The transition-metal complexes of heterotopic phosphanylthiolato ligands are useful in various reactions which depend on the stereochemistry of the complexes. Bis-chelate complex [Pt(SCH2CH2PPh2-k2P,S)2] (1) was obtained in good yields by direct base-free substitution reaction of the corresponding phosphanylthiol (HSCH2CH2PPh2) with K2PtCl4 or by oxidative addition of the same phosphanylthiol to Pt(PPh3)4. In agreement with the antisymbiosis rule, complex 1 shows a cis-P,P arrangement in solid state crystallizing in the monoclinic system (C2/c). Density functional theory (DFT) calculations on 1 reveal the right characteristics for the preferred cis-P,P arrangement, rationalizing its formation. Direct base-free reaction of [PtCl2(1,5-cyclooctadiene)] with one equivalent of the same phosphanylthiol produce the trinuclear complex [PtCl(m- SCH2CH2PPh2-k2P,S)]3 (2) instead of the binuclear structure common in palladium and nickel derivatives. Crystals of 2 are triclinic (P1¯ ) showing a sulfur-bridging edge-sharing cyclic trinuclear complex with square-planar coordination geometry around the platinum atoms and a Pt3S3 cycle in skew-boat conformation. This preference for the trinuclear structure was rationalized mechanistically and through conceptual DFT

A. Polo thanks the Spanish Dirección General de Enseñanza Superior e Investigación Cient ífica (DGESIC) for financial support (project BQU2002-04070-C02-01). A. Poater thanks the Spanish Ministerio de Economí a y Competitividad (MINECO) for a Ramón y Cajal contract (RYC-2009-05226) and the European Commission for a Career Integration Grant (CIG09-GA-2011-293900). M. S. thanks the European Union for a Fonds Européen de Développement Régional (FEDER) fund (UNGI10-4E-801), the Generalitat de Catalunya for project 2014SGR931 and the Institució Catalana de Recerca i Estudis Avançats (ICREA) Academia 2014 prize, and MINECO through project CTQ2014-54306-P