Year of Publication
Arts and Sciences
David A. Atwood
This theses presents the synthesis and characterization of Cd(II)-, Pb(II)- and Hg(II)-aminoethanethiolates in aqueous media. 2-Aminoethanethiolate, a versatile sulfur andnitrogen (S/N) based ligand was used due to its resemblance to the naturally occurringamino acid, cysteine. The work is presented in four major parts: first, backgroundinformation on the versatile structural chemistry of Cd, Pb and Hg-thiolates with S/Ncontaining ligands; second, synthesis and characterization of Cd(II) with 2-aminoethanethiolates; third, synthesis and characterization and structural chemistry ofPb(II) with 2-aminoethanethiolates; and fourth, synthesis and characterization of Hg(II)-2-aminoethanethiolates in solution- and solid-state with emphasis on the mechanisticpathways for the formation of clusters.The compounds reported here are synthesized by direct addition of the metal saltsand the ligand in deionized water. For Cd(II)-thiolates, insoluble products (77 - 80 and 82- 84) due to the formation of oligomers and polymers were obtained. In Pb(II)-thiolates(85 - 89), the structural chemistry is variable due to the extensive array of coordinationenvironments Pb can acquire. This can be related to the stoichiometry of the reaction aswell as the reaction conditions. The structural trends in Cd(II)- and Pb(II)-thiolates arenot observed in the Hg(II)-thiolates. Rather the halide influences the formation ofmolecular as well as non-molecular structures. Systematic pathways for the formation ofthe compounds based on a variety of commonly observed structural 'building blocks' arepresented. For Cl, Br derivatives, a four-coordinate intermediate, [Hg(SR)2X2] (88 - 96)and for I derivatives three-coordinate intermediates, [HgI(SR)2] and [HgI2(SR)] (97 -100) can be considered as building units. The compounds were characterized withIR/Raman, NMR, MS, Uv-Vis and X-ray crystallography.
Bharara, Mohan Singh, "Cd(II)-, Pb(II)- AND Hg(II)-2-AMINOETHANETHIOLATES" (2006). University of Kentucky Doctoral Dissertations. 294.