Quantum mechanical calculations on phenoxathiin and azaphenoxathiins heterocycles

The structure of phenoxathiin C6H4SOC6H4 as well as the effect of including electronegative nitrogen atoms in the arene rings of phenoxathiin have been studied using the ab initio method at the B3LYP/(6-31 + G) + d basis set level. Successive inclusion of nitrogen atoms resulted in an increase of the puckering angles of the azaphenoxathiin molecules. The calculations reproduced the observed bond length, bond angles and dihedral angles previously studied by X-ray measurements. The calculated barriers to planarity were found to correlate with the calculated puckering angels. The study predicts the configuration of several not yet synthesized azaphenoxathiin derivatives. \© 2005 Elsevier B.V. All rights reserved.