Charge‐assisted hydrogen bonding in three diaminobenzene salts

Hydrogen‐bonding interactions play an important role in the rational design of crystal systems with desirable architectures. The crystal structures of benzene‐1,2‐diaminium sulfate sesquihydrate, C6H20N22+·SO42−·1.5H2O, (1), benzene‐1,3‐diaminium tetrachloridozincate(II), (C6H20N2)[ZnCl4], (3), and 3‐aminoanilinium perchlorate, C6H9N2+·ClO4−, (4), are reported. Hydrated salt (1) is a polymorph (space group C2/c) of a previously reported [Anderson et al. (2011). Cryst. Growth Des.11, 4904–4919] crystalline modification of salt (2) (space group P21/c). The contents of the asymmetric unit of (2) are twice that of (1). In each, the extended structures exhibit hydrogen bonds, resulting in chains of ions and hydrogen‐bonded rings with an R44(8) motif involving water molecules. Hirshfeld surface analysis shows that a significant difference between the two is the degree of C…C interaction. Salt (3) exhibits an extended structure having hydrogen‐bonded rings and parallel benzene rings, with a centroid‐to‐centroid separation of 3.860 (2) Å. Salt (4) displays a three‐dimensional superstructure that results from linked planes of ions joined by an extensive hydrogen‐bonding network involving N—H…O, N—H…N and C—H…π interactions. The cation–anion and N—H…N interaction energies in (4), determined using density functional theory (DFT), show significantly stronger aminium–perchlorate than amine–perchlorate interactions. The crystal structures of three protonated benzenediamine salts with sulfate, perchlorate, and tetrachoridozincate(II) counter‐ions are reported. The sulfate salt is a second crystalline modification of a previously reported compound. Hydrogen‐bonding interactions are explored using Hirshfeld surface analysis and DFT calculations.