ISSN:
1572-8951
Keywords:
Narrow-band high-spin heteronuclear polymers
;
nature of spin-exchange interaction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract It is shown that the group of π-conjugated, nonclassical (non-Kekulé) homonuclear, alternative organic polyradicals and polymers with degenerate NBMOs can be essentially extended to a large class of heterocyclic analogues having a set of degenerate MOs. The presence of a set of degenerate MOs (DMOs) results from the molecular topology of the system. The conditions of occurrence of DMOs are determined by the generalized Coulson-Rushbrooke-Longuet-Higgins theorem. The character of spin-exchange interaction of π-electrons in the half-filled band (HFB) of a large group of model polymers, analogues of poly(meta-anilines), has been investigated. It is shown that the main component of the ferromagnetic exchange interaction is the potential (Coulomb) exchange and a smaller contribution of the indirect exchange among the HFB electrons via the delocalized π-electrons in the occupied bands. The theoretical method used, which predicts the existence of a set of DMOs, may serve as a guiding principle in the design of narrow-band, high-spin organic polymers in which cooperative magnetic phenomena can arise.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01019468
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