title: Structural and electronic properties of 4H-cyclopenta[2,1-b,3;4-b']dithiophene S-oxide (BTO) derivatives with an S, S=O, O, SiH2, or BH2 bridge: semi-empirical and DFT study.
abstract: In this paper, we theoretically studied the geometries, stabilities, and the electronic and thermodynamic properties of 4H-cyclopenta[2,1-b,3;4-b']dithiopene S-oxide derivatives (BTO-X, with X = BH(2), SiH(2), S, S=O, or O) using semi-empirical methods, ab initio methods, and density functional theory. The geometries and thermodynamic parameters calculated by PM3 were in good agreement with those calculated with B3LYP/6-31 G*. The band gap calculated using B3LYP/6-31 G* ranged from 3.94 eV (BTO-O) to 3.16 eV (BTO-B). The absorption λ(max) calculated using B3LYP/6-31 G* was shifted to longer wavelengths when X = BH(2), SiH(2), or S=O (due to their electron-withdrawing effects) and to shorter wavelengths for BTO-S and BTO-O as compared to the λ(max) for the thiophene S-oxide (2TO) dimer. The changes in ΔH°, ΔS°, and ΔG° calculated using both semi-empirical and DFT methods were quite similar.
authors: Department of Pure and Applied Chemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria. semireban@yahoo.com
authors: Semire
authors: S
authors: Banjo
authors: Odunola Olusegun
authors: OO
authors: Ayobami
authors: Adejoro Isaiah
authors: AI
authors: Ajibade
mesh_terms: D001880:Boranes / Q000737:chemistry*; D003198:Computer Simulation; D003499:Cyclic S-Oxides / Q000737:chemistry*; D003517:Cyclopentanes / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D012821:Silanes / Q000737:chemistry*; D013816:Thermodynamics; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D001880:Boranes; D003499:Cyclic S-Oxides; D003517:Cyclopentanes; D012821:Silanes; D013876:Thiophenes