TY - JOUR
T1 - Molecular orbital study on qu artet molecules with trigonal axis of symmetry
AU - Yoshizawa, Kazunari
AU - Hatanaka, Masashi
AU - Ito, Akihiro
AU - Tanaka, Kazuyoshi
AU - Yamabe, Tokio
N1 - Funding Information:
This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan. Numerical calculations were carried out at the Data Processing Center of Kyoto University.
PY - 1993/8/1
Y1 - 1993/8/1
N2 - The ESR spectrum of the randomly oriented cationic triradical of 1,3,5-tris(diphenylamino)benzene (TDAB) is shown to agree well with the theoretical prediction of a quartet (5 = 3/2) molecule. The electronic structures of non-Kekulé-type isoelectronic molecules 1,3,5-trimethylenebenzene (TMB) and 1,3,5-triaminobenzene trication (TAB3+) are discussed by means of the ab initio molecular orbital (MO) method in the unrestricted Hartree-Fock scheme. In TMB the quartet State with planar D3h geometry is predicted to lie 26.1 kcal/mol below the lowest doublet State with a planar C2V geometry in which one of the methylene groups has a longer C-C bridge bond connecting the phenyl ring. Moreover, in TAB3+ the quartet State with planar D3h also lies 16.9 kcal/mol below the lowest doublet State with an orthogonal geometry where one of the amino groups is twisted out of the molecular plane. These quartet ground states result from the nearly threefold-degenerate Orbitals consisting of the nonbonding MOs. In addition, the quartet-doublet Splitting energy of TDAB is investigated using the semiempirical AM1 method.
AB - The ESR spectrum of the randomly oriented cationic triradical of 1,3,5-tris(diphenylamino)benzene (TDAB) is shown to agree well with the theoretical prediction of a quartet (5 = 3/2) molecule. The electronic structures of non-Kekulé-type isoelectronic molecules 1,3,5-trimethylenebenzene (TMB) and 1,3,5-triaminobenzene trication (TAB3+) are discussed by means of the ab initio molecular orbital (MO) method in the unrestricted Hartree-Fock scheme. In TMB the quartet State with planar D3h geometry is predicted to lie 26.1 kcal/mol below the lowest doublet State with a planar C2V geometry in which one of the methylene groups has a longer C-C bridge bond connecting the phenyl ring. Moreover, in TAB3+ the quartet State with planar D3h also lies 16.9 kcal/mol below the lowest doublet State with an orthogonal geometry where one of the amino groups is twisted out of the molecular plane. These quartet ground states result from the nearly threefold-degenerate Orbitals consisting of the nonbonding MOs. In addition, the quartet-doublet Splitting energy of TDAB is investigated using the semiempirical AM1 method.
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U2 - 10.1080/10587259308035722
DO - 10.1080/10587259308035722
M3 - Article
AN - SCOPUS:84963330406
SN - 1058-725X
VL - 232
SP - 323
EP - 332
JO - Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals
JF - Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals
IS - 1
ER -