Crystal structure of 4,4′-(disulfanediyl)dibutanoic acid–4,4′-bipyridine (1/1)

A distinctive feature of the crystal structure is the geometry of the dtba moiety, which appears to be stretched and acts as an hydrogen-bonding connector, forming linear chains along [-211] with the 4,4′-bpy moiety by way of O—H...N hydrogen bonds and C—H...O interactions. The influence of the mol­ecular shape on the hydrogen-bonding pattern is analysed by comparing the title compound and two other 4,4′-bpy co-crystals, showing the way in which this correlates with the packing arrangement.

Crystal structure of zwitterionic 4-(ammonio­methyl)­benzoate: a simple mol­ecule giving rise to a complex supra­molecular structure

The asymmetric unit consists of an isolated 4-(ammonio­meth­yl)benzoate zwitterion derived from 4-amino­methyl­benzoic acid through the migration of the acidic proton, together with a solvate water that is disordered over three sites. In the crystal structure, N—H...O hydrogen bonds together with π–π stacking of the benzene rings result in a strongly linked, compact three-dimensional structure.