PREDICTION OF HYDROGEN-BOND BASICITY IN NITRILES FROM DIPOLE-MOMENTS, MESOMERIC EFFECTS AND ELECTROSTATIC POTENTIALS

Measured molecular dipole moments and theoretical percentages of mesomeric zwitterionic forms were used to calculate the attractive electrostatic potentials at short, V(s), medium, V(m), and long, V(l), distances, Values of an attraction power function Phi (H) = A + BV(s)V(m)V(l) was then deduced for 18 nitriles and cyanamide vinylogues or iminologues along the C = N direction. The satisfactory agreement observed between Phi (H) and the hydrogen bond basicity scale pK(HB) indicates that the method can be a useful tool for the prediction of hydrogen bonding, needing only simple calculations and allowing easy interpretation.