THEORETICAL APPROACHES TO MOLECULAR MAGNETISMS - THROUGH-BOND COUPLINGS BETWEEN TRIPLET CARBENES AND RELATED SPECIES

Ab initio post Hartree-Fock calculations were carried out for polyradi cal species formed by the through-bond couplings between organic radic al groups such as triplet carbenes. Detailed numerical results indicat e that the dynamic spin polarization (SP) rules proposed previously ar e applicable to qualitative predictions of the ground spin states of t hese species. On the other hand, the spin delocalization (SD) mechanis m is operative in the case of polyradicals linked with hetero atoms su ch as oxygen and nitrogen atoms. The ionized states of polycarbenes an d polyenes are also investigated in relation to possibilities of organ ic magnetic conductors. Computational results are compatible with expe rimental results available.