Abstract

AM1 STUDY ON ELECTRONIC STRUCTURE AND CONFORMATIONS OF LACTIM-ENOL FORM OF METHICILLIN

Shabana Sultana, Bojja Rajeshwar Rao and Cherkupally Sanjeeva Reddy*

Abstract

The geometry, conformation and electronic structure of methicillin lactim-enol form have been optimized and calculated in the gas phase usually considering an isolated molecule surrounded by vacuum by semi-empirical molecular orbital AM1 method. In this connection, the protonation at nitrogen atoms of methicillin lactim-enol form has been studied. Further, the heats of formation (ΔHf o), dipole moment (μ), ionization potential (IP), full atomic charges, electronic excitation energies and energies of frontier molecular orbitals (EHOMO and ELUMO) have been performed and discussed. The conformational analyses of mono- and di-protonated methicillin lactim-enol form and their stable conformations have also been performed.

Keywords: AM1, lactim-enol form, methicillin, induction effect, frontier molecular orbital.