Two Ln-based metal–organic frameworks based on the 5-(1H-1,2,4-triazol-1-yl)-1,3-benzenedicarboxylic acid ligand: syntheses, structures, and photocatalytic properties

Two new metal–organic frameworks (MOFs) having the formula [Ln(2)(H(2)O)(3)(L)(3)·3H(2)O](n) (Ln = Sm for MOF-Sm and Tb for MOF-Tb) have been synthesized solvothermally by reacting LnCl(3)·6H(2)O with 5-(1H-1,2,4-triazol-1-yl)-1,3-benzenedicarboxylic acid (H(2)L) and characterized. Single crystal X-ray analyses for MOF-Sm and MOF-Tb revealed that both MOFs are isostructural and display a (6,8)-connected 3D structure with a point symbol of (3(5)·4(4)·6(6))(3(5)·4(6)·5(17)). The natures of weak interactions existing in both MOFs have been assessed using Hirshfeld surface analyses and fingerprint plots. The utility of MOF-Sm as a photocatalyst for the safe photodegradation of the model aromatic dye methyl violet (MV) is also checked. The photocatalysis results showed that MOF-Sm offers reasonable photocatalytic degradation of this dye. The plausible photocatalytic mechanism of MOF-Sm aided photocatalysis has been explained with the help of band gap calculations using density of states (DOS) and partial DOS plots.