No description available.

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.

Plusieurs nouveaux complexes pinceurs de cobalt et de nickel ont été préparés avec le ligand pinceur de type POCOP : 2,6-(i-Pr2PO)2C6H4. Dans le cas du cobalt, une nouvelle voie de synthèse a été développée. Contrairement au cas du nickel, il s’agit ici de cobalt au degré d’oxydation +III. Les composés obtenus sont paramagnétiques. En outre, le dérivé bromé est instable à la lumière et se décompose en perdant un brome pour former le complexe pinceur de Co(II). La réactivité de ces complexes a été étudiée. Pour ce qui est du nickel, la catalyse de l’hydroamination a été élargie aux dérivés de l’acrylonitrile et aux amines aromatiques. En outre, la réaction d’hydroaryloxylation a été étudiée dans les mêmes conditions. Enfin, avec le 4-cyanostyrène et le cinnamonitrile, la formation d’amidines a été observée. Un complexe pinceur portant cette amidine a été isolé. Enfin, le cation réagit avec des anions fortement coordonnants tels le cyanure ou l’isocyanate. En outre, l’anion triflate peut être déplacé par l’eau, l’acrylonitrile et ses dérivés. Enfin, une réactivité particulière a été observée avec la morpholine, l’acétone et un mélange 1:1 aniline/triéthylamine. / A large variety of new POCOP pincer type complexes of cobalt and nickel have been prepared. All those complexes are based on the following POCOP pincer type ligand: 2,6-(i-Pr2PO)2C6H4 In the case of cobalt, a new synthetic pathway has been developped. Unlike nickel, complexes containing cobalt in the +III oxidation state are obtained, the mechanism of their formation remains unknown. These complexes are paramagnetic. The dibromo derivative is light-sensitive, decomposing by losing a bromine to form the Co(II) pincer complex. The reactivity of those complexes has been studied. Concerning nickel, the catalyzed hydroamination has been extended to the derivates of acrylonitrile, crotonitrile and methacrylonitrile and to aromatic amines. Moreover, hydroaryloxylation reaction has been studied under the same conditions. Finally, amidines formation was obtained with 4-cyanostyrene and with cinnamonitrile. A pincer complex bearing this amidine moiety has been isolated. The cationic complex reacts with strong coordinating anions like cyanide and isocyanate. Moreover, the triflate anion is displaced by water, acrylonitrile and acrylonitrile derivates. Finally, a particular reactivity has been observed with morpholine, acetone and a 1:1 mixture of aniline and triethylamine.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal.

Plusieurs nouveaux complexes pinceurs de cobalt et de nickel ont été préparés avec le ligand pinceur de type POCOP : 2,6-(i-Pr2PO)2C6H4. Dans le cas du cobalt, une nouvelle voie de synthèse a été développée. Contrairement au cas du nickel, il s’agit ici de cobalt au degré d’oxydation +III. Les composés obtenus sont paramagnétiques. En outre, le dérivé bromé est instable à la lumière et se décompose en perdant un brome pour former le complexe pinceur de Co(II). La réactivité de ces complexes a été étudiée. Pour ce qui est du nickel, la catalyse de l’hydroamination a été élargie aux dérivés de l’acrylonitrile et aux amines aromatiques. En outre, la réaction d’hydroaryloxylation a été étudiée dans les mêmes conditions. Enfin, avec le 4-cyanostyrène et le cinnamonitrile, la formation d’amidines a été observée. Un complexe pinceur portant cette amidine a été isolé. Enfin, le cation réagit avec des anions fortement coordonnants tels le cyanure ou l’isocyanate. En outre, l’anion triflate peut être déplacé par l’eau, l’acrylonitrile et ses dérivés. Enfin, une réactivité particulière a été observée avec la morpholine, l’acétone et un mélange 1:1 aniline/triéthylamine. / A large variety of new POCOP pincer type complexes of cobalt and nickel have been prepared. All those complexes are based on the following POCOP pincer type ligand: 2,6-(i-Pr2PO)2C6H4 In the case of cobalt, a new synthetic pathway has been developped. Unlike nickel, complexes containing cobalt in the +III oxidation state are obtained, the mechanism of their formation remains unknown. These complexes are paramagnetic. The dibromo derivative is light-sensitive, decomposing by losing a bromine to form the Co(II) pincer complex. The reactivity of those complexes has been studied. Concerning nickel, the catalyzed hydroamination has been extended to the derivates of acrylonitrile, crotonitrile and methacrylonitrile and to aromatic amines. Moreover, hydroaryloxylation reaction has been studied under the same conditions. Finally, amidines formation was obtained with 4-cyanostyrene and with cinnamonitrile. A pincer complex bearing this amidine moiety has been isolated. The cationic complex reacts with strong coordinating anions like cyanide and isocyanate. Moreover, the triflate anion is displaced by water, acrylonitrile and acrylonitrile derivates. Finally, a particular reactivity has been observed with morpholine, acetone and a 1:1 mixture of aniline and triethylamine.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

