Europium-ytterbium bimetallic complex-based sensor for detecting DMSO impurities in DMSO-d6

We proposed a novel approach to the creation of a sensor to determine the DMSO impurity in DMSO-d6, based on europium-ytterbium bimetallic complex, which demonstrated the sensitivity up to 31 % per fraction of DMSO in solution. Theoretical model of the sensing system was proposed. It demonstrated that the sensitivity does not depend on the ratio of ytterbium and europium in the bimetallic complexes but depends on the number of molecules of coordinated DMSO upon complex partial dissociation and the rate of quenching by DMSO molecules. Based on this theory, mixed-ligand bimetallic complexes of europium and ytterbium (EuxYb1−x(dbm)3BPhen; Hdbm – dibenzoylmethane, BPhen – bathophenanthroline; х = 0.01, 0.03, 0.05, 0.07, and 0.1) were proposed for sensing applications, and were synthesized and studied for the first time. The ratio of the luminescence bands of ytterbium and europium ions in a solution of the coordination compound Eu0.1Yb0.9(dbm)3BPhen linearly depends on the ratio of the concentrations of solvents DMSO and DMSO-d6 in the range V(DMSO)/V(DMSO-d6) from 0 to 1, allowing to detect an impurity of DMSO in DMSO-d6. The sensitivity of the observed system increased with the decrease of the DMSO content and equaled to Sr=0.381LIR and reached 31 % per fraction of DMSO in solution. The obtained experimental data verified the provided analytical description of the sensing system.