ENYLPHOSPHINO)ETHANE)(ETA(3)-1-ARYLALLYL)PALLADIUM TETRAFLUOROBORATES- DISTRIBUTION OF THE POSITIVE CHARGE-DENSITY BY CORRELATION OF NMR CHEMICAL-SHIFTS WITH HAMMETT SUBSTITUENT CONSTANTS

C-13 NMR differences of chemical shifts (delta(X) - delta(H)) of allyl carbon atoms in a series of phino)ethane)(eta(3)-1-(4-X-phenyl)allyl) palladium tetrafluoroborates, X ranging from NO2 to OMe, correlate ver y well (r > 0.994) with sigma Hammett constants. However, P-31 NMR dif ferences of the ligand cis and traits phosphorus atoms correlate well with sigma and with sigma(+), respectively. These data indicate that t he positive charge density of the cation is localized mainly in the P- Pd-P region.