Studies on metal-acetylene complexes : V. Crystal and molecular structure of bis(triphenylphosphine)(1-phenylpropyne)platinum(0), [P(C 6H 5) 3] 2(C 6H 5C CCH 3)Pt 0

Abstract

The acetylene complex (P(C 6H 5) 3) 2Pt(C 6H 5CCCH 3) crystallizes in the monoclinic space group P2 1 with a = 14.840(4), b = 9.558(3), c = 13.553(4)Å and β = 102.74(2)°. The observed density of 1.47(2) g cm -3 agrees with the value of 1.480 g cm -3, calculated for M = 835.8 and Z = 2. Three dimensional X-ray diffraction intensity data were collected on an automatic four circle diffractometer using Mo radiation. The structure was solved by the heavy atom method and refined by Fourier and full matrix least-squares techniques on F. The final conventional agreement factor for the converged model is 0.042, using 2843 observations with I>3σ( I). The coordination geometry about the Pt atom is essentially trigonal, if the coordinated triple bond of the acetylene is assumed to occupy one coordination site. The acetylene ligand adopts a cis-bent configuration, with a mean departure from linearity of 40(1)°. The coordinated triple bond length is 1.277(25) Å. The plane of the phenyl substituent of the acetylene is inclined at an angle of 10.4° with the plane of the acetylene ligand. The mean Pt-(acetylene) distance is 2.029(15) Å. The structural results indicate that the acetylene is considerably perturbed on coordination, consistent with the observation that Δν(C≡C) is 478 cm -1.