Ce travail de thèse traite de l'étude de la coordination de ligand phosphorés comportant une double liaison P=C sur des métaux riches, notamment le Ni(0) et le Pt(0). La coordination donne lieu à une isomérisation des fonctions phosphaalcènes en benzophospholane par insertion du phosphore dans une liaison C−H du supermésityle lié au phosphore. Un mécanisme réactionnel a été proposé. Ce mécanisme, appuyé par des calculs théorique, rationalise les observations expérimentales (notamment les intermédiaires observés). Une autre partie du travail s'intéresse à la coordination de ligand de type phosphaalcène à polarité inversée par la présence d'un ou plusieurs atomes d'azote en alpha du carbone de la liaison P=C. Leur capacité a donner deux paires libres a été étudiée ainsi que leur éventuelle application comme précurseurs de phosphinidènes.

This thesis details the synthesis and coordination chemistry of twenty-five nitrogencontaining heterocyclic ligands, nineteen of which were previously unreported compounds. These ligands were designed for use as synthons for the formation of molecular cages, so contain multiple coordination sites capable of bridging multiple metal atoms. The majority of molecular cages in the literature are formed by rigid bridging ligands, whereas the ligands studied in this research incorporate a higher level of flexibility, thereby lessening the degree of control over the self-assembly process and increasing the number of possible structures that can be formed upon reaction of these ligands with meal salts. Three of the new ligands synthesised were two-armed bridging ligands, which were reacted with a wide variety of metal salts to investigate what self-assembly products were formed. The complexes characterised include a M₃L₃ cyclic trimer, a range of coordination polymers of varying dimensionality, a range of dimeric products and a series of M₄L₆ cage-like molecular squares. However, the majority of ligands studied were three-armed, potentially tripodal compounds, which were envisaged as potential components of M₃L₂ or M₆L₄ molecular cages. The products of self-assembly of these ligands with various metals salts were shown to include a variety of discrete tri- and tetranuclear complexes, a range of coordination polymers of varying dimensionality and interpenetration, and a complex M₆L₄ assembly that appears to be a collapsed coordination cage. Unfortunately some of the ligands synthesised were shown to decompose in the presence of various metal salts, a phenomenon already identified in the literature. Analogues of these decomposition products were synthesised deliberately to identify the potential of a known tridentate ligand as a metallosupramolecular synthon. ¹H NMR spectroscopy, mass spectrometry, elemental analysis, thermogravimetric analysis and X-ray crystallography were used to study the compounds synthesised. The crystal structures of five ligands and fifty-one complexes are discussed.

The synthesis and coordination chemistry of eleven bridging ligands, eight of which are new compounds, are described. These ligands are all based on the tridentate terpyridyl system. The other metal ion binding sites of these ligands contain pyridine/bipyridine/pyrazole rings or amine/azamacrocycles domains. In these ligands, the two metal ion binding sites are differentiated by the number of atoms in each site, the configuration of the binding site or the types of donor atom that are present. This binding site differentiation allows to use the different coordination properties of the binding sites to control the regiochemistry of the complexation, ensuring that the correct metal ion is incorporated at the correct binding site in the ligand. Many of the complexes synthesised are mono-ruthenium(II) complexes where Ru(II) ions are situated in the terpyridyl sites of the ligands. These include heteroleptic Ru(II) complexes of the type [Ru(ttp)(L)]2+, where ttp is 4'-(p-tolyl)-2,2':6',2ʺ- terpyridine, and L is the bridging ligand. Reactions of the Ru(II) complexes with a range of metal ions including Co(III) ion have been investigated. The Ru(II) complexes can be classified into three main categories depending on the type of ligands that have been employed: (1) Ru(II) complexes which can react with Co(III) ions to form heterodinuclear Ru(II)-Co(III) complexes; (2) Ru(II) complexes which react only with Ag(I) ions and no other common metal ions that we have tried; (3) Ru(II) complexes with no detectable ability to coordinate other common metal ions. Following standard cobalt chemistry, some heterodinuclear Ru(II)-Co(III) complexes of the type [(ttp)Ru(cymt)Co(X)2]3+, where X = NO2 -, Cl-, and OH-, have been successfully prepared from the corresponding Ru(II) complexes. In these heterodinuclear complexes, anions such as NO2 -, Cl-, or OH- can be readily attached to the Co(III) ions. However, attachment of a neutral species such as en ligands to the Co(III) ions in the complexes proved to be more difficult. Reactions of heterodinuclear Ru(II)-Co(III) complexes with en ligands result in removal of the cobalt ions from the complexes. This is may be a result of a significant difference in the overall charges between the complexes with anionic and the complexes with neutral ligands (3+ vs 5+). Higher overall charge of the complexes when protonable ligands such as monodentate en are present, may destabilize the complexes even more. A combination of NMR spectroscopy, ESI-MS, UV-vis spectroscopy, elemental analysis, and X-ray crystallography has been used to characterise the ligands and their complexes. The crystal structures of one new ligand and sixteen complexes are described.

