| Summary: | 博士 === 臺灣大學 === 化學研究所 === 95 === A series of 3d transition metal complexes were investigated in this dissertation, of which bonding characteristics and the electronic configuration of metal centers were pursued. Single crystal X-ray diffraction experiment at low temperature was applied. An aspherical multipole model was introduced subsequently to give a better description of total electron density distribution, based on which topological analysis was also carried out. Molecular orbital calculations and single-point theoretical calculations at density-functional-theory level (DFT) were performed as well for comparison.
In the first part three Cu-complexes, [CuI(phen)(μ-NCS)], [CuII2(phen)2(NCS)2(μ-OH)2•2H2O] and [CuII(phen)2(NCS)2], were studied. Though, same ligands (phen and NCS-) were found in all three compounds, of which local environments around Cu centers were different (coordination number = 4, 5 and 6, respectively). All Cu-ligand bonds are classified as transit closed-shell interaction (or polarized covalent bond) according to the corresponding positive Laplacian ( 3.90(1) ~ 12.28(1) e/Å5) and negative total energy densities ( -0.11 ~ -0.46 Hartree/Å3) given by the topological analysis. In addition, weak interactions such as hydrogen bonds and π-π stacking interactions were observed as well supported by the numerical evidence on the bond path.
In the second part a series of complexes constructed by 3d transition metal and nicotinic acid ([FeIII(C5H4NHCOO)(μ-SO4)(μ-OH)(H2O)] and [MII(C5H4NCOO)2(H2O)4] where M = Mn, Fe, Co, Ni, Cu, Zn) were investigated. In these iso-structural compounds different metal centers are crystallized in roughly the same local coordination environment, of which the oxidation states and the corresponding bonding characteristics (M-L) are inspected. Local charge concentrations addressed on atoms in the first coordination shell are clearly toward metal centers showing the σ-donor behavior. All the metal-ligand bonds in these complexes are also classified as transit closed-shell interaction due to the positive Laplacian ( 3.22(1) ~ 12.08(1) e/Å5) and negative total energy densities ( -0.01 ~ -0.12 Hartree/Å3). Besides, wd-block contraction of the 3d transition metal centers and the Jahn-Teller distortion around Cu ones were observed as well.
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