title: An AB initio investigation of molecules with a disulfide bond: (HS)2, (CH3S)2 and cystine.
abstract: ab initio Calculations at the Gaussian-70 STO-3G and 4-31G basis levels have been carried out for (HS)2 and (CH3S)2. Cystine was investigated at the STO-3G level. The STO-3G energy minimized geometry agrees well with experiments for (HS)2 and (CH3S)2. The barriers to internal rotation are predicted to be (at the 4.31G level): (HS)2, cis 8.5 kcal, trans 3.03 kcal; (CH3S)2, cis 18.47 kcal, trans 6.04 kcal.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D003553:Cystine; D004220:Disulfides; D006860:Hydrogen Bonding; D008968:Molecular Conformation
chemical_list: D004220:Disulfides; D003553:Cystine