Derivative chemistry of [Ru2(mu-bdt)(CO)(6)], a binuclear ruthenium(I) carbonyl complex containing a bridging benzene-1,2-dithiolate ligand

The known dithiolate-bridged ruthenium(I) complex [Ru-2(mu-bdt)(CO)(6)] (1) (bdt = benzene-1,2-dithiolate) has been prepared in fair yield (55%) by th e sequential treatment of RuCl3. nH(2)O with carbon monoxide, benzene-1,2-d ithiol and zinc in a one-pot reaction. Complex 1 reacts readily with monode ntate phosphanes to give, stepwise, the penta- and tetracarbonyl derivative s [Ru-2(mu-bdt)(CO)(6-n)(PR3)(n)] (n = 1, 2; R = Ph, Cy, iPr). However, the reaction of 1 with one equivalent of bis(diphenylphosphanyl)methane (dppm) affords a mixture of complex 1 and the disubstituted derivative [Ru-2(mu-b dt)(CO)(4)(eta(1)-dppm)(2)], in which the dppm ligands are monodentate. Thi s mixture is subsequently transformed into a polymeric material of formula [{Ru-2(mu-bdt)(CO)(4)}(mu-dppm)](n), which consists of binuclear {Ru-2(mu-b dt)(CO)(4)} units linked to each other by bridging dppm ligands. The use of two equivalents of dppm leads to [Ru-2(mu-bdt)(CO)(4)(eta(1)-dppm)(2)] in quantitative yield. The X-ray diffraction structure of [Ru-2(mu-bdt)(CO)(4) (PiPr(3))(2)] (3c) confirms that the phosphane Ligands are located in axial positions, cis to both sulfur atoms, and that the Ru-Ru distance is short [2.6753(7) Angstrom]. A comparative study of the reactivity of complexes 1 and 3c with the electrophiles H+, [Au(PPh3)](+), and HgCl2 has allowed the isolation of the derivatives [Ru-2(mu-H)(mu-bdt)(CO)(6-n)(PiPr(3))(n)][BF4] (n = 0, 2), [Ru2Au(mu-bdt)(CO)(6-n)-(PiPr(3)S)(n)(PPh3)][BF4] (n = 0, 2) a nd tBF41 (n = 0, 2) and [Ru2HgCl2(mu-bdt) (CO)(6-n)-(PiPr(3))(n)] (n = 0, 2 ), respectively.