This thesis describes the preparation and characterisation of a number of homochiral coordination and metallosupramolecular assemblies. These species were formed from the reaction of chiral pyridine and quinoline containing ligands and metal ions. The combination of traditional coordination chemistry and supramolecular interactions led to a range of polymeric and network structures being formed. The ligands used in this thesis can be divided into two broad categories: alkaloids and ligands derived from them, and amino acid-based ligands. In the first category three new ligands were synthesized, and a variety of routes towards alkaloid-based homochiral ligands were investigated. The second category focused on three ligand motifs, and resulted in the preparation of 16 ligands. These two categories of ligands were reacted with a range of metal salts to investigate their coordination and supramolecular chemistry. The structure of twenty complexes was determined by single crystal X-ray crystallography. The complexes had a range of structures, with discrete and polymeric species being formed. Hydrogen bonding was an important feature in the supramolecular chemistry of the complexes, playing a different role in different series of complexes. Two chiral coordination polymers and one chiral coordination network were synthesized. All three of these structures possessed directionality to some degree: in the coordination network and one of the polymers the directionality is counterbalanced by the opposite directionality being present in the crystal, while the second coordination polymer is generated by the screw axis present and has a high degree of overall directionality.

This thesis details the synthesis and coordination chemistry of twenty-five nitrogencontaining heterocyclic ligands, nineteen of which were previously unreported compounds. These ligands were designed for use as synthons for the formation of molecular cages, so contain multiple coordination sites capable of bridging multiple metal atoms. The majority of molecular cages in the literature are formed by rigid bridging ligands, whereas the ligands studied in this research incorporate a higher level of flexibility, thereby lessening the degree of control over the self-assembly process and increasing the number of possible structures that can be formed upon reaction of these ligands with meal salts. Three of the new ligands synthesised were two-armed bridging ligands, which were reacted with a wide variety of metal salts to investigate what self-assembly products were formed. The complexes characterised include a M₃L₃ cyclic trimer, a range of coordination polymers of varying dimensionality, a range of dimeric products and a series of M₄L₆ cage-like molecular squares. However, the majority of ligands studied were three-armed, potentially tripodal compounds, which were envisaged as potential components of M₃L₂ or M₆L₄ molecular cages. The products of self-assembly of these ligands with various metals salts were shown to include a variety of discrete tri- and tetranuclear complexes, a range of coordination polymers of varying dimensionality and interpenetration, and a complex M₆L₄ assembly that appears to be a collapsed coordination cage. Unfortunately some of the ligands synthesised were shown to decompose in the presence of various metal salts, a phenomenon already identified in the literature. Analogues of these decomposition products were synthesised deliberately to identify the potential of a known tridentate ligand as a metallosupramolecular synthon. ¹H NMR spectroscopy, mass spectrometry, elemental analysis, thermogravimetric analysis and X-ray crystallography were used to study the compounds synthesised. The crystal structures of five ligands and fifty-one complexes are discussed.

The coordination chemistry of compounds featuring P-P and P—Sb bonds has been investigated to define the fundamental features of bonding in these systems. New reaction methodologies to form P—P bonds have been evolved based on careful consideration of bond strengths in the gas and condensed phase. Insights revealed from systematic studies of molecular structures have been used to augment and expand the scope of existing models for structural prediction (e.g. VSEPR theory). Unique classes of catena-antimony compounds have been discovered, illustrating a remarkable structural and electronic diversity for this heavy p-block metal. Detailed mechanistic examinations have revealed a previously unrecognized mode of ligand activation for phosphine complexes of very electrophilic acceptors. Stable sources of the hitherto unisolated and highly reactive tris-triflate reagents, E(OTf)3 (E = P, As, Sb, Bi), have been prepared and their coordination chemistry as Lewis acids and oxidizing agents has been mapped. Collectively, the findings described here span a range of coordination chemistry paradigms for p-block elements that may be broadly applicable across the periodic table. A robust plan has been proposed for applying these insights towards the preparation of fundamentally interesting molecular frameworks and towards new strategies for small molecule activation. / Graduate / 0488 / 0485

