Platinum(II) Complexes with 1‐Cyclohepta‐2,4,6‐trienyl‐diphenylphosphane, Ph2P(C7H7), and Alkyn‐1‐yl Ligands

Abstract

Abstract[1‐Cyclohepta‐2,4,6‐trienyl‐diphenylphosphane]platinum(II) dichloride (4) was prepared by the 1:1 reaction of (cod)PtCl2 (cod = η4‐cycloocta‐1,5‐diene) with the phosphane. The reaction of 4 with di(alkyn‐1‐yl)dimethylstannanes, Me2Sn(C≡C‐R)2 [R = H (a), Me (b), Ph (c), SiMe3 (d)], in boiling THF gave selectively in high yield the monoalkynyl complexes [Ph2P(C7H7)]Pt(Cl)C≡C‐R (6b,c,d), in which the alkyn‐1‐yl group is arranged in cis position with respect to the phosphorus atom, and the C7H7 ring is η2‐coordinated to platinum through the central C=C bond. The same reaction at room temperature afforded, again selectively and in high yield, the dialkynyl complexes [Ph2P(C7H7)]Pt(C≡C‐R)2 (7a‐d). The new complexes were characterised in solution by 1H, 13C, 29Si, 31P and 195Pt NMR spectroscopy, and the molecular structures of 4 and 7d were determined by X‐ray crystallography.