Room-Temperature Magnets Based on 1,3,5-Triazine-Linked Porous Organic Radical Frameworks

Obtaining room-temperature (RT) molecule-based magnets is a long-soughtafter goal in the materials community. However, so far, most of the reported magnets based on charge-transfer salts, pure organic radicals, and coordination polymers have shown low magnetic ordering temperatures. Herein, we propose an alternative approach for magnets by using covalently linked organic radical frameworks, in which neighboring radicals are ferromagnetically coupled. Stable hexacyanotrimethylenecyclopropanide radical anions ([CN6CP]M, M = K+ [1a], n-Bu4N+ [1b]) were found to undergo either thermal polymerization in the solid state at a relatively low temperature (300 degrees C) without the need for ZnCl2 (for 1a) or trifluoromethanesulfonic-acid-mediated polymerization at 60 degrees C (for 1b) to give 1,3,5-triazine-linked porous organic radical framework 2 or 3, respectively. The resulting material 2 exhibited spontaneous magnetization at RT with typical hysteresis of ferromagnets, and the ordering temperature was estimated to be 465 K, whereas the magnetic behavior of 3 is more like superparamagnetism.