Hydrogen bond controlled aggregation of guanidinium-carboxylate derivatives in the solid state

In this paper, we report the synthesis and aggregation properties of new self-complementary organic molecules containing guanidinium and carboxylate groups. The crystal structures of the guanidinium carboxylates showed linear bidentate hydrogen bonding between the guanidinium and the carboxylate groups. In the case of phenyl derivative 7, steric factors force a non-planar geometry for the hydrogen bonding subunit. Substitution of the phenyl by a pyridine leads to the formation of an intramolecular hydrogen bond and a planar conformation for the subunit. As a result, the simple intramolecularly hydrogen bonded molecule maintains a rigid control of binding group disposition in a manner similar to more complex multiple fused ring systems. (C) 2002 Elsevier Science Ltd. All rights reserved.