Dimeric supramolecular motifs of two carboxylate-guanidinium compounds

The structures of N-benzyl-N'-{6-[(4 carboxylatobenzyl)aminocarbonyl]-2-pyridylmethyl}guanidinium, C23H23N5O3, (I), and N-[2-(benzylaminocarbonyl)ethyl]-N'-{6-[(4-carboxylatobenzyl)aminocarbonyl]-2-pyridylmethyl}guanidinium monohydrate, C26H28N6O4·H2O, (II), both form three-dimensional supramolecular hydrogen-bonded networks based on a dimeric primary synthon involving carboxylate-guanidinium linkages. The differences in the geometries and hydrogen-bonding connectivities are driven by the additional methylpropionamide group and water of crystallization of (II