Syntheses of a series of lanthanide metal–organic frameworks for efficient UV-light-driven dye degradation: experiment and simulation

Abstract

Three new Ln(III)-based metal–organic frameworks (MOFs), having general formula [Ln₂(L)₂(ox)(H₂O)₂]_n (Ln = Nd (1), Sm (2) and Eu (3)), have been synthesized using multifunctional triazole–carboxylate linker 5-(1H-1,2,4-triazol-1-yl)-1,3-benzenedicarboxylic acid (H₂L) and another dicarboxylate ligand oxalate (ox²⁻). The single crystal X-ray diffraction studies indicate that all three complexes are isostructural in nature and show unique 3,8-connected 3D networks with a point symbol of (4²·6)₂(3⁹·4¹²·5⁷) topology. All three MOFs possess various types of weak interactions in their framework and these have been assessed using Hirshfeld surface analyses and fingerprint plots. The Nd-based MOF 1 is also used as a photocatalyst for the degradation of organic dye methyl violet (MV) under UV light irradiation. The photocatalytic experiments revealed that MOF 1 offered good photocatalytic properties to photo-decompose MV. Additionally, the most potent radical responsible for the photodegradation of MV under UV irradiation was checked using different radical scavengers. The plausible photocatalytic mechanism of 1 aided photocatalysis is explained with the help of theoretical band gap calculations using density of states (DOS) and partial DOS plots.