Activity Of [Pt-2(mu-S)(2)(PPh3)(4)] (1) towards 1,4-dichlorobutane, 1,2-dichloroethane, alpha-alpha'-dichloro-o-xylene and alpha-alpha'-dichloro-m-xylene and the catalytic role of 1 in the syntheses of organosulfur materials was studied by in situ electrospray mass spectroscopy (ESMS). An intermediate, [Pt-2(mu-SC2H4S)(PPh3)(4)][PF6](2) (6) was isolated and characterized by single-crystal X-ray crystallographic diffractometry. In all reactions studied, the {Pt2S2} core is preserved, except for those involving excess NaBH4. Treatment of 6 with excess NaBH4 leads to the formation of mononuclear complex [Pt(eta-S2C4H8)(PPh3)]. (C) 2003 Elsevier Science B.V. All rights reserved.