Long-range spin dependent delocalization promoted by the pseudo Jahn-Teller effect

摘要

Strong spin-dependent delocalization (double exchange) was previously demonstrated for the complexes, NN-Bridge-SQ-Co-III(py)(2)Cat-Bridge-NN (where NN = S = 1/2 nitronylnitroxide, Bridge = 1,4-phenylene and single bond, SQ = S = 1/2 orthobenzosemiquinone, Co-III = low-spin d(6) cobalt 3+, and Cat = diamagnetic catecholate). The mixed-valent S = 1/2 SQ-Co-III-Cat triad results in ferromagnetic alignment of localized (pinned) NN spins which are similar to 22 angstrom apart (Bridge = Ph). Herein, we report similar ferromagnetic coupling of localized verdazyl (Vdz) radical spins. The origin of the magnetic exchange results from a second order vibronic effect (pseudo Jahn-Teller effect) in [Vdz-diox-Ru(py)(2)-diox-Vdz](0), which possesses a diamagnetic [diox-Ru-diox](0) triad by virtue of strong antiferromagnetic SQ-Ru-III exchange. Published under license by AIP Publishing.