Expedient, Direct Synthesis of (L)Pt(0)(1,6-diene) Complexes from H₂PtCl₆

Abstract

The one-pot synthesis of useful [Pt2(0)(η4-1,6-diene)3] complexes, directly from H2PtCl6·xH2O, has remained an unaddressed problem. We have found that the treatment of an i-PrOH solution of H2PtCl6·xH2O by (Me3SiO)2MeSi(CHCH2), in the presence of allyl ether (AE), followed by reaction of the in situ generated Pt(0) species with IPr carbene (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) enables the isolation of (IPr)Pt(AE) (1) in 50−70% yield. The scope of this method has been extended to other (L)Pt(1,6-diene) complexes (L = 1,3-dicyclohexylimidazol-2-ylidene, triphenylphoshine; 1,6-diene = diethyl 2,2-diallylmalonate (DAM)), and the molecular structure of the (IPr)Pt(DAM) (4) complex has been unequivocally determined by a single-crystal X-ray diffraction analysis. These results are significant for the formation of active L−Pt(0) fragments in catalysis.