Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 180-182). Also available on the Internet.

Thesis (Ph. D.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on June 29, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Chemistry, University of Alberta." Includes bibliographical references.

Thesis (Ph. D.)--Montana State University--Bozeman, 2003. / Typescript. Chairperson, Graduate Committee: Rufus L. Cone. Includes bibliographical references (p. 361-380).

Thesis (Ph. D.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

Orientadores: Sergio Gama, Ekkes Bruck / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-10T04:26:45Z (GMT). No. of bitstreams: 1 Caron_Luana_D.pdf: 3120809 bytes, checksum: 0f270249e6bc452525873f2d4479ba9d (MD5) Previous issue date: 2008 / Resumo: Nesta tese de doutoramento são apresentados os resultados do estudo das propriedades magnéticas, magnetocalóricas e estruturais de algumas séries de compostos que são de interesse para aplicação em refrigeração magnética baseada no efeito magnetocalórico. Os métodos de preparação da série MnFe P1-xAsx são estudados de forma a otimizar o tempo de preparação e as propriedades magnétocalóricas. Uma nova série de compostos baseada na anterior, a MnFeGe1-xSix foi descoberta, apresentando transições de fase magnética de segunda ordem e uma variação linear dos parâmetros de rede em função da concentração de Si no intervalo 0 £ x £ 0,7. Também foi descoberto, associado à uma transição magnética de segunda ordem, o efeito magnetocalórico no composto MnFeSn cujo TC situa-se em torno da temperatura ambiente. Foi feito o estudo do efeito magnetocalórico dos compostos baseados no Mn2Sb com o Mn parcialmente substituído por Cr, V, Co e Cu e o Sb substituído por Ge. Nestes compostos uma transição do tipo Exchange Inversion é induzida pelas substituições, transformando o estado ferrimagnético em antiferromagnético em baixa temperatura, dando origem ao chamado efeito magnetocalórico inverso. Ainda foi desenvolvido um modelo fenomenológico para descrever tal transição e o efeito magnetocalórico associado. Por fim é reportado o efeito magnetocalórico colossal nos compostos M n1-xCux As, devido ao qual os métodos de medida magnéticos do efeito magnetocalórico são revistos. A partir dos resultados em diferentes procedimentos de medida, é proposta uma forma de medir o efeito em materiais altamente histeréticos que não leva a resultados espúrios / Abstract: On this PhD thesis some results on the magnetic, magnetocaloric and structural properties of some series of compounds suitable for applications on magnetocaloric effect-based refrigeration are presented. The FeMnP1-xAsx series preparation methods are studied in order to optimize their magnetocaloric properties as well as to shorten its preparation time. A new series of compounds based on the previous one was studied, the MnFeGe1-xSix. These compounds present a second-order magnetic phase transition and a linear change in lattice parameters with Si content on the 0 £ x £ 0.7 range. Also associated with a second-order phase transition, the magnetocaloric effect on FeMnSn was discovered around room-temperature. A careful study of Mn2Sb-based compounds with Mn partially substituted by Cr, V, Co and Cu and Sb by Ge was performed. On these compounds an Exchange Inversion transition is induced by substitutions taking the material from the ferrimagnetic to the antiferromagnetic state with decreasing temperature, giving rise to the so-called inverse magnetocaloric effect. A phenomenological theoretical model was also developed to describe such transitions and their associated magnetocaloric effect. Finally we report on the colossal magnetocaloric effect on Cu-substituted MnAs compounds. Due to this compound¿s unusual behavior, the magnetic measurements of the magnetocaloric effect are reviewed. Based on the results of different measurement procedures a new method of measurement for highly hysteretic compounds is proposed which leads to non spurious results / Doutorado / Materiais Magneticos e Propriedades Magneticas / Doutor em Ciências

