An infrared study of hydrogen bond stability in benzoic acid–trans­1,2­bis(4­pyridyl)ethylene complexes in the solid state and the implications for the design of supramolecular polymers

Derivatives of benzoic acid were complexed with trans-1,2-bis(4-pyridyl)ethylene. Infrared spectroscopy was used to confirm complexation and a correlation was found between the value of ν-C.dbd;O for the complex in the solid state and the pK a of the benzoic acid derivative. The stabilities of the hydrogen bonds in the complexes were investigated by temperature dependent infrared spectroscopy. It was found that all of the complexes behaved in a similar way, the hydrogen bonds remained intact until the melting point of the complex was reached. The implications for the design of supramolecular polymers are discussed.