AM1 study of the electronic structure of zwitterions of Ampicillin

Abstract

The conformation and electronic structure of zwitterions of ampicillin have been optimized and calculated by semi-empirical molecular orbital AM1 method. The mechanism of formation of zwitterions of Ampicillin has been studied by comparison of the different positions of net charges on nitrogen atoms in the molecule. In this connection, the heats of formation (∆H_f^o), dipole moment (µ), full atomic charges and energies of frontier molecular orbitals (E_HOMO and E_LUMO) have been performed and discussed. The effect of conformational changes and electronic properties of stable conformations have been determined.