xxi, 172 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Main group supramolecular chemistry is a rapidly expanding field that combines the tools of coordination chemistry with the unusual and frequently unexpected coordination preferences exhibited by the main group elements. Application of established supramolecular design principles to those elements provides access to novel structure types and the possibility of new functionality introduced by the rich chemistry of the main group. Chapter I is a general review of the field of main group supramolecular chemistry, focusing in particular on the aspects of coordination chemistry and rational design strategies that have been thus far used to prepare polynuclear "metal"-ligand assemblies. Chapter II is a discussion of work toward supramolecular assemblies based on the coordination preferences of lead(II), in particular focusing on the 2-mercaptoacetamide and arylthiolate functionalities to target four-coordinate and three-coordinate geometries, respectively. Several possible avenues for further pursuing this research are suggested, with designs for ligands that may provide a more fruitful approach to the coordination of lead(II). Chapter III deals with the preparation of As 2 L 3 assemblies based on flexible ligand scaffolds. These assemblies exhibit structural changes in response to temperature and solvent, which may provide some insight into the subtle shape requirements involved in supramolecular guest binding. Chapter IV continues this work with an examination of how ligand structure affects mechanical coupling of stereochemistry between metal centers when the chelate ring is completed by a secondary bonding interaction such as the As-π contact. Finally, Chapter V presents a crystallographic and synthetic study of the nature of the interaction between pnictogens and arene rings. This interaction is ubiquitous in the coordination chemistry performed in the Johnson laboratory; understanding the role these interactions play in determining the final structure of supramolecular assemblies is vital to the preparation of more complex structures. Chapter VI presents a set of conclusions and outlook for future work on lead(II) supramolecular assemblies and the dynamic assemblies prepared from flexible organic scaffolds. This dissertation contains previously published and coauthored material. / Committee in charge: Kenneth Doxsee, Chairperson, Chemistry; Darren Johnson, Advisor, Chemistry; David Tyler, Member, Chemistry; Victoria DeRose, Member, Chemistry; Stephen Remington, Outside Member, Physics

