Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.271, 183-194, 1995
New Charge-Transfer Complex-Based Organic Ferromagnets - Pyridinium-Substituted Imidazolin-1-Oxyl/Tetrafluorotetracyanoquinodimethanide or Hexacyanobutadienide Salts
The charge-transfer (CT) complexes of a series of 4,4,5,5-tetramethylimidazolin-1-oxyls substituted with 4-(N-alkylpyridinium) groups at the 2-position with two radical anions, tetrafluorotetracyanoquinodimethanide (TCNQF(4)(-.)) and hexacyanobutadienide (HCBD-.) were prepared and their magnetic properties were investigated in the temperature range of 5 to 300 K. Ferromagnetic interaction was observed for the three CT complexes. Furthermore, the magnetic measurement at lower temperatures than 5 K showed that these CT complexes exhibited a ferromagnetic phase transition between 0.4 and 0.55 K. Consequently, the present CT complexes make a group of another type of organic ferromagnets without any magnetic metal elements.