A THEORETICAL-STUDY OF THE CONFORMATIONS OF DIPHENYL ETHER, ITS ANION, AND ITS DIANION

The potential energy surfaces, of diphenyl ether (Ph2O), its anion and its dianion, were investigated using the AMI semiempirical description of the electronic wavefunction. Counterions with charges of +1 were used to approximate the solution electrostatic environments for the anion and dianion. The global minimum of the Ph2O potential energy surface is predicted to be a ''twisted'' conformation of the ''propeller'' form while the anion (Ph2O-) and dianion (Ph2O2-) are predicted to be of the ''skewed'' and ''gable'' forms, respectively. The relative energies of other critical points on the molecules' potential energy surfaces were calculated. The calculations reported herein indicate that the rings in Ph2O are nearly free rotors, but that Ph2O- may be a quasi-rigid structure and Ph2O2- is definitely rigid. Charge densities and some vibrational frequencies were calculated to characterize more accurately various conformations.