ABSTRACT Study of the interelectronic exchange interaction in and between organic molecules is greatly important to the design of magnetic effects in molecular-based, materials. Intramolecular exchange may be systematically studied by connection of a given pair of spin-bearing units linked by various structural groups with different connectivities. Use of this strategy for linkage of phenylnitrene units readily allows electron resonance spectroscopy study of open-shell electronic states. Determination of electronic state multiplicities of dinitrenes in cryogenic matrix show agreement with parity-based qualitative expectations for alternant pi-systems. Development of less reactive models for high spin organic molecules of potentially practical use have involved polyphenoxyl systems. Methodology for photochemical production of phenoxyl radicals in rigid solid state media have been extended to nonconjugated polyradicals. The observation of antiferromagnetic intrachain through-space exchange for nonconjugted polyphenoxyl-based systems is similar to behavior of nominally conjugated polyradicals synthesized by other workers. Based on this finding, a major obstacle to practical design of organic ferromagnetic polymeric systems is optimization of exchange interactions affected by polymeric geometry and morphology, rather than connectivity.
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