Bis(trifluoromethyl)phosphane and bis(pentafluorophenyl)phosphane and their pentacarbonyl tungsten complexes: improved synthesis and an experimental and density functional study

The use of Bu(3)SnH and Me(3)SnH in the synthesis of HP(CF(3))(2) and HP(C(6)F(5))(2) from the corresponding bromides leads to a high-yield synthesis, which additionally provides these compounds in large quantities. The pentacarbonyl tungsten complexes W(CO)(5)PH(CF(3))(2)] and W(CO)(5)PH(C(6)F(5))(2)] were synthesized reacting the corresponding phosphanes with W(CO)(5)THF] and characterized by X-ray and elemental analysis as well as multinuclear NMR and mass spectroscopy. The vibrational analyses of HP(CF(3))(2) and HP(C(6)F(5))(2) and their tungsten pentacarbonyl complexes were achieved in combination with hybrid DFT calculations. The optimized structures of W(CO)(5)PH(CF(3))(2)] and W(CO)(5)PH(C(6)F(5))(2)] at the B3PW91 level of theory using a LanL2DZ basis and ECP at the tungsten atom and a 6-311G(3d,p) and 6-311G(d,p) basis set for the nonmetal atoms, respectively, yield an impressively good agreement between experimental and theoretical geometric parameters. An increased pi-acidity of HP(CF(3))(2) in comparison with HP(C(6)F(5))(2) and HPPh(2) is discussed in the context of vibrational analysis, X-ray structural investigations, and theoretical calculations.