Charge transfer complexes of lanthanide 3,5-dinitrobenzoates and 1,2-phenylenediamine

Crystallization of lanthanide 3,5-dinitrobenzoates from MeCN-DMSO media in the presence of o-phenylenediamine (PDA) brings about the complexes of two types, the binuclear complexes built of the single molecules [Ln(2)(O2CC6H3(NO2)(2))(6)(PDA)(2)(DMSO)(2)] and the supramolecular polymers [Ln(2)(O2CC6H3(NO2)(2))(6)DMSO4]center dot PDA center dot 4MeCN. In both types of complexes, charge transfer (CT) between PDA molecules and 3,5-dinitrobenzoate fragments takes place; in the first case it is intramolecular, in the second case the binuclear fragments are united into supramolecular chains due to CT effect. Compounds of different types are often formed simultaneously; the complexes of the first type were isolated in pure form and studied for Gd, Tb, and Ho, while the complexes of the second type were obtained for Dy and Er. The charge transfer in the complexes was characterized by reflectance spectra; according to EPR study, it is too weak to make any paramagnetic contribution. (C) 2020 Elsevier B.V. All rights reserved.