Synthesis, Structure, and Catalytic Oxidation Chemistry from the First Oxo−Imido Schiff Base Metal Complexes

The molybdenum oxo−imido complex, [Mo(O)(NtBu)Cl2(dme)] (1), was obtained from the reaction between [MoO2Cl2(dme)] and [Mo(NtBu)2Cl2(dme)]. Reactions between [Mo(O)(NR)Cl2(dme)] (where R = tBu or 2,6-iPr2C6H3) and the disodium Schiff base compounds Na2(3,5-tBu2)2salen, Na2(3,5-tBu2)2salpen, and Na2(7-Me)2salen afforded the first oxo−imido transition metal Schiff base complexes: [Mo(O)(NtBu){(3,5-tBu2)2salen}] (2), [Mo(O)(NtBu){(3,5-tBu2)2salpen}] (3), and [Mo(O)(N-2,6-iPr2C6H3){(7-Me)2salen}] (4), respectively. The compounds [Mo(NtBu)2{(3,5-tBu2)2salpen}] (5) from [Mo(NtBu)2(NHtBu)2] and [Mo(N-2,6-iPr2C6H3)2{(7-Me)2salen}] (6) from [Mo(N-2,6-iPr2C6H3)2(NHtBu)2] (7) are also reported. Compounds 1−7 were characterized by NMR, IR, and FAB mass spectroscopy while compounds 3, 4, and 5 were additionally characterized by X-ray crystallography. In conjunction with tBuOOH as oxidant, compound 3 is a catalyst for the oxidation of benzyl alcohol to benzaldehyde and cis-cyclooctene and 1-octene to the corresponding epoxides.