Syntheses, Structures, and Photocatalytic and Sonocatalytic Degradations of Methyl Blue of Cu(II) and Mn(II) Coordination Polymers Based on Tri(triazole) and Dicarboxylate Ligands

Cu(II) and Mn(II) coordination polymers [Cu(ttpa)(sub)]_n (<b>Cuttpa</b> or <b>1</b>) and {[Mn₂(ttpa)₂(nip)₂(H₂O)₂]·3H₂O}_n (<b>Mnttpa</b> or <b>2</b>) (ttpa = tris(4-(1,2,4-triazol-1-yl)phenyl)amine, H₂sub = suberic acid, nip = 5-nitroisophthalicate) were hydrothermally prepared and the structures were characterized. <b>Cuttpa</b> exhibited a 2D (4,4) network based on [Cu₂(COO)₄] dimers with upper and lower dangled ttpa ligands and a 2D → 3D polythreaded network. <b>Mnttpa</b> showed a 2D (4,4) network with dangled uncoordinated triazole rings from ttpa ligands and nitro groups from nip^2- ligands and a 2D → 3D polythreaded network. <i>E</i>_g data of <b>Cuttpa</b> and <b>Mnttpa</b> were 1.88 eV and 2.11 eV. <b>Cuttpa</b> and <b>Mnttpa</b> exhibited good catalytic activity for the decomposition of methyl blue (MB) under visible light and supersound irradiation. The decomposition mechanism using <b>Cuttpa</b> was explored. The holes (h⁺) and ^•OH hydroxyl radicals played the main roles, and the ^•O₂^- superoxide radicals played certain auxiliary roles in the decomposition of MB within the <b>Cuttpa</b> catalyst.