This award from the Inorganic, Bioinorganic and Organometallic Chemistry Program will support an investigation of the chemistry of sulfur atoms which are part of metal-sulfur cluster compounds. Such compounds are useful models of the active sites of a number of important enzymes and also comprise an important class of catalysts, some of which are used in the chemical industry. The objective of the project is to investigate sulfur-nitrogen covalent interactions which result from the reactions of nitrogen substrates at sulfur as bound in sulfidometal complexes. Initial emphasis will be on dimolybdenum(V) sulfur- bridge systems, and both free radical and nucleophilic pathways to the formation of N-S bonds will be examined. Specific nitrogen substrates to be examined include diazonium salts, azo compounds, NO/NO+ compounds, sulfenamide precursors and metal dinitrogen complexes. Expected products for these substrates are, respectively, diazosulfide complexes, MSNNR; sulfenylhydrazines, MSNRNHR; thionitrite compounds, MSNO; metallosulfenamides, MSNR2; and MSNNM' complexes. Reactions will be monitored and products characterized by spectroscopic methods, including NMR (P-31, N-15, proton, C-13), EPR and IR, as well as by X-ray crystallography, as appropriate.
