Hydrido-organometallic complexes of platinum(II). X-Ray crystal structure of trans-[PtH(C6H4F-p)(PPh3)2]

Abstract

A series of compounds trans-[PtH(R)(PPh₃)₂][R = C₆H₄Y-p(Y = Me, OMe, F, or Cl), C₆H₄Me-o, C₆H₃Cl₂-2,5, C₆HCl₄-2,3,4,5, C₆HCl₄-2,3,4,6, C₆Cl₅, or C₆F₅], cis-[PtH(C₆F₅)(PPh₃)₂], and cis-[PtH(Ph)(dppe)](dppe = Ph₂PCH₂CH₂PPh₂) have been obtained by decarboxylation of formate complexes, or by the reaction of the halogeno complexes with NaBH₄. The compounds have been characterized by i.r. and n.m.r. (¹H, ³¹P, and ¹⁹⁵Pt) spectroscopy. The molecular structure of trans-[PtH(C₆H₄F-p)(PPh₃)₂] has been determined by a single-crystal X-ray structural analysis. The crystals are orthorhombic, space group Pcab, with a= 25.304(5), b= 23.963(5), c= 11.530(3)Å, and Z= 8. Dimethyl acetylenedicarboxylate inserts into the Pt–H bond of trans-[PtH(R)(PPh₃)₂](R = C₆H₄Cl-p, C₆H₄Me-p, or C₆H₄Me-o) to give the corresponding σ-vinyl complexes, but other alkynes and olefins do not react. The thermal stability in solution has also been studied; decomposition takes place via reductive elimination to give RH. The results obtained are explained in terms of the electronegativity and the size of the ligands and the configuration of the complexes.