On the Design of Radical–Radical Cocrystals

Formation of radical–radical cocrystals is an important step towards the design of organic ferrimagnets. We describe a simple approach to generate radical–radical cocrystals through the identification and implementation of well‐defined supramolecular synthons which favor cocrystallization over phase separation. In the current paper we implement the structure‐directing interactions of the E?E bond (E=S, Se) of dithiadiazolyl (DTDA) and diselenadiazolyl (DSDA) radicals to form close contacts to electronegative groups. This is exemplified through the preparation and structural characterization of three sets of radical cocrystals; the 2:2 cocrystal PhCNSSN]₂MBDTA]₂ ( 4 ) MBDTA=methyl benzodithiazolyl] and the 2:1 cocrystals C₆F₅CNEEN]₂TEMPO] (E=S, 5 ; E=Se, 6 ). In 4 the two types of radical are linked via bifurcated inter‐dimer ^δ+S???N^δ? interactions whereas 5 and 6 exhibit a set of five‐centre ^δ+E???O^δ? contacts (E=S, Se).