The applicability of two types of transition-metal carbonyl complexes as appropriate candidates for computationally derived Tolman's ligand electronic parameters were examined with density functional theory (DFT) calculations employing the B97D3 functional. Both Pd(0)L2(CO) and HRh(I)L2(CO) complexes correlated well with the experimental Tolman Electronic Parameter scale. For direct comparison of the electronic effects of diphosphines with those of monophosphines, the palladium-containing system is recommended. The t r a n s influence of various phosphines did not show a major difference, but the decrease of the H-Rh-P angle from linear can cause a significant change.
Keywords: DFT; QTAIM; diphosphines; electronic parameters.