Molecular Recognition of Imidazole-Based Drug Molecules by Cobalt(III)- and Zinc(II)-Coproporphyrins in Aqueous Media

The methods of ¹H NMR, spectrophotometric titration, mass spectrometry and elemental analysis are applied to determine the selective binding ability of Co(III)- and Zn(II)-coproporphyrins I towards a series of imidazole-based drug molecules with a wide spectrum of pharmacological activity (metronidazole, histamine, histidine, tinidazole, mercazolil, and pilocarpine) in phosphate buffer (pH 7.4) simulating the blood plasma environment. It is shown that in aqueous buffer media, Co(III)-coproporphyrin I, unlike Zn(II)-coproporphyrin I, binds two imidazole derivatives, and the stability of mono-axial Co-coproporphyrin imidazole complexes is two to three orders of magnitude higher than that of similar complexes of Zn-coproporphyrin I. The studied porphyrinates are found to have the highest binding ability to histamine and histidine due to the formation of two additional hydrogen bonds between the carboxyl groups of the porphyrinate side chains and the binding sites of the ligands in the case of histidine and a hydrogen bond between the amino group of the ligand and the carbonyl oxygen atom of the carboxyl group of the porphyrinate in the case of histamine. The structures of the resulting complexes are optimized by DFT quantum chemical calculations. The results of these studies may be of use in the design of biosensors, including those for the detection, control and verification of various veterinary drug residues in human food samples.

Recent advances in Ti-based MOFs in biomedical applications

Currently, metal-organic frameworks (MOFs), basically inorganic-organic hybrid materials, have gained tremendous attention due to their vast applications. MOFs have shown enormous applications in almost every research field. However, the area of designing MOF materials for their biological applications is still an emerging field that needs attention. Titanium-based metal-organic framework (Ti-MOF) materials are used in many research areas due to their structural advantages, such as small particle size and large effective surface area. On the other hand, they have also shown unique advantages such as good biocompatibility, excellent catalytic oxidation and photocatalytic properties and ease of functionalization. This study reviews the recent research progress on Ti-MOFs in therapeutic areas such as antibacterial, oncology, anti-inflammation, and bone injury, which will provide new directions for further research in this biomedical field. Therefore, this article will help scientists working in the particular field to enhance their understanding of Ti-based MOFs for functional biomedical applications.

Current status and prospects of metal-organic frameworks for bone therapy and bone repair

With the development of society, traumatic bone defects caused by accidents, diseases and surgeries have become common, eventually resulting in an increase in bone defects. The treatment of bone defects is characterized by a long period of treatment, high cost and uncontrollable outcomes. Also, it results in complications such as infection and bone discontinuity. Hence, due to this situation, the physical, mental and financial aspects of the patient are severely affected. What's more, such outcomes pose a challenge to orthopaedic surgeons. As a result, bone therapy and bone repair have become a hot topic of interest. In repairing bone defects, materials other than autogenous bone are still unable to provide good biocompatibility, osteogenesis, osteoconductivity and osteoinduction properties at the same time. In addition, the scarcity of autologous bone sources has forced the search for new autologous bone replacement materials. Metal organic frameworks (MOFs) are a new class of developed functional materials that have been widely used in the biomedical field during the recent years due to their porous nature, large specific surface area and diverse structures. With the progress in the investigation into bone treatment and repair, more and more investigators are using MOFs in bone therapy and bone repair. With these viewpoints, in the present perspective, the use of MOFs in bone therapy and bone repair has been summarized, and an insight into the future of MOFs in bone therapy and bone repair has been provided.

Efficient photodegradation of dyes by a new 3D Cd(II) MOF with rare fsh topology

Metal–organic frameworks (MOFs) can be regarded as 3D coordination polymers that adopt ordered porous structures and possess abundant active sites, which make them promising photocatalysts for the degradation of organic...

Coordination Polymers Based on Highly Emissive Ligands: Synthesis and Functional Properties

Coordination polymers are constructed from metal ions and bridging ligands, linking them into solid-state structures extending in one (1D), two (2D) or three dimensions (3D). Two- and three-dimensional coordination polymers with potential voids are often referred to as metal-organic frameworks (MOFs) or porous coordination polymers. Luminescence is an important property of coordination polymers, often playing a key role in their applications. Photophysical properties of the coordination polymers can be associated with intraligand, metal-centered, guest-centered, metal-to-ligand and ligand-to-metal electron transitions. In recent years, a rapid growth of publications devoted to luminescent or fluorescent coordination polymers can be observed. In this review the use of fluorescent ligands, namely, 4,4'-stilbenedicarboxylic acid, 1,3,4-oxadiazole, thiazole, 2,1,3-benzothiadiazole, terpyridine and carbazole derivatives, naphthalene diimides, 4,4',4''-nitrilotribenzoic acid, ruthenium(II) and iridium(III) complexes, boron-dipyrromethene (BODIPY) derivatives, porphyrins, for the construction of coordination polymers are surveyed. Applications of such coordination polymers based on their photophysical properties will be discussed. The review covers the literature published before April 2020.

Sensing organic analytes by metal–organic frameworks: a new way of considering the topic

In this review, our goal is comparison of advantageous and disadvantageous of MOFs about signal-transduction in different instrumental methods for detection of different categories of organic analytes.

