On the Design of Radical–Radical Cocrystals

Abstract

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]2[MBDTA]2 (4) [MBDTA=methyl benzodithiazolyl] and the 2:1 cocrystals [C6F5CNEEN]2[TEMPO] (E=S, 5; E=Se, 6). In 4 the two types of radical are linked via bifurcated inter‐dimer δ+S⋅⋅⋅Nδ− interactions whereas 5 and 6 exhibit a set of five‐centre δ+E⋅⋅⋅Oδ− contacts (E=S, Se).

Cocrystal Engineering: A Collaborative Strategy toward Functional Materials

“…Recently, cocrystal materials have generally exhibited attractive performance with advanced applications in various fields . However, as a new design strategy toward functional materials, to realize targeted design toward functional cocrystal materials, it not only requires the coassembly processes to be understood, but also needs to explore the functionality‐related principles.…”

Zero-, one-, two- and three-dimensional supramolecular architectures sustained by Se…O chalcogen bonding: A crystallographic survey

“…Firstly, solvates are described followed by co-crystals. The chemical structures of the 20 compounds covered in this section, 204 – 224 [118] , [233] , [234] , [235] , [236] , [237] , [238] , [239] , [240] , [241] , [242] , [243] , [244] , [245] are shown in Fig. 25 .…”

“…In the 1:2 co-crystal 217 [242] , each of the selenium atoms in the bi-nuclear molecule forms a Se … O(carbonyl) interaction to form a three-molecule aggregate, Fig. 28 c. Another bi-nuclear molecule where the selenium atoms are connected to each other within a five-membered ring, 218 [243] , forms a 2:1 co-crystal with a nitrogen-oxo-containing molecule; both species are radicals. The oxo atoms atom accepts four Se … O(oxo) interactions, one each from each of the selenium atoms of the two co-formers, Fig.…”

Robust S4⋅⋅⋅O Supramolecular Synthons: Structures of Radical‐Radical Cocrystals [p‐XC6F4CNSSN]2[TEMPO] (X=F, Cl, Br, I, CN)

“…Thermodynamic arguments to favor cocrystal formation through co-sublimation suggest that radicals with low enthalpies of sublimation (i. e., volatile) should favor cocrystal formation when combined with co-crystals which exhibit potentially robust supramolecular synthons which increase the lattice enthalpy of the cocrystal. [21] Previous work by Haynes and coworkers implemented the established aryl/fluoro-aryl π-stacking interaction to prepare several mixed DTDA dimers. [23,24] Previous work on DTDA radicals has shown the propensity for the disulfide bond to form strong strong δ + S 2 •••E δÀ interactions.…”

“…Recently, we communicated the ability of DTDA radicals to crystallize with 1,3,2-dithiazolyl (DTA) radicals forming an S 1e) and an S 1f). [21] These systems differ from previous approaches as it is the interaction between the radicals themselves rather than their substituents which drives cocrystal formation. In this paper, we identify the S…”