Olefin Hydroarylation Catalyzed by (pyridyl-indolate)Pt(II) Complexes: Catalytic Efficiencies and Mechanistic Aspects

A series
of Pt­(II) complexes of the type (N–N)­PtPh­(SR2) (N–N
= 2,2′-pyridyl-indolate) were prepared,
and their performance as catalysts for the hydroarylation of olefins
was assessed. Evidence that the catalysis is homogeneous and is Pt-mediated
is provided by control experiments with added hindered base (2,6-di-tert-butyl-4-methylpyridine) and Hg(0). Two potential catalytic
intermediates, (tBuPyInd)­PtPh­(C2H4) and (tBuPyInd)­Pt­(CH2CH2Ph)­(C2H4), were synthesized,
and their catalytic efficacy was explored. Additionally, decomposition
and deactivation pathways, including styrene formation via β-hydride
elimination and ligand reductive demetalation, were identified.