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Mercury has been an element of great industrial importance since early times.This wide utilization of the element has led to pervasive mercury contamination in theglobal environment. Due to mercury's high toxicity, this is a matter of great concern. Anumber of methods, includ ing phytoremediation, filtration, and precipitation/chelation,have been investigated to remove mercury from the environment. Unfortunately, thesemethods are not entirely satisfactory for the in-situ remediation of mercury from aqueousenvironments.The hypothesis of this dissertation is that this can best be accomplished by theaddition of a large and flexible sulfur-based chelate, that will bind mercury in atetracoordinate and presumably tetrahedral environment, to mercury-contaminatedwaters. Although this proved difficult due to the tendency of these ligands to decomposeinto smaller, sulfur-containing rings, the synthesis and characterization of such a chelatewas achieved. Several potential mercury-binding ligands were eventually synthesizedsignificant amounts of mercury (91-100%) from the contaminated solutions, in one caselowering the mercury levels in the water to below the CVAF detection limits. Theresulting solids lost little (andlt;15 ppb) of their mercury during leaching studies.This work demonstrates the use of tetradentate chelates in precipating Hg2+ fromwater to produce stable mercury- ligand precipitates. A calculation for the quantification ofthe geometry of a four-coordinate compound was also developed and applied to aluminum,gallium, and mercury compounds. This calculation could also be applied to the mercurycompounds described in this thesis once X-ray structures become available

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Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: James A. Holcombe. Vita. Includes bibliographical references. Also available from UMI.

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Hemilabile ligands attracted much attention in past thirty years because they were effectively utilized in the field of coordination chemistry and homogenous catalysis. We have synthesized four tridentate iminophosphine ligands (o-Ph2P(C6H4)-C(H)=N-(CH2)n-R, n = 2, R = SnBu, LPNS1; n = 3, R = SMe, LPNS2; n = 3, R = OMe, LPNO3; and n = 3, R = NMe2, LPNN4) and one tridentate aminophosphine ligand (o-Ph2P(C6H4)CH2N(H)(CH2)3NMe2, LPNHN5) in this work. The structures of the iminophosphine copper(I) complexes were determined by the carbon-chain length between imino-nitrogen and third donor atom, the coordination ability of the third donor atom, and the nature of the anions (i.e. its donor ability and atomic radius). An unexpected tetranuclear copper(I) iodide complex [(CuI)2(LPNN4)]2 (16) was obtained due to the larger atomic radius of iodide ion. The ligand LPNN4 displayed versatile coordination behavior after complexing with some late transition metals such as Pd(II), Ag(I), Zn(II), Cd(II). These tridentate ligands may act as PN-chelator or PNE-chelator (E = S, N¡¦). Both chelating and bridging modes were observed at the same time in Cu(I) and Ag(I) complexes. In Zn(II) complex, however, chelating by LPNN4 chelated only occurred through its N donor atoms. In term of the reactivity study of these complexes, we found that the complex [Cu(LPNN4)(CH3CN)0.2](BF4) (17) would successful react with Na(SCN), NaN3, and PhCCH/KOH to generate corresponding substitution products. However when reacted with PhCCC(O)OH/KOH, copper complexes bearing LPNN4 could not give the corresponding substituted carboxylate copper(I) product and gave the complex [Cu(CCPh)(LPNN4)]2 (18) via auto-decarboxylation instead.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 103-119). Also available on the World Wide Web.

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