Alkyne Addition to a Metal-Stabilized Thiyl Radical: Carbon-Sulfur Bond Formation between 1-Octyne and [Ru(SP)3]+

The metal-stabilized thiyl radical complex [Ru(SP)(3)](+), [Ru-1](+), {SP = 2-(diphenylphosphanyl)benzenethiolate} adds 1-octyne across the cis-sulfur sites to yield the S-alkylated dithiolene product [Ru-1 center dot octyne](+). The product complex exists as a pair of inseparable geometric isomers, which were characterized by X-ray crystallography, P-31 NMR spectroscopy, and cyclic voltammetry. By using electrochemical methods, the rate constant for 1-octyne addition was determined as 8.7 x 10(3) M-1 s(-1).