Synthesis, crystal structure and spectroscopic investigations on organic complex salt and its interaction with bovine serum albumin

A new organic complex salt based on chlorogenic acid with 1,10-phenanthroline has been synthesized and characterized. The complex adopts 1:1 stoichiometry in the solid state. The proton transfer occurs from the carboxyl oxygen to the aromatic nitrogen atom to form the salt. The Hphen molecule individually occupies the pseudo-tetragonum that is formed with chlorogenic acid. The self-assembly of the compound in solid state is caused by a hydrogen-bonding interaction. The interaction of the organic complex salt with bovine serum albumin molecules has been studied by fluorescence spectroscopy. The bimolecular quenching constant, apparent quenching constant and number of binding sites have been obtained by fluorescence quenching and the binding distance calculated according to Foster's non-radioactive energy transfer theory. The corresponding thermodynamic parameters Delta H, Delta G and Delta S have also been calculated. The conformational changes of BSA have been observed from synchronous fluorescence spectra.