Mn(II)/Co(II)-based metal-organic frameworks assembled by 5,5'-(1,4-xylylenediamino) diisophthalic acid and various nitrogen-containing ligands for photocatalytic and magnetic properties

Abstract

Three novel Mn(II)/Co(II)-based 3D metal-organic frameworks (MOFs), namely {[Mn2(L)(tib)(H2O)]·3DMA·4H2O}n (1), {[Co2(L)(bipd)2]·3H2O}n (2) and {[Co(L)0.5(bimb)]·3H2O·0.5O2}n (3) (H4L ​= ​5,5'-(1,4-xylylenediamino) diisophthalic acid, tib ​= ​1,3,5-tris(1-imidazolyl)benzene, bipd ​= ​3,5-bis(1-imidazoly)pyridine, and bimb ​= ​1,4-bis(lmidazol)-butane), have been successfully synthesized using the mixed-ligand as functionalized organic linker. The structural characterization revealed that both MOFs 1 and 2 exhibited an unprecedented 4-nodal 3D framework that enriching crystal engineering, while MOF 3 featured a 2-nodal three-interpenetrating bbf topology framework with a Schläfli symbol of (64·82)(66)2. The title MOFs have been exploited as photocatalysts for degradation of methylene blue (MB), methyl violet (MV) and malachite green (MG). The photocatalytic results demonstrated that MOFs 2 and 3 exhibited efficient photocatalytic abilities to degrade the three aromatic dyes under UV irradiation. The possible catalytic mechanism was also explored and discussed in detail. Moreover, the variable-temperature magnetic analyses indicated that MOFs 1–3 exhibited weak antiferromagnetic behavior between Mn(II)/Co(II) ions.