Engineering the heterogeneous photocatalytic activity of crystalline decatungstate-based coordination polymers

Decatungstate (W10O324−, DT) is a metastable polyoxometalate anion which presents excellent photocatalytic ability. In order to stabilize the DT species, four decatungstate-based coordination polymer compounds with different DT coordination modes, namely [Cu2(3-bpo)2(H2O)2(DMSO)2][W10O32]·14H2O (1), [Cu2(3-bpo)2(DMSO)4][W10O32] (2), [Cu2(4,4′-bipy)4][H2W10O32] (3) and [Cu(4,4′-bipy)3(DMSO)(H2O)][TBA][HW10O32]·H2O (4) (DMSO = dimethyl sulfoxide, 3-bpo = 2,5-bis(3-pyridyl)-1,3,4-oxadiazole, 4,4′-bipy = 4,4′-bipyridine, TBA = tetrabutylammonium) were synthesized under controlled solvothermal conditions in the mixed solvent of DMSO and H2O. The heterogeneous photocatalytic activity of these four compounds in the degradation of rhodamine B was tested and the results show that they possess fairly high photocatalytic activity without leaching of DT during the reaction. The effect of the coordination modes of terminal oxygen (Ot) atoms in DT anions on the activity was investigated.