PdII and PtII complexes containing 1,1,4,7,10,10-hexaphenyl-1,4,7,10-tetraphosphadecane: First X-ray structure of a Pd-tetraphos complex
作者:Werner Oberhauser、Christian Bachmann、Peter Brüggeller
DOI:10.1016/0277-5387(94)00298-s
日期:1995.3
Pd-II and Pt-II complexes of meso- or rac-1,1,4,7,10,10-hexaphenyl-1,4,7,10-tetraphosphadecane (tetraphos-1, P4) have been prepared and characterized by X-ray diffraction methods, NMR spectroscopy (Pt-195H-1}, P-31H-1}), elemental analyses and melting points. The first X-ray structure of a Pd-tetraphos complex shows a strongly distorted square planar coordination in meso-[PdP4]Cl-4 (1). The Pd-atom deviates 0.231 Angstrom A from the best plane through the phosphorus atoms leading to an angle of 17.4 degrees between the planes through Pd and the phosphorus atoms of the PPh(2), and through Pd and the phosphorus atoms of the PPh groups, respectively. Rac-[PdClP4]Cl (2) shows a trigonal bipyramidal coordination. The destabilization of a square planar P4 arrangement in 2 is discussed in view of the X-ray structure of 1. Meso-(3) and rac-[Pd2Cl2(mu-Cl)P4]Cl (4) contain P4 in a chelating and bridging mode. In the case of Pt(II) three further derivatives of the earlier reported complexes meso- or rac-[Pt2Cl2(mu-Cl)P4]Cl have been prepared: rac-[Pt2Cl2(mu-Cl)(mu-t-dppe)P4]Cl (5), where t-dppe is trans-1,2-bis(diphenylphosphino)ethylene, and meso- (6) and rac-[Pt2Cl2(mu-Cl)(mu-pyrimidine)P4](PF6) (7). The compounds 5-7 are rare examples of triply bridged Pt(II) dimers containing two five-coordinate Pt(II) centres.