-bridged dimer [{η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(NHPh)](_2)(µ-NPh)2, the X-ray structure of which is reported. Chapter 5 describes the experimental procedures used, and chapter 6 gives lists of characterising data for each compound. Appendix A gives details of the methods used for magnetic susceptibility determinations; appendix B lists X-ray crystallographic data for [ {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(NHPh)](_2)(µ-NPh)(_2) and appendix C lists departmental colloquia attended.

A series of bidentate amidate ligands with variable groups R' and R" abbreviated by [R"(NO)R'] and adamantyl substituted tetradentate amidate ligands abbreviated by Ad[0₂N₂] were utilized as ancillaries for Ti, Zr, and Hf. Protonolysis routes into homoleptic amidate complexes, tris(amidate) mono(amido), bis(amidate) bis(amido), and bis(amidate) dibenzyl complexes are high yielding when performed with tetrakis(amido) and tetrabenzyl group 4 starting materials. Many of these complexes have been characterized in both the solid-state and in the solution phase, where in the latter case these complexes are fluxional and undergo exchange processes. Multiple geometric isomers are possible with the mixed N,0 chelate provided by the amidate ligands, and geometric isomerization of bis(amidate) bis(amido) complexes has been examined through X-ray crystallographic and density functional theory (DFT) calculations. Isomerization is dictated largely by the steric bulk present at the N of the amidate ligands, and is proposed to proceed through a K²-K¹-K² ligand isomerization mechanism, which is supported by crystallographic evidence of K¹-bound amidate ligands. The amidate ligand system binds to these metals in a largely electrostatic fashion, with poor orbital overlap, generating highly electrophilic metal centers. The bis(amidate) dibenzyl complexes of Zr and Hf are reactive towards insertion, abstraction, and protonolysis. Insertion of isocyanides into the Zr-C bonds of [DMP(NO) tBu]₂Zr(CH₂Ph₂ results in the formation of ƞ₂-iminoacyl complexes, which can either undergo thermally induced C=C coupling to generate an enediamido complex (aryl isocyanides), or rearrange to generate a bis(amidate) bis(vinylamido) complex (alkyl isocyanides). Benzyl abstraction to generate cationic Zr bis(amidate) benzyl complexes is also possible through reaction with [Ph₃C][B(C₆F₅)4] or B(C₆F₅)₃ Terminal imido complexes with novel pyramidal geometries are generated through protonolysis of bis(amidate) bis(amido) Ti and Zr complexes with primary aryl amines. DFT calculations demonstrate the existence of a Zr⁻₌N triple bond for these complexes. Dimeric imido complexes have been characterized in the solid state, but are not maintained in solution. Cycloaddition reactions of the terminal Zr imido complexes with C=0 bonds result in the formation of proposed oxo complexes and organic metathesis products. Catalytic aminoalkene cyclohydroamination has also been realized with these complexes, generating N-heterocyclic products. A series of kinetic and labeling studies support an imido-cycloaddition mechanism for catalytic cyclohydroamination of primary aminoalkenes with neutral bis(amidate) Ti and Zr precatalysts. The intermediate Ti imido complex, K²-[Dipp(NO)tBu-K¹_[DiPP(No) tBu]Ti=NCH₂CPh₂CH₂CH=CH₂(NHMe₂), has been isolated and characterized in the solid-state and in solution. Amine stabilized imido complexes of this type are invoked as the resting state for the catalytic reaction, and solution phase data support a chair-like geometry, where the alkene is coordinated to the metal center. A diastereoselectivity study supports this proposed solution structure. Eyring and Arrhenius parameters, as well as isolation of a 7-coordinate model imido complex, support a seven-coordinate transition state for the rate-determining metallacycle protonolysis reaction. In contrast, secondary aminoalkene hydroamination catalysis with cationic Zr benzyl complexes is proposed to proceed through a σ-bond insertion mechanism. Proton loss from cationic Zr amido complexes to generate imido species is proposed with primary aminoalkenes, and the resultant neutral imido complexes can catalyze the cyclization of these substrates by the aforementioned imido-cycloaddition mechanism. The ability of the amidate ligand system to promote both mechanisms is unique in the field of alkene hydroamination catalysis.

