Spin Frustration in Organic Radicals

Abstract

Spin frustration, resulted from geometric frustration and a systematical inability to satisfy all antiferromagnetic (AF) interactions between the unpaired spins simultaneously, is under spotlight for its importance in physics and materials science. Spin frustration is treated as structural basis of quantum spin liquid (QSL). Featuring flexible chemical structures, organic radical species exhibit great potential in building spin‐frustrated molecules and lattices. Until now, the reported examples of spin‐frustrated organic radical compounds include triradicals, tetrathiafulvalene (TTF) radicals and derivatives, [Pd(dmit)2] compounds (dmit = 1,3‐dithiol‐2‐thione‐4,5‐dithiolate), nitronyl nitroxides, fullerenes, polycyclic aromatic hydrocarbons (PAHs), and other heterocyclic compounds, where the spin frustration is generated intra‐ or intermolecularly. In this Minireview, we provide a brief summary for the reported radical compounds possess spin frustration. The related data, including magnetic exchange coupling parameters, spin models, frustration parameters, and crystal lattices, are summarized and discussed.

Towards molecular alloys: computational and experimental studies on (p-NCC6F4CNSeSeN)x(p-NCC6F4CNSSN)1−x

“…The Weiss constant gives an upper limit to the magnetic ordering temperature. However, magnetic ordering often occurs at temperatures well below | θ | due to phenomena such as spin frustration 41 or low dimensionality of the exchange interactions 42 which fails to propagate magnetic ordering through the lattice.…”