Two Ln-based metal-organic frameworks based on the 5-(1 H -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-(1 H -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.