A series of bidentate amidate ligands with variable groups R' and R" abbreviated by [R"(NO)R'] and adamantyl substituted tetradentate amidate ligands abbreviated by Ad[0₂N₂] were utilized as ancillaries for Ti, Zr, and Hf. Protonolysis routes into homoleptic amidate complexes, tris(amidate) mono(amido), bis(amidate) bis(amido), and bis(amidate) dibenzyl complexes are high yielding when performed with tetrakis(amido) and tetrabenzyl group 4 starting materials. Many of these complexes have been characterized in both the solid-state and in the solution phase, where in the latter case these complexes are fluxional and undergo exchange processes. Multiple geometric isomers are possible with the mixed N,0 chelate provided by the amidate ligands, and geometric isomerization of bis(amidate) bis(amido) complexes has been examined through X-ray crystallographic and density functional theory (DFT) calculations. Isomerization is dictated largely by the steric bulk present at the N of the amidate ligands, and is proposed to proceed through a K²-K¹-K² ligand isomerization mechanism, which is supported by crystallographic evidence of K¹-bound amidate ligands. The amidate ligand system binds to these metals in a largely electrostatic fashion, with poor orbital overlap, generating highly electrophilic metal centers. The bis(amidate) dibenzyl complexes of Zr and Hf are reactive towards insertion, abstraction, and protonolysis. Insertion of isocyanides into the Zr-C bonds of [DMP(NO) tBu]₂Zr(CH₂Ph₂ results in the formation of ƞ₂-iminoacyl complexes, which can either undergo thermally induced C=C coupling to generate an enediamido complex (aryl isocyanides), or rearrange to generate a bis(amidate) bis(vinylamido) complex (alkyl isocyanides). Benzyl abstraction to generate cationic Zr bis(amidate) benzyl complexes is also possible through reaction with [Ph₃C][B(C₆F₅)4] or B(C₆F₅)₃ Terminal imido complexes with novel pyramidal geometries are generated through protonolysis of bis(amidate) bis(amido) Ti and Zr complexes with primary aryl amines. DFT calculations demonstrate the existence of a Zr⁻₌N triple bond for these complexes. Dimeric imido complexes have been characterized in the solid state, but are not maintained in solution. Cycloaddition reactions of the terminal Zr imido complexes with C=0 bonds result in the formation of proposed oxo complexes and organic metathesis products. Catalytic aminoalkene cyclohydroamination has also been realized with these complexes, generating N-heterocyclic products. A series of kinetic and labeling studies support an imido-cycloaddition mechanism for catalytic cyclohydroamination of primary aminoalkenes with neutral bis(amidate) Ti and Zr precatalysts. The intermediate Ti imido complex, K²-[Dipp(NO)tBu-K¹_[DiPP(No) tBu]Ti=NCH₂CPh₂CH₂CH=CH₂(NHMe₂), has been isolated and characterized in the solid-state and in solution. Amine stabilized imido complexes of this type are invoked as the resting state for the catalytic reaction, and solution phase data support a chair-like geometry, where the alkene is coordinated to the metal center. A diastereoselectivity study supports this proposed solution structure. Eyring and Arrhenius parameters, as well as isolation of a 7-coordinate model imido complex, support a seven-coordinate transition state for the rate-determining metallacycle protonolysis reaction. In contrast, secondary aminoalkene hydroamination catalysis with cationic Zr benzyl complexes is proposed to proceed through a σ-bond insertion mechanism. Proton loss from cationic Zr amido complexes to generate imido species is proposed with primary aminoalkenes, and the resultant neutral imido complexes can catalyze the cyclization of these substrates by the aforementioned imido-cycloaddition mechanism. The ability of the amidate ligand system to promote both mechanisms is unique in the field of alkene hydroamination catalysis. / Science, Faculty of / Chemistry, Department of / Graduate

Amine bis(phenolate) ligands synthesis can be easily prepared by the reaction of a substituted 2-(bromomethyl)phenol, a substituted phenol, potassium carbonate, triethylamine and the appropriate amine to form the desired compounds in high yields and purities. A series of amine bis(phenolate) ligand precursors with group 4 metals and aluminum complexes have been prepared, characterized by single-crystal X-ray diffraction, and tested for ring opening polymerisation of £`-caprolactone. Group 4 metals complexes which are shown to be active catalysts for the ROP of £`-caprolactone with excellent conversions and polydispersities. All aluminum compounds as four-coordinate aluminum methyl complexes show excellent catalytic activity toward the ring opening polymerization of £`-caprolactone in the presence of benzyl alcohol. And amine bis(phenolate)s ligand ([tert-ButylONO]2-) bond cleavage with zirconium and hafnium complexes that have been prepared, characterized by single-crystal X-ray diffraction. Another zirconium complexes of dianionic amine bis(phenolate) ligands have been synthesized, their X-ray structures solved, and their activity as 1-hexene polymerization catalysts study. Upon treatment with B(C6F5)3, a series of pentacoordinate [ONO]Zr(CH2Ph)2 complex, having no extra donor group, shows only poor activity as a polymerization catalyst. Final reaction of diamine-bis(phenol) ligands containing a mixture of [i-PropylONO]Ti(OiPr)2 in dry THF under RT without exclusion of air and moisture gives {[i-PropylONO]TiO}3 (characterised by X-ray crystallography) is hydrolysed with H2O.

