Thermal and Photochemical Silicon−Carbon Bond Activation in Donor-Stabilized Platinum(0)−Alkyne Complexes

Reaction of Pt(COD)2 with Me3SiC⋮CPh and a bidentate chelating ligand leads to the
formation of the corresponding donor-stabilized Pt-η2-alkyne complexes (PN)Pt(η2-Me3SiC⋮CPh) (1) and (dcpe)Pt(η2-Me3SiC⋮CPh) (3) (PN = (diisopropylphosphinodimethylamino)ethane; dcpe = bis(dicyclohexylphosphino)ethane). The nitrogen donor ligand in 1 facilitates
the cleavage of the Si−C(sp) bond, and the Pt(II) complex (PN)Pt(SiMe3)(C⋮CPh) (2) is formed
at room temperature. In contrast, the bisphosphino-substituted compound 3 has been isolated
as a thermally robust Pt(0) complex. However, the silicon−carbon bond in the latter
compound can be photochemically activated, and the oxidative addition product (dcpe)Pt(SiMe3)(C⋮CPh) (4) is generated. Both Si−C(sp) bonds in Me3Si−C⋮C−C⋮C−SiMe3 have
been thermally activated by a (PN)Pt fragment to afford the dinuclear Pt(II) species (PN)Pt(SiMe3)−C⋮C−C⋮C−Pt(SiMe3)(PN) (6).