19536-79-9Relevant articles and documents
Synthesis of Hydridotrifluoromethyl Complexes of Platinum(II). A Spectroscopic Investigation of the trans and cis Influence of Ligands in Hydridoplatinum(II) Compounds
Michelin, Rino A.,Ross, Renzo
, p. 1149 - 1160 (2007/10/02)
The starting complex trans- is prepared from trans- by treatment of the derived labile solvento cationic species trans-BF4 (solv = acetone or CH2Cl2) with NaBH4 in EtOH at 0 dec C.The hydridotriflouromethyl complexes trans- are obtained by reaction of trans-PtH(CF3)(PPh3)2> with 2 equivalents of phosphine, L, in n-heptane at room temperature.Similar exchange reactions between trans- and equivalent amounts of diphosphine, L-L = cis-Ph2PCH=CHPPh2, Ph2PCH2CH2PPh2, Me2PCH2CH2PMe2, or Ph2PCH2CH2CH2PPh2, lead to the formation of the corresponding compounds.The hydridotrifluoromethyl complexes with L-L = cis-Ph2PCH=CHPPh2 and Ph2PCH2CH2PPh2 can be prepared also by reaction of the parent chloro derivatives with NaBH4 in EtOH at room temperature.The mixed isocyanide-phosphine complexes are obtained by reaction of trans- with a three-fold excess of RNC in n-heptane at room temperature.All the hydridotrilfluoromethyl complexes are air-stable in the solid state and in solution.They were characterized by elemental analyses and i.r., (1)H, (19)F, and (31)P n.m.r. spectra.The data obtained for υ(PtH) and (1)J(PtH) in trans- have been used to compare the trans influence of CF3(1-) with other ? carbon donors, R, in trans- derivatives.The n.m.r.-based trans influence order is CF3(1-) > C6H5(1-) > C6H9(1-) > CH2CH2CN(1-) > CH2CH2CH2CN(1-) > CH3(1-) > CH2CN(1-) > Cl(1-), whereas the i.r.-based trans influence order is C6H9(1-) > CH2CH2CH2CN(1-) > C6H5(1-) = CH3(1-) > CF3(1-) > Cl(1-).The opposite position of CF3(1-) in the two series of trans influence has been explained by the different mechanism operating on (1)J(PtH) and υ(PtH).The first depends predominantly on the s character of the platinum hydrid orbital used in the Pt-H bond, while the second is sensitive also to electrostatic effects induced by the electronegative fluorine atoms.The (1)J(PtP) data for the same series of complexes gives the following order of cis influence: Cl(1-) > CH2CN(1-) > CF3(1-) = CH3(1-) = C6H5(1-) = CH2CH2CN(1-) > CH2CH2CH2CN(1-).From the spectra of trans- (X = CF3 or Cl), the effects of replacing two PPh3 ligands in trans- by L on υ(PtH) and (1)J(PtH) were measured.With the assumption that the cis effects are additive, the i.r. and n.m.r. parameters were correlated with the electronic χ and steric θ parameters of the phosphine ligands.
