Generation of (mu-Ethynediyl)(methylalkoxycarbene)diplatinum Complexes from Reaction of cis,trans-[(CO)(C6F5)2Pt(mu-eta2-C=CSiMe3)Pt(=CSiMe3)L2] with ROH (R = Et, Me)

Resumen

Reaction of cis-[Pt(C6F5)2(CO)(THF)] with trans-[Pt(C≡CSiMe3)2L2], followed by reaction of the neutral μ-η2-monoacetylide-bridged diplatinum intermediates cis,trans-[(OC)(C6F5)2-Pt(μ-η 2-C≡CSiMe3)Pt(Cxba≡CSiMe3)L 2] (L = PPh3 (1), PEt3 (2)) with alcohols (EtOH, MeOH) yields the (μ-ethynediyl)(methylalkoxycarbene)diplatinum species cis,trans-[(OC)(C6F5) 2-Pt-C≡C-Pt{C(Me)OR}L2] (L = PPh3, R = Et (3a), Me (3b); L = PEt3, R = Et (4a), Me (4b)), resulting from unexpected rearrangement chemistry involving bridging and terminal (trimethylsilyl)acetylide ligands. The X-ray molecular structure of the complex cis,trans-[(OC)(C6F5) 2Pt-C≡C-Pt{C(Me)OEt}(PEt3)2] (4a) has been determined. It crystallizes in the monoclinic system, space group P21/c with a = 15.216(3) Å, b = 14.197(4) Å, c = 18.167(5) Å, β = 107.99(2)°, V = 3733(2) Å3, and Z = 4. The two coordination planes around the platinum atoms adopt an almost eclipsed arrangement (dihedral angle 6.7°) rather than the staggered form found in similar diplatinum complexes. © 1995 American Chemical Society.