The energy and force field for the planar cis and trans conformers of thionformic acid have been calculated using the 4-31 G basis set, augmented by a complete set of d-functions on the sulfur atom, with full geometry optimization. Extensive comparisons are made between the changes in geometry and selected force constants in going from cis- (chain) to the trans- (ring) structures of thionformic, thiolformic and formic acid. These changes are discussed in terms of a hydrogen bonding type of interaction in the OH⋯S, SH⋯O and OH⋯O structural units respectively. Of the thioacid conformers, the trans-thiol is found to be the most stable; the trans-thion and cis-thiol both about 10 kJ mol-1 less stable; and the cis-thion the least stable by about 38 kJ mol-1.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physical and Theoretical Chemistry