Four structural diversity MOF-photocatalysts readily prepared for the degradation of the methyl violet dye under UV-visible light

Abstract

Four new metal–organic frameworks based on transition metals, namely [Mn₂(μ₂-H₂O)₂(H₂L)₂(CH₃CN)₂] (1), [Mn(L)_0.5(phen)·0.5H₂O] (2), [Co(H₂O)₂(L)_0.5(bip)·H₂O] (3) and [Co₂(L)(bb)₂·HbbBr] (4), where (H₄L = 5,5′-(1,4-phenylenebis(methyleneoxy))diisophthalic acid, bip = 3,5-bis(1-imidazoly)pyridine, phen = 1,10-phenanthroline, bb = 4,4′-bis(imidazolyl)biphenyl), have been successfully synthesized under solvothermal conditions. 1 showed a 2D layer featuring a polythreaded network with alternate left-and right-handed 2₁ helical chains. 2 possessed a 1D [Mn(H₂L)]_n chain that was further expanded into a 2D layer through O–H⋯O hydrogen bonds. 3 exhibited a 3D threefold interpenetrating network with a point symbol of (6⁴·8²)(6⁶)₂. 4 had a 3D 3-fold interpenetrated motif with 2-nodal 4,4-c connectivity. The photocatalytic results demonstrated that all of them could exhibit efficient photocatalytic abilities towards the degradation of methyl violet (MV) under UV irradiation. The mechanism of the photocatalytic performance was explored and discussed.