Luminescent sensing and photocatalytic degradation in a new 3D Zn(II)-based highly luminescent metal−organic framework

The intelligent blending of intriguing functionalities in ligands and incorporation of spectroscopically silent metal cations can produce metal-organic frameworks (MOFs) with multifarious applications viz. selective and specific sensing of nitroaromatic compounds (NACs) an important constituent of explosives as well as photocatalytic properties. A new 3D Zn(II)-based metal-organic framework, [Zn4(μ2-OH)2(BDC)3(bip)2] (1) have been synthesized using a mixed ligand strategy using benzene-1,3-dicarboxylic acid (H2BDC) and 1,4-bis(2-methyl-imidazole-yl)-propane (bip) and zinc nitrate via hydrothermal reaction. The framework of 1 adopts a 5-connected 3D network with the Schlafli symbol {33.4.52.62.72}. The luminescent sensing investigation indicated that 1 can behave as a luminescent sensor for highly sensitive detection of nitroaromatics (NACs) especially against 2,4,6-trinitrophenol (TNP). The possible depletion in the photoluminescence intensity of 1 in presence of NACs have been addressed using theoretical calculations which indicated that charge transfer as well as the weak interaction between NACs and MOF may be responsible for the decline in the photoluminescence intensity. The MOF have been used as the photocatalyst for the decomposition of methyl violet (MV). Also, the mechanism for the photocatalysis have been addressed using density of states (DOS) calculations.