AM1 study on the conformations and electronic properties of phenethicillin

Abstract

The geometry, conformation and electronic structure of phenethicillin have been optimized and calculated in the gas phase, usually considering an isolated molecule surrounded in a vacuum by using semi-empirical molecular orbital AM1 method. Further, the mechanism of protonation in phenethicillin 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), ionization potential (IP), full atomic charges and energies of frontier molecular orbitals (E_HOMO and E_LUMO) have been performed and discussed. The conformational analyses of mono- and di-protonated species have also been performed for stable conformations.