Doctor of Philosophy (PhD)
Four Ni(II) complexes have been obtained with the pyridyltriazole ligand, bpt, or the bis(pyridyltriazole) ligand, m-xpt, in chapter 2. This work was carried out as a comparison with the previously established coordination chemistry of copper(II) with bpt and m-xpt. Initially, the reaction between Ni(II) and bpt only produced one mononuclear compound, [Ni(bpt)2(H2O)2](NO3)2 (1). In order to study the formation of Ni-bpt and Ni-m-xpt complexes in solution, mixtures of Ni(NO3)2 and ligand (m-xpt or bpt) were prepared in different ratios and their UV-Vis spectra measured. The analysis and simulation by the computer program ZSQUAD suggested corresponding individual species of [Ni(bpt)n]2+ and [Ni2(m-xpt)n]4+ (n = 1, 2, 3). Meanwhile, two more complexes of [Ni(bpt)3](PF6)2 (2) and [Ni2(bpt)4(N3)2](PF6)2·2C4H10O (3) (C4H10O = Diethyl Ether) were successfully isolated by introducing N3− and PF6− into the reaction mixture. And one dinuclear complex, [Ni2(m-xpt)2(C2O4)](NO3)2 (4), was prepared to support the formulation of [Ni2(m-xpt)2]4+.
Chapter 3 is part of a study of the formation of copper(II) oxalate complexes. Two Cu complexes with oxalate, Cu(bpt)(C2O4)(DMF) (7) and Cu2(bpt)2(NO3)2(DMF)2(C2O4) (8), were prepared through multiple-steps reactions among Cu(NO3)2, bpt and ascorbic acid. The oxalate was a decomposition product of ascorbic acid. A polymer compound, [Cu(bpy)(C2O4)]n (10), was synthesized through mixing Cu2(bpy)2(OH)2(NO3) with dehydroascorbic acid and Dabco (bpy = bipyridine, Dabco = 1,4-diazabicyclo[2.2.2]octane). Another complex, [Cu2(bpy)2(Dabco)(C2O4)]n(PF6)2n (11), was obtained by adding Dabco into solution of [Cu(bpy)2]2+. Dabco functioned as a reducing agent in these reactions and decomposed to oxalate.
Chapter 4 describes the reactions between Pd(CH3CN)4(BF4)2 and m-xpt or p-xpt in mixture solvent of CH2Cl2 and (CH3)2CO. These experiments were assumed to prepare dimer structures similar to copper(II) and nickel(II) complexes. Colorless crystal, [Pd2(m-xpt)2](DMSO)6(BF4)4 (12), was formed. [Pd2(p-xpt)2]4+ was supported by mass spectra.
Chapter 5 describes a side product, Cu(bpy)(C4H4O6) (13), that is formed in a reaction of [Cu(bpy)2(NO3)](NO3), ascorbic acid and Dabco. C4H4O62− is an uncommon product from ascorbic acid degradation. Both inter- and intramolecular hydrogen bonds of O—H···O are found in the crystal structure of (13).
Gao, Sen, "Transition Metal Complexes of Pyridyltriazole and Bipyridine Ligands" (2020). LSU Doctoral Dissertations. 5353.
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