REACTIVITY OF OXOMOLYBDENUM(VI), OXOMOLYBDENUM(V), AND OXOMOLYBDENUM(IV) COMPOUNDS AS CONTROLLED BY SULFUR CHELATE LIGANDS

A series of cis-dioxomolybdenum(VI) complexes of the type MoO2(L-L)2 was prepared with a variety of chelating monoanions (L-L) to examine their relative stabilities. Also prepared were some related molybdenum(V) and -(IV) compounds. Reactivity of the oxo ligand in MoO2(L-L)2 was investigated to examine the ligand effects. Complexes MoO2(L-L)2, with L-L=dialkyldithiocarbamato (R2dtc) or similar sulfur-containing ligands, were found effective in the dehydrogenation of hydrazobenzene to azobenzene and oxygenation of PPh3, while those with O,O and O,N chelate ligands were inactive. Condensation of monoarylhydrazine with MoO2(L-L)2 occurs to give MoO(⎓NNHAr)(L-L)2 (L-L=thioxinato), Mo(N⎓NAr)2(L-L)2 (L-L=oxinato) or Mo2(N⎓NAr)3(L-L)4 (L-L=R2dtc), depending on the chelating ligands. These reactivities are discussed in terms of the electronic effect of the ligands. © 1979, American Chemical Society. All rights reserved.