L'addition catalysée des amines ou phosphines sur des substrats insaturés (alcènes, alcynes ou allènes) constitue une méthode efficace pour la production d’amines et phosphines à hautes valeurs ajoutées. Pour ces réactions, les complexes hétéroleptiques des métaux alcalino-terreux ont émergé comme des précatalyseurs effi caces. Cette thèse décrit la synthèse de complexes des alcalino-terreux supportés par des ligands aminoalcoolates fluorés de type [{RO}AeN(SiMe2H)2] ({RO} = aminoalcoolate fluoré; Ae = Ca, Sr). Des études par diffraction de rayons X montrent que ces complexes utilisent des interactions Ae···F–C and β-Si–H···Ae pour être cinétiquement inertes. Étonnamment, la somme de ces interactions non-covalentes dites secondaires est prédominante par rapport à la coordination d'éthers sur le centre métallique. En outre, les ligands aminoalcoolates fluorés ont été utilisés pour préparer de rares exemples de complexes Ae hétéroleptiques impliquant la coordination intramoléculaire de donneurs d'électrons π (i.e. alcènes et alcynes). Ainsi, pour la première fois, des complexes Ae stabilisés par des combinaisons d’interactions Ae···Cπ, Ae···F−C et β-Si−H···Ae ont été synthétisés. La nature de ces interactions a été sondée par des moyens spectroscopiques, cristallographiques et calculatoires (DFT). En revanche, nos efforts pour obtenir des complexes Ca–aryles ont conduit à la formation de complexes trinucléaires originaux présentant des interactions secondaires β-Si-H···Ca extrêmement fortes. Certains de ces complexes de calcium ont ensuite été testés en catalyse d’hydrophosphination du styrène avec la diphénylphosphine. Ils ont démontré des activités remarquables (TOF ≈ 50 h−1) en conditions douces, ainsi qu’une régiosélectivité de 100% vers la formation du produit d'addition anti-Markovnikov. En collaboration avec le Pr. M. Etienne et le Dr C. Dinoi du Laboratoire de Chimie de Coordination (Toulouse), un précatalyseur hétéroleptique de calcium supporté par un ligand tris(indazolyl)borate fluoré a été utilisé pour l’hydroamination intramoléculaire du 2,2-diméthylpent-4-en-1-amine, et a fait preuve d’une activité catalytique parmi les plus élevées à ce jour. / The catalysed additions of amines or phosphines across unsaturated substrates (alkenes, alkynes or allenes) constitute atom-efficient routes for the production of valuable fine chemicals such as amines and phosphines. For these reactions, heteroleptic alkaline-earth complexes have emerged as promising precatalysts. This PhD thesis describes the synthesis and characterisation of a series of alkaline-earth complexes of type [{RO}AeN(SiMe2H)2] supported by fluorinated aminoalkoxides ({RO} = fluorinated aminoalkoxide; Ae = Ca, Sr ). X-ray diffraction studies show that these complexes heavily involve Ae···F–C and β-Si–H···Ae secondary interactions to achieve kinetic stabilisation. Remarkably, these so-called secondary, non-covalent interactions can be more beneficial towards the stabilisation of the metallic species than the coordination of ethers onto the metal centre. Furthermore, fluorinated aminoalkoxo ligands were used to prepare rare examples of Ae heteroleptic complexes featuring intramolecular coordination from π donors (i.e. alkenes and alkynes). For the first time, Ae complexes stabilised by a combination of Ae···Cπ, Ae···F–C and β-Si–H···Ae interactions were described. The structural and electronic features of these unique complexes were probed by crystallographic, spectroscopic and computational (DFT) methods. The utilisation of aryl-containing ligands resulted in the formation of trinuclear complexes featuring a unique pattern of strong β-Si–H···Ca agostic interactions. Some of these calcium heteroleptic complexes were tested in the hydrophosphination of styrene and HPPh2. They displayed high activities (TOF ≈ 50 h–1) under mild conditions with 100% regioselectivity towards the anti-Markovnikov addition product. In a collaboration with Prof. M. Etienne and Dr. C. Dinoi from the Laboratoire de Chimie de Coordination (Toulouse), a heteroleptic calcium complex supported by a fluorinated tris(indazolyl)borate was used in the intramolecular hydroamination of 2,2-dimethylpent-4-en-1-amine, and it displayed excellent performances.

