Spectroscopic study of molecular associations between riboflavin and some (dihydro) β-carboline derivatives

Abstract The spectrophotometric and thermodynamic properties of molecular complexes of riboflavin (RFN) with some dihydro β-carboline derivatives have been investigated by using electronic absorption and fluorescence spectroscopic methods in aqueous solution. The molecular associations have been examined by means of eletronic absorption spectra, since in each, a new charge transfer-like band has been located, and also by observing the variation of the fluorescence emission of RFN on the solutions. The formation constants for the molecular complexes were determined from absorption data, using the Forster—Hammick—Wardley method. The quenching phenomenon observed in RFN fluorescence is related…