Ph.D. / This thesis deals with the synthesis of nitrogen-donor compounds and their reaction with metal ions. The first type of nitrogen-donor compounds are the unconjugated diimines (N,N´-bis(diphenylmethylene)ethylenediamine (L1) and (N,N´-bis(diphenylmethylene)propylenediamine (L2). Compounds L1 and L2 were reacted with [NiBr2(DME)] or [NiCl2·6H2O] to form complexes (2.1a), (2.2a), (2.3a) and (2.4a). These nickel complexes were characterized by IR spectroscopy, elemental analysis and mass spectrometry. When the complexes were left in chloroform for prolonged periods, hydrolysis of the diimine ligand took place, leading to the formation of nickel complexes 2.1b, 2.2b, 2.3b and 2.4b. The identity of the hydrolysed nickel complexes 2.1b and 2.2b was confirmed by single crystal X-ray crystallography. Complex 2.1b crystallised in the P21/n space group, whilst 2.2b crystallised in the P-1 space group. Compounds L1 and L2 were also reacted with [PdClMe(MeCN)2] to form the palladium complexes (3.1) and (3.2). The palladium complexes were characterized by NMR spectroscopy, elemental analysis and single crystal X-ray crystallography. Attempts to recrystallize 3.1 from a dichloromethane solution led to the formation of 3.1a. Both complexes 3.1a and 3.2 crystallised in the P21/n space group. Complexes 3.1 and 3.2 were tested as catalysts for the Heck coupling reaction of iodobenzene with methyl acrylate or butyl acrylate at 80 C. The products from the coupling reactions were characterized by GC and NMR spectroscopy. These complexes were found to be highly active with 100% conversions observed in some instances. The second type of ligands that were prepared are the benzoylpyrazolyl compounds, (3,5-dimethylpyrazol-1-yl)phenylmethanone (C1), (3,5-ditertiarybutylpyrazol-1-yl)phenylmethanone (C2), (3,5-dimethylpyrazol-1-yl)-o-toluoylmethanone (C3), (3,5-ditertiarybutylpyrazol-1-yl)-o-toluoylmethanone (C4), (2-chlorophenyl)-(3,5-dimethylpyrazol-1-yl)methanone (C5), (2-chlorophenyl)-(3,5-ditertiarybutylpyrazol-1-yl)methanone (C6), (2-flourophenyl)-(3,5-dimethylpyrazol-1-yl)methanone (C7), (2-flourophenyl)-(3,5-ditertiarybutylpyrazol-1-yl)methanone (C8). These compounds were fully characterized using NMR spectroscopy, IR spectroscopy and elemental analysis. Compounds C1, C3, C5 and C7 were reacted with [NiBr2(DME)] to form nickel complexes (4.31-4.34). These nickel complexes were found to be insoluble in all common organic solvents and hence were characterized only by IR spectroscopy and elemental analysis. Compounds C1-C8 were also reacted with [PdCl2(MeCN)2] to form palladium complexes (4.35-4.42). Complexes 4.35-4.42 were characterized using NMR spectroscopy, IR spectroscopy, elemental analysis and in selected cases single crystal X-ray crystallography. Complex 4.39 crystallised in the C2/n space group and complex 4.42 crystallised in the P21/n space group. Attempts to recrystallize 4.37a led to the formation of 4.37b, which contains both 3,5-dimethylpyrazol-1-yl)-o-toluoylmethanone and 3,5-dimethylpyrazole as ligands. Complex 4.37b was confirmed by NMR spectroscopy and single crystal X-ray crystallography. Complex 4.37b crystallised in the Pbca space group. The formation of 4.37b is attributed to hydrolysis of 3,5-dimethylpyrazol-1-yl)-o-toluoylmethanone ligand in 4.37a due to the presence of adventitious water in the solvent. The palladium complexes (4.35-4.42) were tested as catalysts for the Heck coupling reaction of iodobenzene with butyl acrylate and also for the Suzuki coupling reaction of iodobenzene with phenylboronic acid or 4-chlorophenylboronic acid. In these reactions, complexes 4.35-4.42 were found to be highly active at 120 C. The pyrazolyl nickel and palladium complexes were further tested as catalysts in ethylene oligomerization reactions using EtAlCl2 as the co-catalyst. The nickel complexes were found to be the most active reaching TONs of 10.8105 g mol-1 h-1. The palladium analogues only gave TONs of up to 3.9105 g mol-1 h-1. The oligomers were characterized by GC and NMR spectroscopy and were found to be in the C10-C16 range, with C16 the most abundant olefin.

