ELECTRONIC-STRUCTURE OF ARYLPHOSPHINE AND ALKYLPHOSPHINE

The electronic structure of tertiary arylphosphines and methylphosphin es are explored, using nb initio calculations and a detailed analysis of properties based on the electron distribution rho(r). The compariso n concentrates on the topology of rho and del(2) rho in the vicinity o f the phosphorus atom, and the integrated atomic properties (energies, multipole moments) of this atom. Some trends are revealed which are c onsistent with the known relative basicities of these compounds, where as others are unexpected. In particular (i) neither methyl nor aryl su bstituents substantially alter the charge on phosphorus, (ii) and the phosphorus-phenyl P-C bond of triarylphosphines, phenylphosphabicyclo[ 3.3.1]nonane and its [4.2.1] analogue indicate a significant conjugati ve effect, unlike in phenyl or pyridylphosphine.