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

Reaction of Pt(COD) 2 with Me 3 SiC⋮CPh and a bidentate chelating ligand leads to the formation of the corresponding donor-stabilized Pt-η 2 -alkyne complexes (PN)Pt(η 2 -Me 3 SiC⋮CPh) ( 1 ) and (dcpe)Pt(η 2 -Me 3 SiC⋮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(SiMe 3 )(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(SiMe 3 )(C⋮CPh) ( 4 ) is generated. Both Si−C(sp) bonds in Me 3 Si−C⋮C−C⋮C−SiMe 3 have been thermally activated by a (PN)Pt fragment to afford the dinuclear Pt(II) species (PN)Pt(SiMe 3 )−C⋮C−C⋮C−Pt(SiMe 3 )(PN) ( 6 ).