Stabilization of Trans Disilyl Coordination at Square-Planar Platinum Complexes

By using two different multidentate phosphinosilyl ligands, we prepared the two platinum complexes [Pt{PhP((o-C6H4)CH2SiMe2)2}PPh3] (3) and [Pt{P((o-C6H4)CH2SiMe2)2(o-C6H4)CHSiMe2)}PPh3] (4) exhibiting a trans configuration of the silicon atoms in a typical square-planar geometry around a Pt(II) center. Complex 4 results from intramolecular C–H activation of a methylene moiety by the third silicon atom of the original ligand and displays an anagostic C–H···Pt interaction, as supported by solution NMR data and solid-state X-ray diffraction analysis. The reactivity of 3 toward small molecules is also discussed. In the case of H2 and CO, the corresponding dihydride [PtH2{PhP((o-C6H4)CH2SiMe2)2}PPh3] (5) and dicarbonyl [Pt{PhP((o-C6H4)CH2SiMe2)2}(CO)2] (6) complexes were characterized, whereas reduction to Pt(0) and release of PPh3 and HSiMe3 were observed upon thermolysis in the presence of HBpin.