121832-67-5Relevant articles and documents
Six- and Five-co-ordinate Ruthenium(II) Complexes with 1,2-Bis(dicyclohexylphosphino)ethane. X-Ray Crystal Structure of the d6 Five-co-ordinate PF6
Mezzetti, Antonio,Zotto, Alessandro Del,Rigo, Pierluigi,Pahor, Nevenka Bresciani
, p. 1045 - 1052 (2007/10/02)
Six- and five-co-ordinate complexes of ruthenium(II) with the bulky diphosphine ligand 1,2-bis(dicyclohexylphosphino)ethane (dcpe) have been prepared.In solution, octahedral trans- (X = Cl or Br) and trans- can dissociate giving the unsaturated species (1+) and (1+), respectively.Phosphorus-31 n.m.r. studies show that the five-co-ordinate d6 cations, which are stereochemically non-rigid at room temperature, possess a trigonal-bipyramidal geometry with the halide or hydride in an equatorial position.The X-ray crystal structure of PF6 has been determined: the crystals are monoclinic, space group P2(1)/c, with a = 14.614(3), b = 14.625(3), c = 26.196(3) Angstroem, β = 100.41(1) degree, and Z = 4; final R factor 0.052 for 3219 observed reflections.The ruthenium cation has an approximate trigonal-bipyramidal geometry, with the bidentate dcpe ligands bridging axial and equatorial positions.This is the first five-co-ordinate complex of ruthenium(II) stucturally characterized as trigonal bipyramidal.According to their co-ordinatively unsaturated nature, the complexes (1+) react with L (L = CO or MeCN) to form the six-co-ordinate (1+), whose stereochemistry and dynamic behaviour were studied by 31P n.m.r. spectroscopy.The influence of the steric properties of the diphosphine on the formation of the (1+) species is discussed, and a dominant role for steric effects is suggested.
