Predicting co-crystal structures of N-halide phthalimides with 3,5-dimethylpyridine.

Crystal structure prediction (CSP) calculations were carried out to examine potential formation of co-crystals between N-halide phthalimides (Cl, Br or I) and 3,5-dimethylpyridine (35DMP). The co-crystal structure of N-bromophthalimide (nbp) with 35DMP (nbp-35DMP) is known, and the generated co-crystal structure of rank 1 is identical to experimental structure (VELXES). For the unknown crystal structure of N-iodophthalimide (nip), structure of rank 1 is suggested as a likely co-crystal structure. On the other hand, our calculations suggest the improbability of co-crystal formation between ncp and 35DMP. The CSP findings indicate that strong N-X...N interactions consistent with similar experimental structures in the Cambridge Structural Database play a major role in crystal structures of the studied compounds.