This award in the Inorganic, Bioinorganic, and Organometallic Program supports research by Dr. Daniel L. Reger of the Chemistry Department, University of South Carolina at Columbia, on coordination compounds of post-transition metals, specifically, Sn, Pb, Ga, In, and Tl. Compounds will contain bidentate and tripod-tridentate poly(pyrazolyl)borate ligands, which have previously exhibited a variety of coordination numbers depending on the size of the metal. By modification of the pyrazolyl ring, steric control of the extent of oligomerization will be attempted. In addition, hydride, alkoxide and amide derivatives will be synthesized and thermal decomposition of new alkyl metal complexes will be studied. The solution structure of the previously-prepared tin complexes will be investigated using NMR methods. Some work on compounds containing related polyphosphinoylmethanide ligands is also planned. %%% The ability of the later elements of Groups 13 and Group 14, namely tin, lead, gallium, indium and thallium, to form coordination compounds has not been studied extensively. The new coordination compounds which will be prepared in this project may be useful for preparation of semiconductors and optoelectronic devices by chemical vapor deposition. Water-soluble gallium and indium complexes might find utility in radiolabeling studies.