Metallo 2,3-Disulfidothienoquinoxaline, 2,3-Disulfidothienopyridine, and 2-Sulfido-3-oxidothienoquinoxaline Complexes: Synthesis and Characterization.

The 2,3-disulfidothienoquinoxaline complexes of Cp(2)Mo and dppePd and the 2,3-disulfidothienopyridine complexes of Cp(2)Mo were obtained as products from the S(8) oxidation of the corresponding metallo-1,2-enedithiolate complexes. The analogous 2-sulfido-3-oxidothienoquinoxaline complexes of Cp(2)Ti, Cp(2)Mo, dppPd, and dppePt were prepared from 1-(quinoxalin-2-yl)-2-bromoethanone and the corresponding polysulfido complex. Both Cp(2)Mo{S(2)C(10)H(4)N(2)S} and Cp(2)Mo{SOC(10)H(4)N(2)S} have been characterized crystallographically. These complexes contain an extended planar ring where the metal is bound to substituents at the 2- and 3-positions of the thiophene ring. The oxidation products of the Cp(2)Mo derivatives all have EPR g values near 1.98 and (97/95)Mo hyperfine of </= 8.5 G. All of the complexes have a visible band assigned to an intraligand transition (IL). The excitation of a room-temperature DMSO solution of dppePt{SOC(10)H(4)N(2)S} leads to an emission at 690 nm with a phi = 0.005. Lifetime measurements were best fit as the sum of two exponential decays with lifetimes of 6 and 0.3 ns.