Molecular orbitals imidazole molecule

A reactivity index suitable for use in Equation 1 was calculated by using the simple molecular orbital techniques described by the Pullmans (14). Many indexes may be deduced from this type of procedure. The one that seemed to have the most significance for the correlation was the energy of the highest occupied molecular orbital (HOMO). This index is a relative measure of the ability of an electron to be transferred to an acceptor molecule. The calculations were performed on the substituted phenol in the imidazoline structure. This simplification was made since it could be assumed that any perturbation caused by the imidazole would be insulated from the rest of the molecule by the methylene group. 

Self-association of heterocycles containing NH groups (such as imidazoles, triazoles etc.) produces chains of planar molecules connected by N—H- -N hydrogen bonds. The effects of intermolecular hydrogen bonding on the molecular structures are confirmed also by ab initio molecular orbital calculations . 

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