A {Ru(C6H6)}-Containing Isopolymolybdate with Good Photocatalytic Activity for Oxidative Coupling of Amines, and Proton Conduction Properties

We present a nonclassical {Ru(C6H6)}-containing isopolymolybdate Cs8K2Na2H4{[(C6H6)Ru]6Mo24O86}·35H2O (1) via one-pot reaction. The crystallographic characterization of compound 1 revealed that it contains an unusual {Mo24O86} cluster together with six {Ru(C6H6)} groups, having the largest number of {Ru(C6H6)} groups within the field of {Ru(C6H6)}-containing polyoxometalates. Results showed that compound 1 displayed excellent proton conductivity (9.8 × 10–3 S cm–1) at 90 °C and 95% relative humidity. Based on the calculation result of activation energy, which was more than 0.4 eV (1.47 eV), it was determined that the proton conduction process for compound 1 was in accordance with the Vehicle mechanism. More interestingly, compound 1 was exploited as a catalyst to achieve the heterogeneous oxidative coupling of amines and realized a high yield (98.9%) toward N-benzylidenebenzylamine under ambient temperature and visible light irradiation (>400 nm) and O2 atmosphere.