AB-INITIO MO STUDY OF M-PHENYLENEDIAMINE AND 2,4-DIAMINO-1,3,5-TRIAZINE DICATION DIRADICALS

Ab initio MO calculations of m-phenylenediamine (1) and 2,4-diamino-1, 3,5-triazine (2) dication diradicals, which are the model molecules of two possible high-spin polymers (poly(m-aniline) and poly(imino-1,3,5 -triazinediyl) cation radicals), have been carried out with the 6-31G basis set at the ROHF, GVB and CASSCF levels. In accordance with qual itative MO considerations, the electronic structures of 1(2+) and 2(2) were quite different from each other. In the planar C-2v, geometry, the singlet-tripler splittings (Delta ES-T) of 1(2+) and 2(2+) were ca lculated to be 0.7 and 12.5 kcal/mol, respectively, at the CASPT2 leve l. m-1,3,5-triazinediyl is another effective ferromagnetic coupler for the aza-substituted systems.