Semiempirical and Ab Initio Electronic Structures and Geometrical Optimization of Recently Synthetized Cyclopentaphenanthrene derivatives

Abstract

It is well known that polycyclic aromatic hydrocarbons are a dangerous class of widespread environmental pollutants due to their persistance, tendency to accumulate, and mutagenic properties. Important studies which have appeared in the scientific literature since the 1980s have shown that there is an important correlation between the distortion from planarity of many of these molecules and their carcinogenic activity. In this article, the results of electronic distribution calculations for a homogeneous class of recently synthetized cyclopentaphenanthrene derivatives are reported. Calculations were performed at semiempirical and ab initio levels. At the former, all the molecular geometries were fully optimized. More accurate single-point Hartree-Fock-Self Consistent Field (HF-SCF) ab initio calculations were then performed on the resulting optimized structures. Results for some important geometrical parameters and electronic properties are also reported. The qualitative analysis of the molecular structures obtained from Parametric Method 3 (PM 3 ) geometrical full optimizations shows that molecular distortion does not seem to be associated with mutagenicity.