Synthesis and characterization of platinum(II) complexes with terminal alkynes analogous to Zeise's salt - Structure of [K(18-crown-6)][PtCl3(PhC≡CD)] · CH2Cl2

Article abstract of DOI:10.1016/S0022-328X(97)00465-8

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 IR spectroscopy. The stretching frequencies v(≡C-H(D)) and v(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, P1, a = 10.155(2), b = 11.368(3), c = 14.047(2) A, α = 86.28(2), β = 70.42(1), γ = 77.64(2)°, Z = 2) reveals an angle between the PtCl₃ and Pt(C≡C) planes of 82.5(5)° and an out-of-plane bending of the phenyl group of 15.2(9)°. The phenyl group is twisted by 33.9(7)° 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) A, d(K1-C12) = 3.220(3) A).