SYNTHESIS, REACTIVITY AND REDOX PROPERTIES OF DINUCLEAR MOLYBDENUM-SULFUR COMPLEXES

摘要

This paper reports the synthesis of dinuclear Mo(V) complexes containing the Mo2S42+ core. Complexes are prepared using the starting material (NH4)(2)MO(2)(S-2)(6) .2H2O for which a new high yield preparation is presented. Reaction of Mo-2(S-2)(6)(2-) With eight equivalents of the monodentate thiol, PhSH, gives Mo2S82-, i.e. (eta(2)-S-2)MoS(mu-S)(2)Mo(eta(2)-S-2)(2-), which has one terminal disulfido and one sulfide ligand in each molybdenum coordination sphere and has a bis(sulfido) bridge rather than the bis(disulfido) bridge of the starting material. The Mo2S82- anion is identical to that formed by the reaction of MoS42- with PhSSPh by an induced internal electron transfer process. Reaction of (NH4)(2)Mo-2(S-2)(6) . 2H(2)O with a large excess of PhSH yields Mo2S4(SPh)(4)(2-) in which the Mo2S42+ core is bound by four monodentate thiolate ligands. The reaction of (NH4)(2)Mo-2(S-2)(6) . 2H(2)O With excess of a variety of S-containing bidentate ligands gives high yields of Mo2S42+ core products with one bidentate, dithiolate on each molybdenum. The reactions involve reduction of the disulfido ligands in Mo-2(S-2)(6)(2-) to sulfide ligands, four of which remain in the coordination spheres of the two molybdenum atoms. All reactions and interconversions involve the maintenance of molybdenum in the oxidation state V. The complexes are of the general form Mo(2)S(4)L(2)(n-)(n = 0, L = i-Bu(2)NCS(2), Et(2)NCS(2), NH(CH3)CH2C(CH3)S, NH2CH2C(CH3)S, C6H4SNH2; n = 2, C6H4S2, CH3C6H3S2, C6H4SNH, SCH2CH2S). The X-ray crystal structures of (PPh(4))(2)[Mo2S8] and (NMe(4))(2)[Mo2S4(SPh)(4)] are reported. The structures are compared with other crystallographically characterized complexes containing the syn and anti Mo2S42+ cores. Infrared and UV-visible spectroscopic and electrochemical data are given for all of the new complexes reported. [References: 35]