SYNTHESIS, CHARACTERIZATION, AND REACTIVITY OF A PLATINUM(0) DIMER - PT2(MU-CO)(CO)2(MU-DPPM)2

The zerovalent platinum dimer [Pt2(mu-CO)2(mu-dppm)27 (1) (dppm = Ph2PCH2PPh2) has been prepared from [Pt2Cl2(mu-dppm)2] (2) via sodium borohydride reduction under carbon monoxide and from [Pt2(mu-dppm)3] (3) by substitution of a dppm ligand with CO. This latter reaction is readily reversible and can undergo several cycles of carbonylation-decarbonylation. Complex 1 undergoes typical oxidative addition reactions; it is readily protonated to yield [Pt2(H)(CO)(mu-dppm)2]-(p-CH3C6H4SO3).C6H6 (4). With I2, 1 reacts to yield [Pt2I2(mu-dppm)2] (5), and reaction with CH3I produces [Pt2(mu-I)(CH3)2(mu-dppm)2]I (6).