Hydrogen-Bonded Networks from Poly(dimethylamidinium) Cations and Polycarboxylate Anions

Two ditopic and one tetratopic dialkylamidinium-containing compounds were synthesized and their ability to form hydrogen-bonded networks or frameworks with polycarboxylate anions was studied. A series of 11 different networks were crystallized: in all cases, the dialkylamidinium group is in the E/Z conformation, which rules out the possibility of forming strong paired R2²(8) hydrogen bonding interactions. Nevertheless, a series of interesting networks were formed, several of which contain solvent-filled channels. It was found that many networks showed a tendency toward solvatomorphism with four forms of one network and three of another isolated under slightly different crystallization conditions. Interestingly, several networks contain partially protonated polycarboxylate anions, which form short antielectrostatic O–H···O^–hydrogen bonds between anions that direct network formation.