Quartet states of non-kekulé molecules 1,3,5-trimethylenebenzene and 1,3,5-triaminobenzene trication

✍ Scribed by Kazunari Yoshizawa; Masashi Hatanaka; Akihiro Ito; Kazuyoshi Tanaka; Tokio Yamabe

• Book ID: 103030897
• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 488 KB
• Volume: 202
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(93)90035-y

✦ Synopsis

The electronic structures ofnon-Kekule isoelectronic molecules 1,3,Wimethylenebenzene (TMB) and 1,3,5-triaminobenzene trication (TABa+) 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 Djb geometry is predicted to lie 26 kcal/mol below the lowest doublet state with a planar Clv geometry in which one of the methylene groups has a longer C-C bridge bond connecting the phenyl ring. Moreover, in TAB'+ the quartet state with planar Djh geometry also lies 17 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.