2-(4,5,6,7-Tetrafluorobenzimidazol-2-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1- H-imidazole-3-oxide-1-oxyl, A Hydrogen-Bonded Organic Quasi-1D Ferromagnet

• DOI: 10.1021/ja074211g
• Publication Date: 2007-12-11T09:00:33Z
• Authors: Hidenori Murata; Yuji Miyazaki; Akira Inaba; Armando Paduan-Filho; Valdir Bindilatti; Nei Fernandes Oli...; Zeynep Delen; Paul M. Lahti
• Keywords: Exchange interaction

The title radical (F4BImNN) is a stable nitronylnitroxide that forms hydrogen-bonded NH... ON chains in the solid state. assemble F4BImNN molecules to form stacked contacts between groups, geometry expected exhibit ferromagnetic (FM) exchange based on spin polarization (SP) models. experimental magnetic susceptibility of confirms expectation, showing 1-D Heisenberg chain FM behavior over 1.8-300 K with an intrachain constant Jchain/k = +22 K. At lower temperatures, ac and variable field heat capacity measurements show acts as quasi-1-D ferromagnet. dominant interaction attributable overlap orbitals within chains, consistent SP model expectations. appear be antiferromagnetically coupled, giving cusps zero at temperatures. results indicate sample orders magnetically about 0.7 ordering cusp shifts temperatures external increases, forming bulk antiferromagnetic phase below Néel temperature TN(0) 0.72 K, critical Hc approximately 1800 Oe. interchain estimated zJ/k congruent (-)0.1