CONTROL OF MAGNETIC-INTERACTIONS IN POLYARYLMETHYL TRIPLET DIRADICALS USING STERIC HINDRANCE

Three polyarylmethyl triplet diradicals are prepared by oxidation of the corresponding carbodianions. Solid-state studies of the diradicals using SQUID show an onset of short-range ferromagnetic interactions at temperatures below 4 K for diradical 3(2.) and antifeffomagnetic interactions below 70 K for diradicals 2(2.) and 4(2.). The diradicals and the corresponding carbodianions in solution are characterized using ESR, NMR, and UV-vis spectroscopy, and voltammetry.