L'un des axes de recherche du laboratoire Synthèse Métallo-Induites consiste en le développement de nouveaux complexes métallacycliques à chiralité planaire. Le défi majeur de cette thèse, a été l'élaboration de nouvelles approches sélectives de synthèse de complexes cationiques et neutres métallacyliques à chiralité planaire dont le métal chélaté est un centrestéréogène pseudo-tétraédrique.Le projet de thèse fut initié lors de l'étude d'une réaction inhabituelle de cycloruthénation d'un ligand dérivé de la 2-phénylpyridine qui était capable de produire un complexe ruthénacyclique OC-6 triscationique, homobinucléaire et à chiralité planaire comme produit secondaire en une seule étape à partir de substrats simples. Ce type de produit homobinucléaire ne peut se former uniquement que lorsqu'un groupement fortement donneur comme le N,N-diméthylamino (-NMe2) est présent sur le ligand départ. C'est donc à la lumière de ce résultat que nous avons engagé une étude systématique de la synthèse de nouveaux composés iridacycliques à chiralité planaire. Les fragments métalliques positivement chargés (Cp*Ir2+, Cp*Ru+) et neutre (Cr(CO)3) pourraient p-coordiner un fragment aryle riche en électrons d'un composé cyclométallé suivant un cours stéréochimiqueconditionné par la nature des entités ainsi introduites. Une des conséquences inattendues de ces recherches est l'émergence du concept de chiralité constitutionnelle déportée qui a surgi lors de l'étude du comportement conformationnel du complexe endo dicationique IrIr(NMe2) dont les groupes méthyles portés par le substituant N,N-diméthylamino dénotent une diastéréotopicité remarquable en spectroscopie de RMN 1H.A cette quête fondamentale de sélectivité s'est aussi greffée une exploration des propriétés catalytiques de nos complexes qui se sont révélés comme d'excellents précatalyseurs pour la promotion de réactions comme l'oxydation de l'eau et l'hydroamination/hydrosilylation d'alcynes vrais.

