John D. Scott

Synthesis and polymerization of alkylplatinum complexes containing two vinyl groups

Abstract Oxidative addition of alkyl or acyl halides containing a vinyl substituent (RX: CH 2 CHO 2 CCH 2 Br, CH 2 CMeCO 2 CH 2 CH 2 Br, CH 2 CHCOCl, CH 2 CHC 6 H 4 CH 2 Cl) to [PtMe 2 (v-bipy)], v-bipy 4-methyl-4′-vinyl-2m,2′-bipyridine, gives the corresponding alkylplatinum(IV) complexes [PtXMe 2 R(v-bipy)], which contain two vinyl groups and thus are suitable precursors to cross-linked vinyl polymers with organoplatinum(IV) substituents. Each platinum(IV) monomer can exist in three isomeric forms, one formed by trans and two formed by cis oxidative addition.

Mechanism and energetics of reductive elimination of ethane from some tetramethylplatinum(IV) complexes

The new complexes cis-[PtMe4L2], L = MeNC or 2,6-Me2C6H3NC, decompose cleanly in the solid state or in solution to give ethane and cis-[PtMe2L2]. Studies using differential scanning calorimetry give a value of (PtMe)= 133 ± kJ mol–1for the mutually trans PtMe groups, and deuterium-labelling studies show that the reductive elimination step is intramolecular. Kinetic studies show that the reaction occures very largely after ligand dissociation and gives a value of k(PtCH3)/k(PtCD3)= 1.30 ± 0.04. It is suggested that an agostic interaction of one CH3Pt group in the five-co-ordinate intermediate precedes the reductive elimination step and reasons for this proposal are advanced.

Synthesis and properties of a methyl derivative of zeise's dimer

A methyl(ethylene)platinum(II) complex [Pt2(µ-Cl)2Me2(C2H4)2] has been prepared and characterized; it forms complexes [PtClMe(C2H4)L] where L = pyridine, Me2S, or C2H4, undergoes exchange with unsaturated reagents (un) where (un)= PhCHCHPh, CH(CO2Me)CH(CO2Me), or PhCCPh to give [Pt2(µ-Cl)2Me2(un)2], undergoes insertion with CF3CCCF3 to give, after treatment with pyridine, [PtCl{C(CF3)C(CF3)Me}(py)2], and reacts with Zeise;s dimer to give the unsymmetrical dimer [Pt2(µ-Cl)2ClMe(C2H4)2].