Ph.D. / Compounds, 2,6-bis(3,5-dimethylpyrazol-1-ylmethyl)pyridine (L1) and 2,6-bis(3,5-ditertbutylpyrazol-1-ylmethyl)pyridine (L2) were prepared by phase transfer alkylation of 2,6-bis(bromomethyl)pyridine with two mole equivalents of the appropriate pyrazole. Ligands L1 and L2 reacted with either [PdCl2(NCMe)2] or [PdClMe(COD)] to form mononuclear palladium complexes [(PdCl2(L1)] (1), [(PdClMe(L1)] (2), [(PdCl2(L2)] (3), [(PdClMe(L2)] (4). All new compounds prepared were characterised by a combination of 1H NMR, 13C NMR spectroscopy and microanalyses. The coordination of L2 in a bidentate fashion through the pyridine nitrogen atom and one pyrazolyl nitrogen atom has been confirmed by single crystal X-ray crystallography of complex 3. Reactions of 1, 2 and 3 with the halide abstractor NaBAr4 (Ar = 3,5-(CF3)2C6H3) led to the formation of the stable tridentate cationic species [(PdCl(L1)]BAr4 (5), [(PdMe(L1)]BAr4 (6) and [(PdCl(L2)]BAr4 (7) respectively. Tridentate coordination of L1 and L2 in the cationic complexes has also been confirmed by single X-ray crystallography of complexes 5 and 6. The analogous carbonyl linker cationic species, [Pd{(3,5-Me2pz-CO)2-py}Cl]+ (9) and [Pd{(3,5-tBu2pz-CO)2-py}Cl]+ (10), prepared by halide abstraction from [Pd{(3,5-Me2pz-CO)2-py}Cl2] and [Pd{(3,5-tBu2pz-CO)2-py}Cl2] with NaBAr4, were however less stable. While cationic complexes 5-7 showed indefinite stability in solution, 9 and 10 had t1/2 of 14 and 2 days respectively. Attempts to crystallise 1 and 3 from the mother liquor resulted in the isolation of the salts [PdCl(L1)]2[Pd2Cl6] (11) and [PdCl(L2)]2[Pd2Cl6] (12). Although when complexes 1-4 xviii were reacted with modified methylaluminoxane (MMAO) or NaBAr4, no active catalysts for ethylene oligomerisation or polymerisation were formed, activation with silver triflate (AgOTf) produced active catalysts that oligomerised and polymerised phenylacetylene to a mixture of cis-transoidal and trans-cisoidal polyphenylacetylene. Compounds 2-(3,5-dimethylpyrazol-1-ylmethyl)pyridine (L3) and 2-(3,5-di-tert-butylpyrazol-1-ylmethyl)pyridine (L4) were prepared by phase transfer alkylation of 2-picolylchloride hydrochloride with one mole equivalent of the appropriate pyrazole. Compounds 2-(3,5-bis-trifluoromethyl-pyrazol-1-ylmethyl)-6-(3,5-dimethyl-pyrazol-1-ylmethyl)-pyridine (L5) and 2-(3,5-dimethyl-pyrazol-1-ylmethyl)-6-phenoxymethyl-pyridine (L6) were isolated in good yields by reacting (2-chloromethyl-6-3,5-dimethylpyrazol-1-ylmethyl)pyridine with an equivalent amount of potassium salt of 3,5-bis(trifluoromethyl)pyrazolate and potassium phenolate respectively. L3-L6 react with either [Pd(NCMe)2Cl2] or [PdClMe(COD)] to give mononuclear palladium complexes 13-18 of the general formulae [PdCl2(L)] or [PdClMe(L)] where L = is the bidentate ligands L3, L4, L5 and L6 respectively. Single crystal X-ray crystallography of complexes 13, 15 and 16 has been used to confirm the solid state geometry of the complexes. In attempts to generate active olefin oligomerisation catalysts, the chloromethyl Pd(II) complexes 14 and 16 were reacted with the halide abstractor NaBAr4 in the presence of stabilising solvents (i.e Et2O or NCMe) but no catalytic activities were observed. Decomposition was evident as observed from the deposition of palladium black in experiments using Et2O. In experiments where NCMe was used as the stabilising solvent, the formation of cationic species stabilised by NCMe was evident from 1H NMR analyses. Reaction of complex 14 with NaBAr4 on a preparative scale in a mixture of CH2Cl2 and NCMe solvent gave the cationic