The crystal structure of solvated Pt[CH₃C(CH₂PPh₂)₃][P(C₆H₄F)₃]

Abstract

The molecular structure of the compound Pt(tripod)P(C₆H₄F)₃½C₄H₈O where tripod = CH₃C- (CH₂PPh₂)₃, has been determined by single-crystal X-ray diffraction methods at 295 K. Crystals are triclinic, space group P1. Z 2, a 13.497(1), b 14.803(2), c 13.898(2) A, α 91.914(7), β 102.304(6), γ 97.319(6)°. Diffractometry (Mo Kα) has provided significant [I ≥ 3σ(I)] Bragg intensities for 9528 independent reflections within 0 < (sin θ;)/λ ≤ 0.705 Ǻ^-1.The structure has been refined by least-squares methods to R 0.040. The coordination of the zero-valent platinum atom is distorted tetrahedral with three Pt-P bonds, of lengths 2.292(1), 2.297(1), 2.303(1) Ǻ, to phosphorus atoms of the tripod ligand, and a fourth Pt-P(C₆H₄F)₃ bond of length 2.261(1) Ǻ. The P-Pt-P bond angles involving the phosphorus atom of the monodentate ligand are large [118.23(5), 127.18(6), 122.20(5)°], whereas the steric constraints related to the tripod ligand are reflected in the other P-Pt-P bond angles, none of which are very different from 90° [91.26(5), 99.56(5), 90.79(5)°]. We suggest that the short Pt-P(C₆H₄F), bond is qualitatively explained by greater 's' electron character in the metal σ orbital used in bonding with the monodentate ligand, and conversely more 'p' electron character in the platinum σ orbitals used in bonding with the tripod ligand. We discuss the lack of significant evidence for platinum to phosphorus π-bonding effects in the observed Pt-P bond lengths.