Metal–organic frameworks based on a benzimidazole flexible tetracarboxylic acid: Selective luminescence sensing Fe³⁺, magnetic behaviors, DFT calculations, and Hirshfeld surface analyses

Abstract

Four novel metal–organic frameworks constructed from benzimidazole flexible tetracarboxylic acid ligand, 1‐(3,5‐dicarboxylbenzyl)‐1H‐benzimidazole‐5,6‐dicarboxylic acid (H4L), have been prepared by a solvothermal method in the presence of N‐donor ancillary ligands (1,10‐phen = 1,10‐phenanthroline monohydrate, 4,4′‐bibp = 1,4‐di[pyridine‐4‐yl]benzene), namely, [Co2(L)(H2O)3]n (1), {[Cd2(L)(1,10‐phen)(H2O)]·2H2O}n (2), {[Co4(L)2(4,4′‐bibp)2(H2O)7]·4H2O}n (3), and {[Ni4(L)2(4,4′‐bibp)2(H2O)7]·4H2O}n (4). Complexes 1 and 2 show a 3D supramolecular structure and crystallize in monoclinic space group P21/c. Complexes 3 and 4 are isomorphous and crystallize in monoclinic space group Pn, and the respective metals exhibit a similar coordination environment. The H4L ligand behaved in different coordinated modes in Complexes 1–4, namely, μ6‐η1:η1:η1:η0:η1:η1:η1:η1:η1 in 1, μ6‐η1:η1:η1:η1:η1:η1:η2:η1:η1 in 2, there are two coordination modes (μ5‐η0:η1:η1:η0:η1:η1:η1:η0:η1 and μ5‐η1:η1:η1:η0:η1:η1:η1:η0:η1) in 3 and 4. Furthermore, photoluminescence and magnetic properties have been studied. The results indicate that Complexes 3 and 4 show strong antiferromagnetic and ferromagnetic coupling through M–O–C–O–M interactions, respectively. In particular, Complex 2 can sensitively and selectively detect Fe3+ in aqueous systems, and the limit of detection (LOD) values of Fe3+ is ∼0.19 mM.

Novel zinc (II) and nickel (II) complexes of a quinazoline‐based ligand with an imidazole ring: Synthesis, spectroscopic property, antibacterial activities, time‐dependent density functional theory calculations and Hirshfeld surface analysis

“…Two pairs of intramolecular hydrogen bonds (C8-H8AÁÁÁO1, C21-H21AÁÁÁO3) formed a five-membered ring (Figure 1). Eleven intermolecular hydrogen bonds were connected by the nitrate anions and L. Moreover, Zn(1) and Zn(2) formed an infinite 1-D chains-like by C(12)-H (12)ÁÁÁCg(5), C(26)-H(26A)ÁÁÁCg (5) and C( 16)-H( 16)ÁÁÁCg (7) interlinked. It was remarkable that 1 exhibited 2-D layer, 3-D multi-layer supramolecular and Meter-shaped 3-D perspective structure (Figures 2 and 3).…”

“…Supramolecular chemistry involving significant transition metal complexes is of great interest to the crystal engineering community since their potential applications as optics materials, [1,2] catalysis, [3,4] molecular magnetic materials, [5,6] luminescent materials, [7] molecular sensors, [8] and so on, which have received a widespread attention especially in the last decade. Heterocyclic ligands containing quinazoline ring was used widely as special scaffolds of bioactive molecules and inorganic syntheses.…”

A comparative study of proton conduction between two new Cd(II) and Co(II) complexes and in vitro antibacterial study of the Cd(II) complex

“…The optimization of free H 4 L and the HOMO–LUMO (HOMO is the highest occupied molecular orbital and LUMO is the lowest unoccupied molecular orbital) energy bandgap calculation for H 4 L and complexes 1 and 2 were performed with the GAUSSIAN 09 [ 42,43 ] program at the B3LYP/Gen level (the 6‐31‐G basis set for C, H, O, and N and the LANL2DZ basis set for the metal atoms) to model the initial guess of the title complexes obtained from the X‐ray refinement data (CIF). To save computing time, the structures were not optimized in the calculations.…”

A 3,8-connected Cd(ii)-based metal–organic framework as an appropriate luminescent sensor for the antibiotic sulfasalazine

“…Metal–organic frameworks (MOFs) are a class of porous materials that consist of metal ions and rationally selected organic ligands and have shown excellent potential applications in many fields such as sensing, photocatalysis, heterogeneous catalysis, gas storage, and drug delivery. 13–25 As sensors, 26–32 this class of materials has successfully detected a range of analytes that include ions and small molecules using various sensing mechanisms, particularly electron/energy transfer.…”