The abuse of antibiotics has caused global problems including critical environmental ecology impacts. Herein, four new metal–organic frameworks (MOFs) – {[Cd(HL)(bic)(H₂O)]·2H₂O}(1), {[Cd₃(L)₂(bbi)₂(H₂O)₂]·2H₂O}(2), [Cd₃(L)₂(bib)₂(H₂O)₂] (3) and [Cd₃(L)₂(idy)₂] (4), where bic = 3,6-bis(imidazol-1-yl)-9H-carbazole, bbi = 1,1′-(1,4-butanediyl)bis(imidazole), bib =1,4-bis(1-imidazoly)benzene and idy = 2-imidazol-1-ylpyridine – have been synthesized and fully characterized. 1 is a 1D chain with a large loop, stacked parallel to each other in 2D supramolecular layers by hydrogen-bonded and packing interactions. 2 and 3 are isostructural and show a 3D (3,8)-connected tfz-type network with (4³)₂(4⁶·6¹⁸·8⁴) topology. 4 has a 2D grid framework. The oxygen atom of the ether-bridging group acts as a Lewis base site, which improves the connection strength and allows the detection of 11 types of antibiotics through the fluorescence quenching effect. Among them, 2 exhibits sensitive and selective detection for nitrofural (NZF) (K_SV = 8.26 × 10³ M⁻¹ and LOD = 1.83 ppm). Moreover, the highly selective probe behavior towards NZF ions could be maintained even if there are other interfering antibiotics.

A new Cd(II) based metal–organic framework (MOF), having formula {(CH₃)₂NH₂)₆[Cd₅(L)₄]·H₂O·3DMF}_n (1), has been synthesized based on a rigid tetracarboxylate ligand of terphenyl-3,3′′,5,5′′-tetracarboxylic acid (H₄L). 1 shows a complicated 3D tetranodal 3,3,4,8-c network with uncoordinated –COO⁻ groups. The highly selective luminescent sensing of 2,4-dinitrophenol (2,4-DNP), 2,4,6-trinitrophenol (TNP) and ferric ions was studied for 1 through the alleviation in its fluorescence intensity. The detection limit of 2,4-DNP was found to be 0.84 ppm, which is 20 times higher than that of 1,3,5-trimethylbenzene, demonstrating greater and selective quenching ability. The possible mechanism associated with the decrease in fluorescence intensity of 1 in the presence of nitroaromatics (NACs) has been addressed by theoretical calculations. Furthermore, 1 displays excellent capacity to adsorb methylene blue (MB) with high selectivity, and it maintains an almost identical adsorption performance after being recycled five times.

The efficient removal of organic contaminants from wastewater is, nowadays, a prominent area of study due to its biological as well as environmental significance. Antibiotics are now found in wastewater because of their high use, which has become a source of aquatic pollution. These antibiotics have dangerous implications for people’s health. Hence, effective pharmaceutical removal from wastewater and contaminated water bodies, especially the removal of antibiotics, is of major interest to global research organizations. This is why it is necessary to investigate this class of toxic material in wastewater discharge. We synthesized three different coordination polymers (CPs) in the presence of various assistant carboxylate linkers, namely, [Zn(Hbtc)(dip)]_n (1), [Zn₄(1,2-bdc)₄(dip)₄]_n (2), and [Zn(1,4-bdc)(dip)]_n (3) (3,5-di(1H-imidazol-1-yl)pyridine = dip, 1,3,5-benzenetricarboxylic acid = H₃btc, 1,2-benzenedicarboxylic acid = 1,2-H₂bdc, and 1,4-benzendicarboxylic acid = 1,4-bdc). These CPs were characterized by using different techniques, including single-crystal X-ray diffraction. The structural studies demonstrated that in 2, there are four Zn(II) centers and both centers are in different coordination environments (Zn2 has distorted tetrahedral geometry, whereas Zn1, Zn3, and Zn4 have square pyramidal geometry). Hirshfeld surfaces analysis revealed that different types of intermolecular interactions (C⋯C, H⋯C, H⋯H, O⋯C, N⋯H, and O⋯H) are present in the synthesized CPs. We examined the different antibiotics, such as metronidazole (MDZ), nitrofurazone (NFZ), dimetridazole (DTZ), sulfasalazine(SLA), and oxytetracycline (OXY), degradation behaviors of the synthesized CPs, which showed remarkable degradation efficiency. 1 showed photocatalytic behavior toward the NFZ antibiotic in an aqueous media. This study also showed that these catalysts are stable and reusable under mild conditions.

Two new d ¹⁰ -based Cd( ii ) MOFs were synthesized and their photoluminescence sensing to selectively detect m -nitrophenol (MNP) and ability to decompose the organic dye methyl violet (MV) were explored.

Metal–organic frameworks (MOFs), a sub-class of well-known coordination polymers, are assorted multidimensional materials that can be employed as photocatalysts for the decomposition of aromatic dyes present in wastewater discharge. Herein, two new Cd(II) MOFs [Cd₇(L)₄(μ₂-OH)₂(H₂O)₄(bbi)₃] (1) and [Cd₃(L)₂(bbm)₂] (2) (H₃L = 3-(4-carboxyphenoxy)-5-methylbenzoic acid, bbi = 1,4-di(1H-imidazol-1-yl)butane and bmp = 1,3-bis(2-methylimidazolyl)pentane) have been synthesized and characterized. Single-crystal X-ray diffraction analysis reveals that 1 possesses a 3D (3,16)-connected pillar-bilayer network with a {3²·4}₂{3⁸·4⁵⁰·5³⁴·6²⁴·7⁴} topology and comprises [Cd₇(COO)₁₄] SBUs. Meanwhile, 2 exhibits a 2D (3,8)-connected framework with a {3·4²}₂{3⁴·4⁶·5⁶·6⁸·7³·8} topology comprising [Cd₃(COO)₆] SBUs. Both MOFs have been used as photocatalysts for the photodegradation of aromatic dyes, and experiments demonstrate that 1 and 2 exhibit 95.5% and 86.2% photodegradation of methyl violet (MV), respectively, in a time span of 100 min. Moreover, both MOFs offer better photodegradation of MV than other model dyes such as rhodamine B, methyl blue and methyl orange. Additionally, the effects of catalyst amount and dye concentration on dye degradation have been explored. Further, trapping experiments indicate that ˙OH and ˙O₂ ⁻ are the active species responsible for the degradation of MV in the presence of 1. Both MOFs could be recycled and used repeatedly as photocatalysts for the degradation of MV, which showcases their highly stable nature. Density of states plots and Hirshfeld surface analyses have been performed to address the plausible photocatalytic mechanistic pathways.