The synthesis and electropositive metal (Y, Lu, La, Zr, Hf) chemistry of two rigid dianionic xanthene-based ligands, 4,5-bis(2,4,6-triisopropylanilido)- -2,7-di-tert-butyl-9,9-dimethylxanthene (XN2) and 4,5-bis(2,4,6-triisopropylphenylphosphido)- 2,7-di-tert-butyl-9,9-dimethylxanthene (XP2) have been explored. The reaction of the pro-ligand H2XN2 with [Y(CH2SiMe2R)3(THF)2] (R = Me or Ph) produced the monoalkyl yttrium complexes [(XN2)Y(CH2SiMe3)- (THF)].(O(SiMe3)2)x (3, x = 1-1.5) and [(XN2)Y(CH2SiMe2Ph)(THF)].(O- (SiMe3)2) (4). Neutral 3 reacted with excess AlMe3 to yield [(XN2)Y{(m- Me)2AlMe2}(THF)].O(SiMe3)2 (5.O(SiMe3)2), which is thermally robust, and transfer of the XN2 ligand to aluminum was not observed. However, [(XN2)- AlMe].(O(SiMe3)2)0.5 (6.(O(SiMe3)2)0.5) was synthesized via the reaction of H2XN2 with AlMe3. Compounds 3, 5 and 6 were characterized by X-ray crystallography, and neutral 3, while being poorly active for ethylene polymerization, was highly active for both intra- and inter-molecular hydroamination with a variety of substrates. The synthesis of the pro-ligand H2XP2 was achieved via reduction of 4,5-bis(2,4,6-triisopropylphenylchlorophosphino)-2,7-di-tert-butyl-9,9-dimethylxanthene (XP2Cl2; 7). Double deprotonation of H2XP2 (8) with excess KH yielded the potassium salt, [K2XP2(DME)2.5] (9), which when stirred in THF followed by recrystallization from hexanes, produced the tetrametallic complex, [K4(XP2)2(THF)4] (10) featuring a central K4P4 cage. The reaction of [K2XP2(DME)2.5] (9) with [YI3(THF)3.5] yielded a mixture of products including [(XP2)YI(THF)2] (11) and tris(2,4,6-triisopropylphenylphosphinidene) (P3Tripp3); pure 11 could be isolated in low yield by extraction with a minimum volume of hexanes or O(SiMe3)2. In the solid state, complex 11 reveals a face-capped trigonal bipyramidal geometry at yttrium, in which the xanthene backbone is planar and adopts a large angle (85 degrees) between the P(1)/C(4)/C(5)/P(2) and P(1)/Y/P(2) planes. Due to the successful synthesis and hydroamination catalysis achieved with the XN2 ligand in combination with yttrium, the chemistry of XN2 was further explored using both smaller (Lu) and larger (La) rare earth elements. The alkane elimination reaction of H2XN2 with [Lu(CH2SiMe3)3(THF)2], followed by crystallization from O(SiMe3)2, yielded [(XN2)Lu(CH2SiMe3)(THF)].(O- (SiMe3)2)1.5 (12.(O(SiMe3)2)1.5). By contrast, lanthanum complexes of the XN2 dianion were prepared by salt metathesis; treatment of H2XN2 with excess KH in DME produced the dipotassium salt, [K2(XN2)(DME)x] (2; x = 2-2.5), and subsequent reaction with [LaCl3(THF)3] afforded [{(XN2)LaCl- (THF)}x].(O(SiMe3)2)0.25x (13.(O(SiMe3)2)0.25x; x = 1 or 2) after crystallization from O(SiMe3)2. Compound 13.