Synthesis and characterization of platinum(II) complexes with terminal alkynes analogous to Zeise's salt -: structure of [K(18-crown-6)][PtCl3(PhCCD)]•CH2Cl2

The reaction of [K(18-cr-6)][PtCl3(MeC-CMe)](1) (1a) with 1-alkynes RC=CH (R = n-Pr, n-Bu, t-Bu, Ph) and PhC=CD in methylene chloride at low temperatures results in the formation of [K(18-cr-6)][PtCl3(RC=CH)] (2a-d) and [K(18-cr-6)][PtCl3(PhC=CD)] (2e), respectively. The complexes were characterized by microanalysis as well as by NMR, Raman and LR spectroscopy. The stretching frequencies nu(=C-H(D)) and nu(C=C) are lowered by 141-151 cm(-1) and 159-200 cm(-1), respectively, due to the coordination of the alkyne to the PtCl3 unit. The molecular structure of 2e . CH2Cl2 (triclinic, <P(1)over bar>, a = 10.155(2), b = 11.368(3), c = 14.047(2) Angstrom, alpha = 86.28(2), beta = 70.42(1), gamma = 77.64(2)degrees, Z = 2) reveals an angle between the PtCl3 and Pt(C=C) planes of 82.5(5)degrees and an out-of-plane bending of the phenyl group of 15.2(9)degrees. The phenyl group is twisted by 33.9(7)degrees from the Pt(C=C) plane. There are tight contacts between the cation [K(18-cr-6)](+) and the anion [PtCl3(PhC=CD)](-) via the trans-chlorine and one of the cis-chlorines (d(K1-C13) = 3.331(3) Angstrom, d(K1-C12) = 3.220(3) Angstrom). (C) 1997 Elsevier Science S.A.