A series of germanotungstate-based 3d-4f heterometallic compounds with visible-light induced photocatalytic, electrochemical and magnetic properties

A series of 3d-4f heterometallic germanotungstate dimers {[Cu(dap)(H2O)(3)][LnCu(3)(dap)(3) (OH)(3)(H2O)(2)(GeW11O39)]}center dot nH(2)O (Ln = Sm-III = 11 (1), Eu-III, n = 12 (2), Gd-III, n = 10 (3) and Tb-III, n = 13 (4); dap = 1, 2-diaminopropane) have been prepared under hydrothermal conditions and structurally characterized by IR, UV-Vis, XRD, and X-ray single-crystal diffraction. Compounds 1-4 are essentially isomorphic and display organic-inorganic hybrid dimeric structures consisting of [LnCu(3)(dap)(3)(OH)(3)(H2O)(GeW11O39)](2)(4-) with two supporting [Cu(dap)(H2O)(3)](2+) cations on both sides. The four compounds all exhibit the excellent photocatalytic activities to degradation of methylene blue (MB) and rhodamine-B (RhB) under visible light irradiation in the presence of H2O2. Additionally, 1-4 displays an apparent electrocatalytic activity for the reduction of hydrogen peroxide. The variable-temperature magnetic studies show that the magnetic behaviours of 1, 2 and 4 are dominated by antiferromagnetic coupling interactions, while that of 3 is ferromagnetic interactions coexist along with antiferromagnetic interactions. (C) 2019 Elsevier B.V. All rights reserved.