(O(SiMe3)2)0.25x reacted with two equivalents of LiCH2SiMe3, to form the dialkyl-`ate' complex, [Li(THF)x][(XN2)- La(CH2SiMe3)2].Toluene.LiCl (14.Toluene.LiCl; x = 3). Both 12 and 14 (x = 4) were structurally characterized by X-ray crystallography, and were evaluated as catalysts for intramolecular hydroamination. While compound 14 showed poor activity, the neutral lutetium alkyl complex, 12, is highly active for both intramolecular hydroamination and more challenging intermolecular hydroamination. Like the yttrium analogue, 3, reactions with unsymmetrical alkenes yielded Markovnikov products. Additionally, it is noteworthy that the activity of 12 surpassed that of 3 in the reaction of diphenylacetylene with 4-tert-butylbenzylamine. The reaction of H2XN2 with [Zr(NMe2)4], followed by crystallization from O(SiMe3)2, yielded [(XN2)Zr(NMe2)2].(O(SiMe3)2)0.5 (15.(O(SiMe3)2)0.5). The zirconium dimethyl complex [(XN2)ZrMe2] (16) was accessed via two routes; either by treatment of 15.(O(SiMe3)2)0.5 with excess AlMe3, or by reaction of 15.(O(SiMe3)2)0.5 with excess Me3SiCl, affording [(XN2)ZrCl2] (17), followed by the subsequent reaction of 17 with 2 equivalents of MeLi. The reaction of 16 with one equivalent of B(C6F5)3 or [CPh3][B(C6F5)4] yielded cationic [(XN2)- ZrMe][MeB(C6F5)3] (18) and [(XN2)ZrMe(arene)][B(C6F5)4] (19; arene = n6-benzene, n6-toluene or bromobenzene), respectively. Both 18 and 19 are active for ethylene polymerization under 1 atm of ethylene at 24 and 80 degree Celcius in toluene, with activities ranging from 23.5{883 kg/(mol.atm.h), yielding polymers with weight average molecular weights (Mw) of 71{88 kg/mol and polydispersities (Mw/Mn) of 3.94-4.67. / Thesis / Doctor of Philosophy (PhD) / Pincer ligands are defined as meridionally-coordinating tridentate ligands, and are typically mono-, di- or tri-anionic. This thesis is focused on the synthesis and reactivity of rigid dianionic pincer ligands with an NON- or POP-donor array, with particular emphasis on rare earth and group 4 transition metal complexes. This work explores the effect that these rigid ligands have on the reactivity of the resulting metal complexes and the thermal stability of the solid state structures. Both neutral and cationic mono alkyl complexes have been isolated, and several are highly active catalysts for intra- and intermolecular hydroamination or ethylene polymerization.

This thesis describes the synthesis, characterisation and reactivity of diamide-amine and bis(cyclopentadienyl) supported Group 4 hydrazido(2-) compounds towards unsaturated molecules. The mechanisms of these transformations are probed using a range of structural, kinetic and computational methods.

No description available.

