P-31 NMR-STUDY OF PHOSPHINE MONOSUBSTITUTED GROUP VIB METAL-CARBONYLS

The 31P chemical shift and coupling constants are reported for a series of carbonyl compounds of the type LM(CO)5, with M = Cr, Mo, W, and L = a tertiary phosphine: (CH3)3P, (C2H5)3P, (C6H5)3P, (3-XC6H4)3P (with X = F, Cl) and (4-XC6H4)3P (with X = F, Cl, CH3). For the chromium carbonyls the PCl3, C6H5PCl2 and (C6H5)2PCl derivatives have also been studied. The theory of Ionin was used to explain the chemical shift. Where possible, the coordination chemical shift was interpreted in terms of σ and π bonding between P and M. These parameters were discussed by comparison with the corresponding phosphine-BCl3 adducts. JPW is shown to be mainly dependent on inductive effects and JPH and JPF to change upon complexation of the free phosphine, according to the rule of Bent. © 1979.