Conformational changes of the electrostatic potential of biphenyl: A theoretical study

Changes of the electrostatic potential (EP) of biphenyl upon internal rotation are studied by using B3LYP/6-311G(d,p) and MP2/6-311G(d,p) quantum calculations. The conformational variation of EP values at nuclei and spatial distributions of negative and positive domains allow to address reactivity and charge properties. The π-electron cloud is predicted to be favorably attacked by electrophiles at dihedrals larger than ∼l40° but below 90°. Substitution of hydrogens is favored in ortho at twisted conformations and in both meta and para at the coplanar geometry. Greater electron transfer and higher conductance are related with negative domains at the coplanar conformation.