Hydrogen-bonded benzimidazole-based tert-butylnitroxides

the solid state magnetic properties or a series of tert-butylnitroxides are compared: benzimidazole-2-tert-butylnitroxide (BImtBN), 4-(1H-benzimidazol -2-yl-phenyl-tert-butyl-nitroxide (BImPhtBN), 5(6)-chloro-BImtBN, and 5,6-d imethyl-BImtBN, (1-4, respectively). The series shows decreasing crystallog raphic unit cell complexity and increasing simplicity of magnetic behavior: 1-2 show magnetic behavior that has a good fit to a 2D simple planar Heise nberg: AFM model, and 3-4 show Bleaney-Bowers dimeric AFM exchange behavior . Hydrogen bonding in 3-4 appears to play a crystallographic assembly rathe r than an electronic exchange-role in the magnetic behavior of these system s. (C) 2001 Elsevier Science Ltd. All rights reserved.