ASSOCIATION OF OXO-MOLYBDENUM DITHIOLENE COMPLEXES WITH A MULTIAMIDE ADDITIVE AND ITS INFLUENCE ON THE EASE OF O-ATOM TRANSFER

To regulate the reactivity of dithiolene dioxomolybdenum(VI) complexes , two systems were studied: (1) chelate recognition with a diamide add itive, 1,3-bis(isobutyrylamino)benzene (1); (2) a dithiolene complex w ith four amide substituents, (n-Pr4N)(2)[(MoO)-O-IV{S2C2(CONH2)(2)}(2) ]. 0.5(i-PrOH). DMF (2) (S2C2(CONH2)(2) = 1,2-dicarbamoylethylene- 1,2 -dithiolate). Both amide compounds, the additive 1 and the complex 2, were designed to form NH ... S and/or NH ... O hydrogen bonding with t hiolate ligands in ((MoO)-O-IV)(2+) and ((MoO)-O-IV)(2+) complexes. Ti tration analyses indicate the presence of a 1:1 complex in CH2Cl2 solu tion. This association causes changes in solubility and reactivity of the molybdenum complexes. When the additive was mixed with a DMSO-do s olution of (NEt(4))(2)[(MoO)-O-IV{S(2)C2(COOMe)(2)}(2)] (3) (S2C2(COOM e)(2) = 1,2-di(methoxycarbonyl)ethylene-1,2-dithiolate), the rate of r eduction of Me(3)NO was increased by a factor of 6. An acceleration wa s also observed for compound 2. It appeares that NH ... S hydogen bond ing is modulating the system.