Luminescent sensing and photocatalytic degradation properties of an uncommon (4,5,5)-connected 3D MOF based on 3,5-di(3′,5′-dicarboxylphenyl)benzoic acid

Abstract

An uncommon microporous metal–organic framework (MOF), {[Zn₅(L)₂(DMF)₂(μ₃-H₂O)]·2DMF} (1), was successfully constructed using a less exploited symmetrical pentacarboxylate ligand, 3,5-di(3′,5′-dicarboxylphenyl)benzoic acid (H₅L). The MOF 1 features a trinodal (4,5,5)-connected topology having a Schläfli symbol of (4²·6³·8)(4⁵·6⁵)₂(4⁶·6⁴) and is stable in air as well as in acidic/basic aqueous media at room temperature. The MOF 1 behaves as a luminescent sensor for the highly selective and sensitive detection of Fe³⁺, Fe²⁺, Cu²⁺ and Ag⁺ ions and o-nitrophenol (MNP), p-nitrophenol (PNP), 2,4-dinitrophenol (DNP), 2,4,6-trinitrophenol (TNP) and 4-nitrotoluene (4-NT). Furthermore, the photocatalytic properties of 1 for the degradation of Methyl violet (MV) and Rhodamine B (RhB) have been explored. The possible quenching of the emissions of 1 in the presence of nitroaromatics has been addressed by theoretical calculations and the photocatalytic activity of 1 against organic dyes has been addressed using density of states (DOS) calculations.