Submitted by Erika Demachki (erikademachki@gmail.com) on 2017-08-09T18:18:27Z No. of bitstreams: 2 Dissertação - Renato Rabelo de Souza Filho - 2017.pdf: 3321540 bytes, checksum: 7bdb3245e17c32ea854853600a863553 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-08-10T13:29:04Z (GMT) No. of bitstreams: 2 Dissertação - Renato Rabelo de Souza Filho - 2017.pdf: 3321540 bytes, checksum: 7bdb3245e17c32ea854853600a863553 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-08-10T13:29:04Z (GMT). No. of bitstreams: 2 Dissertação - Renato Rabelo de Souza Filho - 2017.pdf: 3321540 bytes, checksum: 7bdb3245e17c32ea854853600a863553 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-07-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The synthesis, spectroscopic characterization, structural study and magnetic properties of four new compounds of formula [Co(bpcam)2]ClO4dmsoH2O (1), [Co(bpcam)2]2[Co(NCS)4]dmsoH2O (2), [Ni(bpcam)2]H2O (3) e [Cu(bpcam)Cl(H2O)] (4) [bpcam = bis(2-pyrimidylcarbonyl)amidate] are reported. The Co(II)-assisted hydrolysis of 2,4,6-tris(2-pyrimidyl)-1,3,5-triazine (tpymt) in mild conditions leads to a mononuclear unit of [CoIII(bpcam)2]+ which is isolated as perclorate (1) and tetrakis(N-thiocianate)cobaltate(II) (2) salts. The compounds 3 and 4 are obtained by reacting Hbpcam with the metallic salts nickel(II) perchlorate hexahydrate (3) and copper(II) chloride dihydrate (4) in stoichiometric ratios. Differently from the literature data, the hydrolysis of tpymt in the presence of copper(II) chloride also results in 4, which contains bpcam-. Each bpcamgroup in 1-4 acts as a tridentate ligand being coordinated to the cobalt(III) (1 and 2)/nickel(II) (3)/ copper(II) (4) ions through three nitrogen atoms in a meridional arrangement giving rise to six-coordinate (1 and 3) or five-coordinate (4) metallic ions, whereas six-coordinate cobalto(III) and four-coordinate cobalt(II) coexist in 2. Cyclic voltammetry of 1 in acetonitrile shows the occurrence of one quasi reversible CoIII ↔ CoII process. Variable-temperature magnetic susceptibility measurements on samples of 2-4 were carried out in the temperature range 1.9-295 K. The continuous decreasing of T from 2,68 cm3mol-1K at room temperature to 1.32 cm3mol-1K at 1,9 K observed for 2 is assigned to zero-field splitting (ZFS) of pseudotetraedral complex [Co(NCS)4]2- anion. A Curie law for a magnetically isolated nickel(II) ion in the high temperatures domain is observed for 3 and the small decrease of T below 10 K being due to zerofield splitting effects. The magnetic behavior for 4 follows a Curie-Weiss law for magnetically isolated copper(II) ions with occurrence of weak antiferromagnetic intermolecular interactions. The fitting of experimental data of 2 and 3 through the spin Hamiltonian [M = Co (2) e Ni (3)] led to the following values: = 2.37 (2) e 2.12 (3) e || = 34.7 (2) e 1.72 (3). Finally, the analysis of the magnetic susceptibility data of 4 leads to a Curie-Weiss law with gCu = 2,08 e  = 0,8 K, being  the Weiss constant. / A síntese, caracterização espectroscópica, elucidação da estrutura cristalina e estudo das propriedades magnéticas de quatro novos compostos de fórmula [Co(bpcam)2]ClO4dmsoH2O (1), [Co(bpcam)2]2[Co(NCS)4]dmsoH2O (2), [Ni(bpcam)2]H2O (3) e [Cu(bpcam)Cl(H2O)] (4) [bpcam- = bis(2-pirimidilcarbonil)amidato] são descritas nesse trabalho. A hidrólise do 2,4,6-tris(2- pirimidil)-1,3,5-triazina (tpymt) assistida pelo íon cobalto(II) em condições brandas resulta na unidade mononuclear de [CoIII(bpcam)2]+ que é isolada na forma de sais de perclorato (1) e tetrakis(N-tiocianato)cobaltato(II) (2). Os compostos 3 e 4 são obtidos reagindo o pré-ligante Hbpcam com os sais metálicos perclorato de níquel(II) hexahidratado (3) e cloreto de cobre(II) dihidratado (4) em quantidades estequiométricas. Diferentemente dos dados da literatura, a hidrólise do tpymt na presença de cloreto de cobre(II) resulta em 4, o qual contém bpcam-. Cada ligante bpcam- atua como um ligante tridentado que se coordena aos íons cobalto(III) (1 e 2)/níquel(II) (3)/cobre(II) (4) através dos três átomos de nitrogênio do sítio terpiridina em um arranjo meridional dando origem a íons metálicos hexacoordenados (1 e 3), pentacoordenado (4), enquanto íons cobalto(III) hexacoordenados e cobalto(II) tetracoordenados coexistem em 2. O voltamograma cíclico de 1 em acetonitrila mostra a ocorrência de um processo CoIII ↔ CoII quase reversível. As medidas da dependência da susceptibilidade magnética em amostras de 2-4 foram realizadas na faixa de temperatura de 1,9-295 K. O decréscimo contínuo de T de 2,68 cm3 mol-1K a temperatura ambiente para 1,32 cm3 mol-1 K a 1,9 K observado para 2 decorre do desdobramento a campo zero (ZFS) do complexo aniônico pseudotetraédrico [Co(NCS)4]2-. Uma Lei de Curie para íons níquel(II) magneticamente isolados é observada a altas temperaturas para 3 e o pequeno decréscimo de T abaixo de 10 K é atribuído ao desdobramento a campo zero. O comportamento magnético de 4 segue uma Lei de Curie-Weiss para íons cobre(II) magneticamente isolados com ocorrência de interações intermoleculares antiferromagnéticas fracas. O ajuste dos dados experimentais de 2 e 3 pelo Hamiltoniano [M = Co (2) e Ni (3)] levou aos seguintes valores: = 2,37 (2) e 2,12 (3) e || = 34,7 (2) e 1,72 (3). Por fim, a análise dos dados de susceptibilidade magnética de 4 levou a uma Lei de Curie-Weiss com gCu = 2,08 e  = 0,8 K, sendo  a constante de Weiss.

