Product distribution and stereochemistry in the reaction of the unsymmetrical bis(phosphine) Ph2P(CH2)6P(Et)Ph with platinum(II) salts

Article abstract of DOI:10.1021/ic00142a018

The new unsymmetrical bis(phosphine) Ph₂P(CH₂)₆P(Et)Ph has been synthesized, and its reactions with platinum(II) salts have been studied. The formation of the cis or trans isomer with the ligand is critically dependent on the choice of the platinum(II) salt used as the starting material: potassium tetrachloroplatinate(II) yields the cis isomer, and Zeise's salt yields the trans isomer, while bis(benzonitrile)dichloroplatinum(II) gives a cis-trans mixture. The complexes are characterized by ³¹P NMR and infrared spectroscopy, elemental analysis, and molecular weight data. The ³¹P NMR spectrum of the trans complex is analyzed and explained in terms of the presence of different dimeric units present in solution. The new symmetrical bis(chiral phosphine) Ph(Et)P(CH₂)₆P(Et)Ph and its platinum(II) complexes have been synthesized in order to confirm the spectral assignments. On the basis of the ³¹P NMR spectra obtained, it is now possible to predict which unsymmetrical bis(phosphine)-platinum(II) complexes will give ³¹P NMR spectra capable of complete analysis at 36.4-MHz field strength. The formation of the various isomers is also rationalized.