Absorption and fluorescence of complexes of compounds of anthracene carboxylic acids with metal ions in liquid solutions

We have studied the absorption and fluorescent properties of complexes formed by compounds of anthracene-9-carboxylic acid with metal cations in dimethyl sulfoxide and ethanol. The composition and stability of these complexes has been determined. It is shown that when lanthanide ions are added (Ln³⁺) 21 complexes are formed predominantly, i.e., RCOO^– Ln^{3+ –}OOCR, while with Cd²⁺ the complexes are mainly 11, i.e., RCOO^– Cd²⁺. We have considered the principal mechanisms for the deactivation of excitation in complexes based on the RE ions (dipole-dipole energy transfer and electron transfer). The interactions were shown to be inner-sphere in character in the ion triplets, and outer-sphere in the ion pairs. The metal-ligand distance in the 21 complexes is estimated to be 0.5–0.6 nm.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 6, pp. 673–682, November–December, 1989.In conclusion the authors wish to thank A. S. Cherkasov for synthesizing and making available the ACA and for discussing the results of the investigation.