Neste trabalho realizamos estudos sobre interações entre o composto 2,3,5,6-tetra(-piridil)pirazina (tppz) e Eu3+ em diferentes situações. Na primeira delas fizemos um estudo detalhado sobre as interações que ocorrem, em solução, entre o complexo tris(tenoiltrifluoroacetonato)európio(III), Eu(ttfa)3, e a tppz, em que verificamos que a tppz age como um supressor de luminescência, provavelmente através de uma segunda esfera de coordenação. Foram feitos, também, experimentos para o isolamento de cristais de complexos entre tppz e Eu3+, porém em nenhum dos métodos utilizados o complexo foi isolado, pois, quando o meio reacional voltava à temperatura ambiente a tppz precipitava. Por fim, como última tentativa de se obter complexos entre tppz e Eu3+, foram obtidos filmes por meio da técnica de Langmuir-Blodgett (LB) a partir de monocamadas mistas contendo 1-octadecanol e tppz, uma vez que a tppz sozinha não possui atividade superficial. Como resultado, foram obtidos filmes com os quais, através da espectroscopia de fotoluminescência, constatamos a formação do complexo. / In this work, we have conducted studies on the interactions of 2,3,5,6-tetra(-pyridyl)pyrazine (tppz) with Eu3+ in different situations. In the first of them, we have made a detailed study on the ongoing interactions in solution between tris(thenoiltrifluoroacetonate)europium(III), Eu(ttfa)3 and tppz, where it was verified that tppz act as a luminescence suppressor, probably through a second coordination sphere. Also, we have performed experiments with the aim of isolation crystals of complexes formed by tppz and Eu3+. However, in none of the methods used the complexes were isolated, because tppz precipitated when the reaction medium returned to the room temperature. As a last attempt to obtain the complexes between tppz and Eu3+, Langmuir-Blodgett (LB) films were formed from mixed monolayers containing 1-octadecanol and tppz, since tppz alone does not show surface activity. As a result, we have obtained films in which the complex formation was confirmed by photoluminescence spectroscopy.

Cette thèse porte sur l’étude de nouveaux carbènes N-hétérocycliques dont les atomes d'azote sont substitués par des groupes étendus alkylfluorényle (AF). Les caractéristiques principales de ces coordinats sont leur fort encombrement stérique, la modularité de ce dernier, et la proximité créée dans les complexes correspondants entre les groupes AF et le métal coordiné.La première partie de ce travail décrit la synthèse et la caractérisation d'un ensemble de sels d’azolium, précurseurs de cette nouvelle famille de NHCs. Ces composés ont d'abord été utilisés pour la préparation de complexes de palladium de type "Pd-PEPPSI-NHC", complexes qui se sont avérés très efficaces en couplage de Suzuki-Miyaura entre acides arylboroniques et chlorures d’aryle para-substitués. Des études structurales et RMN ont montré que dans leur complexes, les NHC formés agissent comme des pinces bimodales, c'est-à-dire combinant une interaction covalente (la liaison M-Carbène) et deux interactions non-covalentes impliquant les groupes AF. Dans certains complexes linéaires de l’or(I) et du cuivre (I), ces interactions faibles entre le métal et des liaisons C-H alentours ont permis la coordination non-optimale du centre métallique qui, à l’état solide, se retrouve hors de l’axe formé par le doublet non liant du carbène. Enfin, un complexe de type CuCl(NHC) dont l’encombrement stérique est variable a été préparé. Il s’est avéré être un excellent catalyseur d’hydrosilylation d’aldéhydes et de cétones. A ce jour, il possède l’une des plus grandes activité et longévité (TONs jusqu’à 1000) pour ce type de complexe / This thesis deals with a series of N-heterocyclic carbene ligands (NHCs) in which the N atoms bear expanded alkylfluorenyl (AF) substituents. Special focus has been put on the steric properties of these new ligands, as well as their influence on catalytic reactions involving Pd and Cu centres.The first part of this work describes the synthesis of a series of AF-substituted azolium salts suitable for the preparation of palladium PEPPSI-NHC complexes. These turned out to be very active in Suzuki-Miyaura cross-coupling reactions between para-substituted aryl chlorides and arylboronic acids. Structural and NMR studies revealed that in all the complexes, the NHC ligand displays a "bimodal pincer" type behaviour, that is functions as a tridentate ligand bound to the metal through both covalent and non covalent bonds, the former involving the carbenic C atom, the latter CH atoms of the wingtips.In the second part of the study, a series of linear [AuCl(NHC)] and [CuCl(NHC)] complexes were prepared. In some of them were observed weak CH•••M interactions involving the alkyl chains fixing the metal centre in a position below the NHC ring plane. This leads to an unusual coordination of the ligand able to freeze out the movement of the metal centre during its natural oscillation about the M-carbene axis.In the last part of this thesis, one of the [CuCl(NHC)] complexes synthesised was shown to be highly efficient in the catalytic hydrosilylation of functionalised/sterically crowded aldehydes and ketones (TONs up to 1000). Its high stability was attributed to the variable encumbrance of the ligand.