Theoretical studies on thiabenzene and its fused derivatives: DFT and ab initio computations

The molecular structures of thiabenzene ( 1 ), 1‐thianaphthalene ( 2 ), 2‐thianaphthalene ( 3 ), and 9‐thiaanthracene ( 4 ) are studied using HF and DFT methods with 6‐31+G* basis set. The nonplanar boat conformers of 1–4 , with 6π‐electrons in their heterocyclic ring, appear more stable than the corresponding planar conformers with 8π‐electrons in the ring. This study focuses on the stability, the ylide character, the inversion barrier energy of sulfur atoms, and the conformational flexibility of the ring in 1–4 . © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:376–381, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20214