Developing oxidation catalysts, understanding mechanisms of polyoxometalate-based oxidations, and systems for color-change detection technology.

摘要

Transition-metal anionic clusters are studied for green oxidation catalysis. Particular attention is paid to understanding the active catalytic species and the mechanism of the reaction. The O2-based oxidation of propane thiol by a gelating nonporous material is presented. The catalytic conversion 2-chloroethyl ethyl sulfide to the corresponding sulfoxide is presented for Ag2[(CH3C(CH2O)3) 2V6O13] and a [Fe(H2O)PW11O 39]4- based material. A series of catalytic systems were developed and explored in an attempt to determine the key intermediate in the rapid and selective catalytic aerobic oxidation of sulfides to sulfoxides by nitrogen oxides and bromide Sources of nitrogen oxides and bromide anion were critical to catalysis. The tetra-n-butylammonium salt of [gamma- SiW10O32(OH)4]4- was shown to be the precursor of an active species that catalyzes oxygen transfer from aqueous H2O2 to olefins. An acid dependent H 2O2-based reaction generates the active catalyst in solution via decomposition. A catalyst assembled in situ from monomeric components (TBA2WO4, HClO4) exhibits similar properties. The work presented herein continues the pursuit to isolate and characterize palladium and platinum-oxo units stabilized by polyoxometalate ligands. The development, characterization and optimization of a readily deployable color-change detection sensor for the chemical warfare agent mustard is also described.