Molecular recognition of zinc porphyrin dimers to DABCO and corresponding thermodynamic study

A series of p/p type zinc porphyrin dimers covalently linked with a flexible chain are synthesized and characterized. The molecular recognition of zinc porphyrin dimers and corresponding monomer to rigid nitrogenous bidentate ligand DABCO (1, 4-diazobicyclo [ 2, 2, 2]octane) are described in detail by H-1 NMR and UV-Vis spectroscopy. DABCO can bind inside the cavities of porphyrin dimers and form a ternary sandwich complex as the length of the alkoxyl chain is long enough and their molar ratio is suitable. The thermodynamic parameters such as the equilibrium constants, stoichiometric numbers, and the corresponding enthalpies and entropies of the binding behavior are also obtained by UV-Vis spectroscopy.