A New 3D 10-Connected Cd(II) Based MOF With Mixed Ligands: A Dual Photoluminescent Sensor for Nitroaroamatics and Ferric Ion

The precise unification of functional groups and photoluminescence properties can give rise to MOFs that can offer diverse applications like selective detection of nitroaromatic compounds (NACs) which are considered to be an important ingredient of explosive as well as cation and anion sensing. Hence, a new 3D metal-organic framework (MOF) [Cd2(btc)(bib)(HCOO)(H2O)·H2O]n (1) has been synthesized using mixed ligand strategy by solvothermal reaction of cadmium acetate with two ligands viz. 1,3,5-benzenetricarboxylic acid (H3btc) and 1,4-bis(2-methyl-imidazol-1-yl)butane (bib). The MOF 1 possesses highly 10-connected network which is based on {Cd4(btc)2(bib)4} molecular building block. The studies showed that 1 could be taken as the fluorescent sensor for sensitive recognition of NACs, in particular 2,4,6-trinitrophenol (TNP) with notable quenching (K sv = 5.42 × 104 M-1) and LOD of 1.77 ppm. Additionally, 1 also displayed selective sensing for Fe3+ ions with K sv = 6.05 × 103 M- 1 and LOD = 1.56 ppm. Also, this dual sensor displayed excellent reusability toward the detection of TNP and Fe3+ ion. Theoretical calculations have been performed to propose the probable mechanism for the sensing luminescence intensity. Calculations indicated that because of the charge transfer and weak interaction that is operating between NACs and MOF, the weakening in the photoluminescence intensity resulted.

Syntheses and photocatalytic properties of three new d10-based coordination polymers: effects of metal centres and ancillary ligands

Three d¹⁰-based coordination polymers with three different nitrogen-based ancillary ligands have been synthesized and their photocatalytic properties were explored in the decomposition of methyl violet.

Topology, magnetism and dye adsorption properties of metal organic frameworks (MOFs) synthesized from bench chemicals

Two new MOFs (CuMOF-1 and CoMOF-2) are synthesized, characterized by spectral and magnetic studies and employed for selective dye adsorption properties.

A water-stable terbium-MOF sensor for the selective, sensitive, and recyclable detection of Al3+ and CO32− ions

A layered Tb-MOF structure exhibits high sensitivity, selectivity, and concurrently low limits of detection in relation to Al³⁺ and CO₃²⁻ ions.

Lanthanide-MOFs constructed from mixed dicarboxylate ligands as selective multi-responsive luminescent sensors

Five novel Ln-MOFs associated with the mixed ligands of 4-(pyridin-3-yloxy)-phthalic acid (H₂ppda) and terephthalic acid (H₂bdc), namely, [Ln(ppda)(bdc)_0.5(C₂H₅OH)(H₂O)]_n (Ln = Sm (1), Eu (2), Gd (3), Tb (4), and Dy (5)) were synthesized under the solvothermal conditions. Compounds 1-5 exhibit the isostructural 2D layered structures. The solid-state luminescence properties of compounds 1, 2, 4 and 5 were investigated in detail. It was found that compound 4 not only detected nitrobenzene derivatives-based explosives with high selectivity, sensitivity, and recyclability, but also served as an excellent selective sensing material for Fe³⁺ ion and Cr₂O₇^2- ion. In particular, it is worth noting that the detection limit of TNP can reach 3.0 × 10^-8 M. It was found that the free oxygen atoms of the ether bond, which function as the Lewis basic sites in Ln-MOFs, might interact with metal ions. In addition, the sensing mechanisms of 4 for different analytes were explored further.

Two Chemically Stable Cd(II) Polymers as Fluorescent Sensor and Photocatalyst for Aromatic Dyes

Two new 2D Cd(II)-based coordination polymers (CPs), viz. [Cd₂(H₂L)₂(2,2'-bipy)₂] (1) and [Cd(L)0.5(phen)·0.5H₂O] (2), have been constructed using ethylene glycol ether bridging tetracarboxylate ligand 5,5'(4,4'-phenylenebis(methyleneoxy)) diisophthalic acid (H₄L). Both CPs behaved as profound fluorescent sensor for Fe3+ ion and nitro-aromatics (NACs), specifically 2,4,6-trinitrophenol (TNP). The stability at elevated temperature and photocatalytic behaviors of both 1 and 2 for photo-decomposition of aromatic dyes have also been explored. An attempt has been made to explore the plausible mechanism related with the decrease in fluorescence intensity of 1 and 2 in presence of NACs using theoretical calculations. Additionally, the probable mechanism of photo catalysis by 1 and 2 to photo-degrade aromatic dyes has been explained using density of states (DOS) calculations.

Synthesis of zinc-carboxylate metal-organic frameworks for the removal of emerging drug contaminant (amodiaquine) from aqueous solution

We herein report the removal of amodiaquine, an emerging drug contaminant from aqueous solution using [Zn₂(fum)₂(bpy)] and [Zn₄O(bdc)₃] (fum=fumaric acid; bpy=4,4-bipyridine; bdc=benzene-1,4-dicarboxylate) metal-organic frameworks (MOFs) as adsorbents. The adsorbents were characterized by elemental analysis, Fourier transform infrared (FT-IR) spectroscopy, and powder X-ray diffraction (PXRD). Adsorption process for both adsorbents were found to follow the pseudo-first-order kinetics, and the adsorption equilibrium data fitted best into the Freundlich isotherm with the R² values of 0.973 and 0.993 obtained for [Zn₂(fum)₂(bpy)] and [Zn₄O(bdc)₃] respectively. The maximum adsorption capacities foramodiaquine in this study were found to be 0.478 and 47.62mg/g on the [Zn₂(fum)₂(bpy)] and [Zn₄O(bdc)₃] MOFs respectively, and were obtained at pH of 4.3 for both adsorbents. FT-IR spectroscopy analysis of the MOFs after the adsorption process showed the presence of the drug. The results of the study showed that the prepared MOFs could be used for the removal of amodiaquine from wastewater.