The pioneering role of metal-organic framework-5 in ever-growing contemporary applications - a review.

MOF-5 with a Zn(ii) cluster and terephthalic acid is a distinctive porous material among the metal-organic frameworks (MOFs), with unique physical, chemical and mechanical properties. MOF-5 based composites possess ample applications in modern chemistry. Huge surface area, suitable pore dimensions and scope of tunability make MOF-5 noteworthy in advanced materials. The extensive features of MOF-5 provided an opportunity for researchers to explore atomic/molecular scale materials. Various MOF-5 based composites have been designed with revamped properties appropriate to the application by altering and fabricating MOF-5 in situ or using a post-synthetic approach. Surface modification via the dispersion and impregnation of active substances into the pores of MOF-5 enhances its applicability. The boundless topologies and morphologies of MOF-5 combined with other chemical entities has provided opportunities in various fields, including catalysis, gas storage and sensors. The present review illuminates the leading role of MOF-5 and its composites in contemporary applications based on the current literature in heterogeneous catalysis, H2 and CO2 storage and sensors.

A Review on Metal-Organic Frameworks as Congenial Heterogeneous Catalysts for Potential Organic Transformations.

Metal-organic frameworks (MOFs) have emerged as versatile candidates of interest in heterogeneous catalysis. Recent research and developments with MOFs positively endorse their role as catalysts in generating invaluable organic compounds. To harness the full potential of MOFs in value-added organic transformation, a comprehensive look at how these materials are likely to involve in the catalytic processes is essential. Mainstays of MOFs such as metal nodes, linkers, encapsulation materials, and enveloped structures tend to produce capable catalytic active sites that offer solutions to reduce human efforts in developing new organic reactions. The main advantages of choosing MOFs as reusable catalysts are the flexible and robust skeleton, regular porosity, high pore volume, and accessible synthesis accompanied with cost-effectiveness. As hosts for active metals, sole MOFs, modified MOFs, and MOFs have made remarkable advances as solid catalysts. The extensive exploration of the MOFs possibly led to their fast adoption in fabricating new biological molecules such as pyridines, quinolines, quinazolinones, imines, and their derivatives. This review covers the varied MOFs and their catalytic properties in facilitating the selective formation of the product organic moieties and interprets MOF's property responsible for their elegant performance.

A Review on Recent Advances in Nitrogen-Containing Molecules and Their Biological Applications.

The analogs of nitrogen-based heterocycles occupy an exclusive position as a valuable source of therapeutic agents in medicinal chemistry. More than 75% of drugs approved by the FDA and currently available in the market are nitrogen-containing heterocyclic moieties. In the forthcoming decade, a much greater share of new nitrogen-based pharmaceuticals is anticipated. Many new nitrogen-based heterocycles have been designed. The number of novel N-heterocyclic moieties with significant physiological properties and promising applications in medicinal chemistry is ever-growing. In this review, we consolidate the recent advances on novel nitrogen-containing heterocycles and their distinct biological activities, reported over the past one year (2019 to early 2020). This review highlights the trends in the use of nitrogen-based moieties in drug design and the development of different potent and competent candidates against various diseases.

A review on novel composites of MWCNTs mediated semiconducting materials as photocatalysts in water treatment.

Many technologies were explored to eliminate the harmful pollutants entering water systems and to minimize their impact on environment. In general, photo-catalysis is one of the sustainable techniques with wider applications and semiconductors in particular were efficiently utilized in the photocatalytic degradation of pollutants. Semiconducting materials, such as TiO2, ZnO, BiO, CdS, and Ag3PO4 are frequently used as photo-catalysts due to their suggestible band gap and structural properties. The generation of reactive oxygen species such as hydroxyl and superoxide radicals is the crucial factor in degradation of pollutant molecules. The rapid recombination of photo-generated electron-hole pairs impacts on the efficacy of semiconductors as photo-catalysts. The integration of properties of multi-walled carbon nanotubes (MWCNTs) with semiconductors is considered as imperative alternative strategy to boast the photocatalytic efficiency. The combinative merits of composites of MWCNTs and various semiconductor materials give new vista for water treatment and environmental protection. This review describes the scope of different types of MWCNT and semiconductor composites as photo-catalysts and their structure-property relationships in oxidative degradation and mineralization of organic pollutants, in particular.

