Thermal Decomposition of Di(cycloalkyl)bis(triethylphosphine)platinum(II) Complexes

Article abstract of DOI:10.1021/ja00402a026

The thermal decomposition of three di(cycloalkyl)bis(triethylphosphine)platinum(II) complexes < cycloalkyl = cyclopropyl (L2Pt(c-C₄), cyclopentyl (L2Pt(c-C₅)2> have been examined.The mechanisms of decomposition of L2Pt(c-C₄) and L2Pt(c-C₅) are similar to those established in greater detail for diethylbis(triethylphosphine)platinum(II).The individual steps in solutions containing low concentrations of free triethylphosphine are dissociation of triethylphosphine and creation of a vacant coordination site, β-hydride elimination, and reductive elimination of cycloalkane (Scheme I); either the first or the third of these steps may be rate limiting.At high , another path having two triethylphosphines on platinum in the rate-determining transition state is important.Both enthalpic and entropic terms are important in determining which mechanism for decomposition is followed.Thermal decomposition of L2Pt(c-C₃)2 is complex and it is not presently understood: isomerization of cis-L2Pt(c-C₃)2 to trans-L2Pt(c-C₃)2, hydrogen transfer from L to the cyclopropyl group, and opening of the cyclopropyl ring are all competitive processes.