complex [[PdMeNCMe(L3)]BAr4 (19) in good yields. Complex 17 reacted with NABAr4 to give tridentate cationic species [[PdMe(L5)]BAr4 (20) which is inactive towards ethylene oligomerisation or polymerisation reactions. The tridentate coordination of L5 in 20 has also been established by single crystal X-ray structure of 20. Catalysts generated from 18 and 19 catalysed ethylene polymerisation at high pressures to branched polyethylene; albeit with very low activity. The Choromethyl palladium complex 14 reacted with sulfur dioxide to form complex 21. The nature of the product has been established by 1H NMR, 13C NMR and mass spectrometry to be an insertion product of SO2 into the Pd-Me bond of 14. Compounds L1-L4 reacted with the nickel salts NiCl2 or NiBr2 in a 1:1 mole ratio to give the nickel complexes [NiCl2(L1)] (22), [NiBr2(L1)] (23), [NiCl2(L2)] (24), and [NiBr2(L2)] (25), [Ni2(μ2-Cl)2Cl2(L3)2] (26), [Ni2(μ2-Br)2Br2(L3)2] (27), [NiCl2(L4)] (29) and [NiBr2(L4)] (30) in good yields. Reaction of L3 with NiBr2 in a 2:1 mole gave the octahedral complex [NiBr2(L4)2] (28) in good yields. Complexes 22-30 were characterised by a combination micro-analyses, mass spectrometry and single crystal X-ray analyses for 27 and 30. No NMR data were acquired because of the paramagnetic nature of the complexes. When complexes 22-30 were activated with EtAlCl2, highly active olefin oligomerisation catalysts were formed. In the ethylene oligomeristion reactions, three oligomers: C11, C14 xx and C16 were identified as the major products. Selectivityof 40% towards α-olefins were generally obtained. In general catalysts that contain the bidentate ligands L3 and L4 were more active than those that contain the tridentate ligands L1 and L2. Dichloride complexes exhibited relatively higher catalytic activities than their dibromide analogues. Turn over numbers (TON) for oligomer formation showed high dependence on ethylene concentration. A Lineweaver-Burk analysis of reactions catalysed by 22 and 26 showed TON saturation of 28 393 kg oligomer/mol Ni.h and 19 000 kg oligomer/mol Ni.h respectively. Catalysts generated from complexes 22-30 also catalysed oligomerisation of the higher olefins, 1-pentene, 1-hexene and 1-heptene and displayed good catalytic activities. Only two products C12 and C15 were obtained in the 1-pentene oligomerisation reactions. The 1-hexene reactions also gave two products, C12 and C18, while 1-heptene oligomerisation reactions gave predominantly C14 oligomers. Five benzoazoles were used to prepare a series of palladium complexes that were invesitigated as Heck coupling catalysts. The compounds 2-pyridin-2-yl-1H-benzoimidazole (L7) and 2-pyridin-2-yl-benzothiazole (L8) were prepared following literature procedures. The new ligands 2-(4-tert-butylpyridin-2-yl)-benzooxazole (L9) and 2-(4-tert-butyl-pyridin-2-yl)-benzothiazole (L10) were prepared by ring closure of aminophenol and aminothiophenol with tert-butyl picolinic acid respectively. The ligand 6-tert-Butyl-2-(4-tert-butyl-pyridin-2-yl)-benzothiazole (L11) was prepared by intramolecular cyclisation under basic conditions is described. Reactions of L7-L11 with either [Pd(NCMe)2Cl2] or [Pd(COD)MeCl] afforded the corresponding mononuclear palladium complexes [PdClMe(L7)] (31), [PdClMe(L8)] (32), [PdCl2(L9)] (33), [PdMeCl(L9)] (34), [PdCl2(L10)] (5), [PdMeCl(L10)] (36) and [PdMeCl(L11)] (37) as xxi confirmed by mass spectrometry and micro-analyses. The palladium complexes 31-37 were efficient Heck coupling catalysts for the reaction of iodobenzene with butylacrylate under mild conditions and showed good stability.