This thesis describes the catalysed addition of X-H bonds (X = S, O and N) to alkynes using a range of novel rhodium(I) and iridium(I) complexes containing hybrid bidentate phosphine-pyrazolyl, phosphine-imidazolyl and phosphine-N heterocyclic carbene (NHC) donor ligands. The synthesis of novel bidentate phosphine-pyrazolyl, phosphine-imidazolyl (P-N) and phosphine-NHC (PC) donor ligands and their cationic and neutral rhodium(I) and iridium(I) complexes [M(P N)(COD)]BPh4, [M(PC)(COD)]BPh4, [Ir(P-N)(CO)2]BPh4 and [M(P-N)(CO)Cl] were successfully performed. An unusual five coordinate iridium complex with phosphine-NHC ligands [Ir(PC)(COD)(CO)]BPh4 was also obtained. Seventeen single crystal X-ray structures of these new complexes were determined. A range of these novel rhodium and iridium complexes were effective as catalysts for the addition of thiophenol to a variety of alkynes. Iridium complexes were more effective than rhodium analogues. Cationic complexes were more effective than neutral complexes. Complexes with hybrid phosphine-nitrogen donor were more effective than complexes containing bidentate nitrogen donor ligands. An atom-economical, efficient method for the synthesis of cyclic acetals and bicyclic O,O-acetals was successfully developed based on the catalysed hydroalkoxylation. Readily prepared terminal and non-terminal alkyne diols were cyclised into bicyclic O,O-acetals in quantitative conversions in most cases. The efficiency of a range of rhodium and iridium complexes containing bidentate P-N and PC donor ligands as catalysts for the cyclisation of 4-pentyn-1-amine to 2-methyl-1-pyrroline varied significantly. The cationic iridium complexes with the bidentate phosphine-pyrazolyl ligands, [Ir(R2PyP)(COD)]BPh4 (2.39-2.42) were extremely efficient as catalysts for this transformation. Increasing the size of the substituent on or adjacent to the donor led to improvement in catalytic activity of the corresponding metal complexes. The mechanism of the catalysed hydroalkoxylation was proposed to proceed by the initial activation of the alkyne via ?? coordination to the metal centre. The ?? binding of both aliphatic and aromatic alkynes to [Ir(PyP)(CO)2]BPh4 (2.44) was observed by low temperature NMR and no reaction between 2.44 and alcohols was observed. In contrast, the facility in which thiol and amine oxidatively added to 2.44 led the proposal that in the hydrothiolation and hydroamination reaction, the catalytic cycle commences with the activation of the X-H bond (X = S, N) by an oxidative addition process.

This thesis describes the catalysed addition of X-H bonds (X = S, O and N) to alkynes using a range of novel rhodium(I) and iridium(I) complexes containing hybrid bidentate phosphine-pyrazolyl, phosphine-imidazolyl and phosphine-N heterocyclic carbene (NHC) donor ligands. The synthesis of novel bidentate phosphine-pyrazolyl, phosphine-imidazolyl (P-N) and phosphine-NHC (PC) donor ligands and their cationic and neutral rhodium(I) and iridium(I) complexes [M(P N)(COD)]BPh4, [M(PC)(COD)]BPh4, [Ir(P-N)(CO)2]BPh4 and [M(P-N)(CO)Cl] were successfully performed. An unusual five coordinate iridium complex with phosphine-NHC ligands [Ir(PC)(COD)(CO)]BPh4 was also obtained. Seventeen single crystal X-ray structures of these new complexes were determined. A range of these novel rhodium and iridium complexes were effective as catalysts for the addition of thiophenol to a variety of alkynes. Iridium complexes were more effective than rhodium analogues. Cationic complexes were more effective than neutral complexes. Complexes with hybrid phosphine-nitrogen donor were more effective than complexes containing bidentate nitrogen donor ligands. An atom-economical, efficient method for the synthesis of cyclic acetals and bicyclic O,O-acetals was successfully developed based on the catalysed hydroalkoxylation. Readily prepared terminal and non-terminal alkyne diols were cyclised into bicyclic O,O-acetals in quantitative conversions in most cases. The efficiency of a range of rhodium and iridium complexes containing bidentate P-N and PC donor ligands as catalysts for the cyclisation of 4-pentyn-1-amine to 2-methyl-1-pyrroline varied significantly. The cationic iridium complexes with the bidentate phosphine-pyrazolyl ligands, [Ir(R2PyP)(COD)]BPh4 (2.39-2.42) were extremely efficient as catalysts for this transformation. Increasing the size of the substituent on or adjacent to the donor led to improvement in catalytic activity of the corresponding metal complexes. The mechanism of the catalysed hydroalkoxylation was proposed to proceed by the initial activation of the alkyne via ?? coordination to the metal centre. The ?? binding of both aliphatic and aromatic alkynes to [Ir(PyP)(CO)2]BPh4 (2.44) was observed by low temperature NMR and no reaction between 2.44 and alcohols was observed. In contrast, the facility in which thiol and amine oxidatively added to 2.44 led the proposal that in the hydrothiolation and hydroamination reaction, the catalytic cycle commences with the activation of the X-H bond (X = S, N) by an oxidative addition process.