We have used an ab initio self-consistent field(SCF) molecular orbital approach toinvestigate the equilibrium geometry and relative stability of C4S4m- (m=0,1,2,3,4). We foundthat the geometry of anions studied from m...We have used an ab initio self-consistent field(SCF) molecular orbital approach toinvestigate the equilibrium geometry and relative stability of C4S4m- (m=0,1,2,3,4). We foundthat the geometry of anions studied from m=0 to m=4 changes from non-aromatic structure toaromatic structure and fmally anti-aromatic structure and that the relative stability decreases inthe order of: C4S4m- > C4S42- > C4S4 > C4S4 > C4S4.展开更多
In an attempt to assist the experimental findings, density functional theory (DFT) studies at the B3LYP/6-311+G(3df,2p) level on the structures, vibrational frequencies and relative stabilities of disulfides XSSY and ...In an attempt to assist the experimental findings, density functional theory (DFT) studies at the B3LYP/6-311+G(3df,2p) level on the structures, vibrational frequencies and relative stabilities of disulfides XSSY and their isomeric thiosulfoxide structures SSXY where X and Y are H, F, Cl, Br and I, have been reported in the present paper. The agreement with the available observed values experimentally is good. The calculated results suggest that the linear structures are more stable than their branched structures thermodynamically for all S2XY isomers. Thiosulfoxide difluoride SSF2, which is the only disulfide known to exist in two stable isomeric forms, is the most closest to its disulfide isomer energetically in all tautomers discussed in this paper. The activation energies for the unimolecular isomerization at room temperature were also predicted at the same level, and the calculated results indicated that the chain forms of XSSY are stable with respect to their corresponding branched forms kinetically. The intramolecular atom transfer rearrangement reaction are not likely processes because of the high potential barriers.展开更多
文摘We have used an ab initio self-consistent field(SCF) molecular orbital approach toinvestigate the equilibrium geometry and relative stability of C4S4m- (m=0,1,2,3,4). We foundthat the geometry of anions studied from m=0 to m=4 changes from non-aromatic structure toaromatic structure and fmally anti-aromatic structure and that the relative stability decreases inthe order of: C4S4m- > C4S42- > C4S4 > C4S4 > C4S4.
文摘In an attempt to assist the experimental findings, density functional theory (DFT) studies at the B3LYP/6-311+G(3df,2p) level on the structures, vibrational frequencies and relative stabilities of disulfides XSSY and their isomeric thiosulfoxide structures SSXY where X and Y are H, F, Cl, Br and I, have been reported in the present paper. The agreement with the available observed values experimentally is good. The calculated results suggest that the linear structures are more stable than their branched structures thermodynamically for all S2XY isomers. Thiosulfoxide difluoride SSF2, which is the only disulfide known to exist in two stable isomeric forms, is the most closest to its disulfide isomer energetically in all tautomers discussed in this paper. The activation energies for the unimolecular isomerization at room temperature were also predicted at the same level, and the calculated results indicated that the chain forms of XSSY are stable with respect to their corresponding branched forms kinetically. The intramolecular atom transfer rearrangement reaction are not likely processes because of the high potential barriers.
