Structural Diversity in 1,3-Bis(m‑cyanophenyl)urea

• Published in: Crystal growth & design Vol. 15; no. 5; pp. 2373 - 2379
• Main Authors: Capacci-Daniel, Christina A, Mohammadi, Cameron, Urbelis, Jessica H, Heyrana, Katrina, Khatri, Natasha M, Solomos, Marina A, Swift, Jennifer A
• Format: Journal Article
• Language: English
• Published: American Chemical Society 06.05.2015
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/acs.cgd.5b00168

Hydrogen bonding between 1,3-bis ureas is a commonly used motif in the assembly of supramolecular structures such as gels, capsules and crystals. The title compound, 1,3-bis­(m-cyanophenyl)­urea (mCyPU), has previously been shown to crystallize in both an anhydrous and monohydrate phase (α and H–I). An expanded search for polymorphs and cocrystals of mCyPU revealed a much greater diversity of solid forms including three additional polymorphs (β, δ, ε), a second hydrate (H–II) and two cocrystal phases with dimethyl sulfoxide and triphenylphosphine oxide. Analysis of the single crystal structures obtained in this study shows that the typical 1-dimensional H-bonding between 1,3-bis urea groups is disrupted by the presence of other H-bond acceptors including cyano, water, sulfoxide and phosphine oxide functionalities. Re-examination of α-mCyPU additionally showed both blade and plate-like morphologies could be obtained from different growth solvents, with crystals of the latter morphology exhibiting a grain boundary migration prior to melting.