Carbon-sulfur bond formation via alkene addition to an oxidized ruthenium thiolate

Bulk oxidation of [Ru(DPPBT)(3)], 1b, (DPPBT = 2-diphenylphosphinobenzenethiolate) in the presence of ethylene yields [(ethane- 1,2-diylbis(thio-2,1 -phenylene)diphenylphosphine) ruthenium(11)] hexafluorophosphate, [2a]PF6, from the addition of the alkene across cis sulfur sites. During oxidation, the absorption bands of 1b at 540, 797, and 1041 nm decrease in intensity. The resulting complex [2a](+) displays a single redox couple at +804 mV. The +ESI-MS of [2a](+) shows a parent ion peak at m/z = 1009.1013, and the P-31 NMR spectrum displays chemical shift values of delta = 61.0, delta(2) = 40.3, and delta(3) = 37.5 with coupling constants of J(12) approximate to J(13) approximate to 30 Hz and J(23) = 304 Hz. Oxidation of [2a](+) by one electron at a holding potential of +1000 mV yields [(ethane- 1, 2-diylbis(thio-2, 1 phenylene)diphenyl phosphine)ruthenium(Ill)] hexafluorophosphate, [2b][PF6](2). The EPR of [2b][PF6](2) displays a rhombic signal with g(1) = 2.09, g(2) = 2.04, and g(3) = 2.03. Oxidation of lb in the presence of alkenes including 1-hexene, styrene, cyclohexene, and norbornene yields products similar to [2a](+). Each of these products was further oxidized to an analogue of [2b](2+). Complex [2a](+) was also prepared, as the bromide salt, from [PPN][Ru(DPPBT)(3)] (PPN [1a]; PPN = bis(triphenylphosphoranylidene)ammonium) and 1,2-dibromoethane. The complex [2a]Br crystallizes as thin yellow plates in the monoclinic space group P2(1)/c with unit cell dimensions of a 10.2565(9) angstrom, b = 13.2338(12) angstrom, c = 38.325(3) angstrom, and beta = 93.3960(10)degrees.