Le concept de “paires frustrées de Lewis” (plus communément désignés par l’acronyme anglais FLPs) a suscité un vif intérêt depuis sa formulation en 2006. Initialement décrit à partir d’une phosphine encombrée comme base de Lewis et d’un borane comme acide de Lewis pour l’activation coopérative d’hydrogène sans métal, ce concept a été ensuite très largement développé en utilisant divers éléments du groupe principal (N/B, P/Al, N/Al …). Le concept a ensuite été étendu aux métaux de transitions pour pallier cette faiblesse: sont ainsi apparues les premières paires frustrées de Lewis organométalliques (OmFLPs). Dans le but de développer de telles OmFLPs, nous nous sommes intéressés à la synthèse de complexes cationiques titanocèniques et zirconocèniques en présence d’une amine. La première partie de cette thèse présente les travaux précédemment décrits sur les ligands azotés, en vue de synthétiser des complexes du groupe 4 N-fonctionnalisés. Une description plus détaillée du concept de FLP est ensuite réalisée, et un parallèle est fait avec des concepts connexes (coopérativité métal-ligand, systèmes ambiphiles). La seconde partie de ce manuscrit développe la synthèse de nouveaux ligands (aminomethyl)cyclopentadiènylure de potassium ainsi qu’une étude de leur coordination aux métaux du groupe 4. Cette étude a permis d’accéder à toute une série de nouveaux complexes dichlorotitanocènes et zirconocènes porteurs d’une fonction amine tertiaire encombrée (diisopropylaminyl et 2,2,6,6-tétraméthylpipéridine) à proximité du centre métallique. Ces travaux ont montré que l’amine ne se coordine pas audit centre métallique. Les métallocènes ainsi formés ont ensuite été transformés en cation afin de renforcer le caractère acidité de Lewis du centre métallique. Ces espèces ont montré une réactivité inattendue donnant lieu à des réarrangements par activation CH au voisinage de l’atome d’azote. Ces réarrangements ainsi que des études mécanistiques font l’objet du troisième chapitre. La quatrième partie de ce mémoire porte sur la synthèse de complexes phosphido- et amidotitanocènes cationiques. Ces complexes montrent une très bonne activité en catalyse d’hydrogénation de petites molécules dans des conditions relativement douces, vraisemblablement pour des raisons d’effets coopératifs entre le métal et le ligand. Dans une dernière partie, la synthèse de complexes titanocéniques cationiques portant une fonction iminophosphorane est développée, suivie d’une étude de réactivité de ces complexes en tant que paires frustrées de Lewis organométalliques. / In 2006, the concept of “frustrated Lewis pairs” (called FLPs) was introduced. The main characteristic of these compounds is their ability to activate cooperatively small molecules without the use of a metal (H2, CO2, alkene alkyne…). Initially based on P/B combination, the concept has been extended to several other main group elements (N/B, P/Al, N/Al …). Recently, FLPs have been extended to the transition metal realm. These organometallic FLPs (OmFLPs) are obviously non-metal free systems but they extend significantly the scope of FLP applications. Seeking to develop such systems, a research toward new omFLP combinations (N/Ti+, N/Zr+) has been initiated in our group, based on the synthesis of N-based titanocene and zirconocene complexes. The first part of this manuscript deals with a survey of the literature of such compounds, and a more detailed presentation of FLPs and related concepts (metal-ligand cooperativity, ambiphilic ligands) are also developed. In a second chapter, the synthesis of new N-based cyclopentadienyl ligands and their coordination to group 4 metals is presented. The formation of a cationic complex is then developed in a third part on selected titanocenes. In these complexes, the amine function undergoes CH activation by the cationic metal centre, leading to unexpected rearrangements. Investigations on their plausible mechanism are also presented. In a fourth part, the synthesis of new cationic phosphido- and amidotitanocenes, discovered in the course of our study on OmFLPs, is developed. The cationic amidotitanocenes are shown to be catalytically active towards hydrogenation of small molecules. Lastly, the potential of cationic titanocenyl iminophosphoranes as OmFLPs, was developed.

Title: Development of novel photoactive cationic zirconocene complexes Author: Bc. David Dunlop Department: Department of inorganic chemistry Supervisor: RNDr. Martin Lamač Ph.D. Advisor: prof. RNDr. Petr Štěpnička, Ph.D., DSc. Abstract: Environmental concerns have brought about an unprecedented demand for sustainable energy sources among which electromagnetic radiation, light, currently dominates. Development of novel light- harvesting compounds and materials is at the forefront of current science, as it is essential to further our technological progress. This thesis contributes to the field by development of novel photoactive cationic group 4 metallocene complexes stabilized by pendant imine and pyridinyl donor groups, or N,O-donor aromatic ligands, as crystalline [B(C6F5)4]− salts. The complexes are prepared either by protonation of the intramolecularly bound imine moiety by PhNMe2H[B(C6F5)4] or by chloride ligand abstraction, by Li[B(C6F5)4]·2.5Et2O or in situ generated Et3Si[B(C6F5)4]. Prepared compounds were characterized by NMR spectroscopy. Solid state structures of the compounds were determined by X-ray diffraction analysis. The cationic complexes of Zr and Hf exhibited significantly enhanced luminescence which originates from triplet ligand-to-metal (3 LMCT) excited states with lifetimes of up to...