| Co-Investigator(Kenkyū-buntansha) |
UMETANI Shigeo Kyoto University, Institute for Chemical Research, Instructor., 化学研究所, 助手 (80160315)
KIHARA Sorin Kyoto University, Institute for Chemical Research, Associate Professor., 化学研究所, 助教授 (60161543)
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| Research Abstract |
There is, at present, a need for a rational approach toward ligand design for selective complexation of metals in solution not only in the field of analytical chemistry but in other several branches of science, such as therapeutic reagents for metal intoxication, design of antibiotics, assign of imaging agents in the body, metal extractants in hydrometallurgy, metal sequesting agents in detergents, biological cation transport systems and environmental chemistry. It is necessary to find out a rigid new ligand for coordinating space and/or to prepare the ligand having a novel function by introducing, e.g., sterically hindered group to it in order to get more selective chelating agents.
The present report describes chiefly thermal properties and extractions of metal polypyrazolylborate chelates and extractions of such organometallic compounds as organogermanium species. Four polypyrazolylborate ligands, HB(Me_2PY)_3^-, HBpz_3^-, Bpz_4^- and H_2Bpz_2^-, were synthesized, and these chelates of the first transition metals and IIA group metals were characterized by thermal analysis and complementary techniques. Relative thermal stability decreases in the order of the shielding degree of the ligands, HB(Me_2pz)_3^- > HBpz_3^- > Bpz_4^- > H_2Bpz_2^-. The most striking aspect of the present results was that Mg chelates of HB(ME_2PY)_3^- and HBpz_3^- were easily sublimed. The extractions of metals with such novel acylpyrazolones as bis(acylpyrazolone) derivatives and acylpyrazolones with bulky substituents, were also studied.
The extractions of organogermanium such as mono- and tri-methyl germanium (MMGe, TMGe) and monophenyl germanium (MPGe) species from hydrogen and/or lithium chloride solution into chloroform or carbon tetrachloride phase were performed. The formation constants between the organogermanium species and halogenide ions were determined by the extraction method.
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