Our Contributions in Synthesis of Diverse Heterocyclic Scaffolds by Using Mixed Oxides as Heterogeneous Catalysts.

This personal account mainly introduces and reviews our recent contributions in developing different catalyst materials involving mixed oxides and their scope as renewable catalysts in multicomponent reactions to synthesize various novel heterocyclic scaffolds under green conditions. The application of various mixed oxides and their composites in the organic synthesis is emphasized through this review, in order to reveal the versatility, scope and importance of mixed oxides and their interactions during the reaction. We have also briefed the limitations of mixed oxides as catalysts, to put forward the broader prospective in the field.

A facile, efficient, and sustainable chitosan/CaHAp catalyst and one-pot synthesis of novel 2,6-diamino-pyran-3,5-dicarbonitriles.

A simple and versatile one-pot three-component synthetic protocol is devised for heterocycles, viz. 2,6-diamino-4-substituted-4H-pyran-3,5-dicarbonitrile derivatives, in short reaction times ([Formula: see text]30 min) at room temperature using ethanol as a solvent. This method involves the three-component reaction of malononitrile, substituted aldehydes, and cyanoacetamide catalyzed by chitosan-doped calcium hydroxyapatites (CS/CaHAps) giving good to excellent yields (86-96%). Twelve new pyran derivatives (4a-l) were synthesized and their structures were established and confirmed by different spectroscopic methods ([Formula: see text]H NMR, [Formula: see text]C NMR, [Formula: see text]N NMR, and HRMS). The heterogeneous catalyst, CS/CaHAp, was characterized by various instrumental techniques including XRD, TEM, SEM, and FT-IR and TGA spectroscopies. The catalyst was easily separable and reusable for up to six runs without any apparent loss of activity. The reported protocol has many benefits, such as ease of preparation, use of a green solvent, reduced reaction times, excellent product yields, and operational simplicity.

Nanostructured Samarium Doped Fluorapatites and Their Catalytic Activity towards Synthesis of 1,2,4-Triazoles.

An investigation was conducted into the influence of the amino acids as organic modifiers in the facile synthesis of metal incorporated fluorapatites (FAp) and their properties. The nanostructured Sm doped fluorapatites (Sm-FAp) were prepared by a co-precipitation method using four different amino acids, namely glutamic acid, aspartic acid, glycine and histidine. The materials were characterized by various techniques including X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), high resolution transmission electron microscopy (HR-TEM), N2-adsorption/desorption isotherm, temperature programmed desorption (TPD) and fluorescence spectrophotometry. Under similar conditions, Sm-FAp prepared using different amino acids exhibited distinctly different morphological structures, surface area and pore properties. Their activity as catalysts was assessed and Sm-FAp/Glycine displayed excellent efficiency in the synthesis of 1,2,4-triazole catalyzing the reaction between 2-nitrobenzaldehyde and thiosemicarbazide with exceptional selectivity and 98% yield in a short time interval (10 min). The study provides an insight into the role of organic modifiers as controllers of nucleation, growth and aggregation which significantly influence the nature and activity of the catalytic sites on Sm-FAp. Sm-FAp could also have potential as photoactive material.

Piperazine-1,4-diium bis-(2,4,5-tricarb-oxy-benzoate) dihydrate.

In the title hydrated salt, C4H12N2 (2+)·2C10H5O8 (-)·2H2O, the piperazinediium cation, lying about an inversion center, adopts a chair conformation. The benzene ring of the anion makes dihedral angles of 25.17 (8)° with the carboxyl-ate group and angles of 8.50 (7), 20.07 (7) and 80.86 (8)° with the three carb-oxy-lic acid groups. In the crystal, the cations, anions and water mol-ecules are connected by O-H⋯O and N-H⋯O hydrogen bonds into double layers parallel to (110).