The major topics discussed are all relevant to the bright phosphorescent emissions of coinage metal complexes (Cu(I), Ag(I) and Au(I)) with an explanation of the theoretical background, computational results and ongoing work on the application in materials and optoelectronic devices. Density functional computations have been performed on the majority of the discussed complexes and determined that the most significant distortion that occurs in Au(I)-phosphine complexes is a near and beyond a T-shape within the P-Au-P angle when the complexes are photoexcited to the lowest phosphorescent excited state. The large distortion is experimentally qualified with the large Stokes' shift that occurs between the excitation and emission spectra and can be as large as 18 000 cm-1 for the neutral Au(I) complexes. The excited state distortion has been thoroughly investigated and it is determined that not only is it pertinent to the efficient luminescence but also for the tunability in the emission. The factors that affect tunability have been determined to be electronics, sterics, rigidity of solution and temperature. The luminescent shifts determined from varying these parameters have been described systematically and have revealed emission colors that span the entire visible spectrum. These astounding features that have been discovered within studies of coinage metal phosphorescent complexes are an asset to applications ranging from materials development to electronics.

Greater understanding and accurate predictions of structural, thermochemical, and spectroscopic properties of chemical compounds is critical for the advancements of not only basic science, but also in applications needed for the growth and health of the U.S. economy. This dissertation includes new ab initio composite approaches to predict accurate energetics of lanthanide-containing compounds including relativistic effects, and optimization of parameters for semi-empirical methods for transition metals. Studies of properties and energetics of chemical compounds through various computational methods are also the focus of this research, including the C-O bond cleavage of dimethyl ether by transition metal ions, the study of thermochemical and structural properties of small silicon containing compounds with the Multi-Reference correlation consistent Composite Approach, the development of a composite method for heavy element systems, spectroscopic of compounds containing noble gases and metals (ArxZn and ArxAg+ where x = 1, 2), and the effects due to Basis Set Superposition Error (BSSE) on these van der Waals complexes.

The reactions of diagonal and lateral Cp'Re(CO)2Br2 (where Cp' = n5-C5H5, n5-C5Me5) and (n5-CgH7)Re(CO)3 with reducing agents have been examined. Hydride reduction at -78 °C is observed to occur at the Cp ring in both CpRe(CO)2Br2 isomers, affording a thermally unstable [(n4 -C5Hg)Re(CO)2Br2]- complex. The product of hydride ring attack has been characterized by low-temperature IR and 1H NMR measurements in addition to 13C NOE and heteronuclear 2D NMR measurements. Reaction of lateral CpRe(CO)2Br2 with either MeLi or PhLi affords both Cp-ring attack and metalhalogen exchange, [CpRe(CO)2Br]- (1) while t-BuLi reacts exclusively via metal-halogen exchange. diag-CpRe(CO)2Br2 reacts with the above lithium reagents to yield the same metal-halogen exchange anion. Analogous reactions using diag- and lat-Cp*Re(CO)2Br2 (where Cp* = n5-CgMe5) afford only the corresponding rhenium metal-halogen exchange anion, [Cp*Re(CO)2Br] (2). The molecular structures of 1-[Li/15-Crown-5] and 2-PPP were established by X-ray crystallography. 1-[Li/15-Crown-5] crystallizes in the monoclinic space group P21 with a = 10.860(4) A, b = 13.116(5) A, c = 7.417(3) A, B = 105.26(3)0, V = 1018.7(3) A3 , and Z = 2. 2-PPP crystallizes in the orthorhombic space group Pbca with a = 20.646(5) A, b = 17.690(5) A, c = 17.553(3) A, and z = 8. Solution FT-IR studies of 2 in THF reveal the presence of only solvent-separated ion pairs when the gegencation is Li+, K+, or PPP+ from -70 °C to room temperature. 2-Na at room temperature displays a 39:61 mixture of carbonyl oxygen-sodium and solvent-separated ion pairs, respectively. These ion pairs reveals a reversible temperature-dependent equilibrium. The equilibrium constant has been determined by IR band shape analysis over the temperature range -70 °C to room temperature and values of AH and AS are reported. The reaction of the ring-attacked complex, diag-[(n4-C5H6)Re(CO)2Br2]- with PPh3, P(OPh)3, or Me3CNC leads to the formation of the CpRe(CO)2L. Treatment of [Cp'Re(CO)2Br]- with methyltriflate, TFA, and magic ethyl yields the corresponding diag-Cp'Re(CO)2Br(R) (R = CH3, H, C2H5) complexes based on in situ IR analysis. All of these functionalized complexes decomposed in solution over a period of days to give Cp'Re(CO)3 as the only isolable product (20-30 %). The reaction of the [Cp,Re(C0)2Br]- with Bu3SnH at 60 °C leads to the formation of diag-Cp'Re(CO)2(SnBu3)2, which was also synthesized independently by the deprotonation of diag-Cp'Re(CO)2H2 with Et3N in the presence of Bu3SnBr at room temperature. The reaction of Cp'Re(CO)2Br2 with Bu3SnH at room temperature was discovered to afford the dihydride in excellent yield and, thus represents an improved synthetic route for the synthesis of diag-Cp'Re(CO)2H2. The hydride reduction of (n5-CgH7)Re(CO)3 at room temperature leads to the immediate formation of [(n5-CgH7)Re(CO)2H]- complex, which has been characterized by IR analysis and 1H and 13C NMR spectroscopy.