Base mediated synthesis of α-aminated aroyl/acetylnaphthalenes through [4+2] annulations

We have developed a base promoted simple, efficient and alternative approach for the synthesis of 4-amino-3-aroyl//heteroaroyl/acetyl-2-methylsulfanyl-naphthalene-1-carbonitriles by reaction of easily accessible 3,3-bis(methylthio)-1-aryl/heteroaryl/acetylprop-2-en-1-one and 2-cyanomethyl-benzonitrile. Reaction of 1-(2-halo/methoxy-phenyl)-3,3-bis(methylthio)prop-2-en-1-one and 2-cyanomethyl-benzonitrile under basic conditions also afforded 6-(methylthio)-7-oxo-7,12-dihydrobenzo[c]acridine-5-carbonitrile along with usual product. Structure of the synthesized product has been confirmed by single X-ray crystallography.     

Microwave-assisted sol-gel synthesis of CeO2–NiO nanocomposite based NO2 gas sensor for selective detection at lower operating temperature

The progress in the development of gas sensors has considerably grown using some novel nanomaterials of metal, metal oxide and composite. In the current study, we intended and evaluated the properties of nanomaterials like CeO₂, NiO, and CeO₂–NiO composite and its application as NO₂ gas sensor. Sensing of low concentration of NO₂ gas at optimum functional temperature was succeeded using CeO₂–NiO nanocomposites (NCs) film. The working temperature ranges in between 100 and 225 ?°C. Highly crystalline nanomaterials (CeO₂, NiO and CeO₂–NiO) have been prepared by applying microwave-assisted sol-gel route. The as-prepared nanomaterials are characterized for their structure, size, morphology and constitution by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis. XRD studies of nanoparticles reveal the formation of nanoscale CeO₂ and NiO with crystallite size 26, 23 ?nm, respectively. Both are having a face centered cubic structure. The nanocomposite (NC) Ce:Ni ?= ?60:40 has crystallite size of 13 ?nm. XRD study of NCs shows assimilation of Ni metal into the ceria and proves physical similarities of two phases. It can be observed from SEM that prepared NC has a porous surface which enables more surface active sites for adsorbing oxygen. The optical properties are measured with the help of UV–Vis. Spectroscopy. Optical band gaps of 3.19, 3.41 and 2.9 ?eV were observed for CeO_2, NiO nanoparticles (NPs) and CeO₂–NiO NC, respectively. Gas sensing properties state that the NC material shows a higher gas response % of 67.34% for NO₂ gas (25 ?ppm) at comparatively low operating temperature (125 ?°C). It gives response time as (～28 ?s) and the recovery (～54 ?s). NiO incorporation in CeO₂ results in a decline of operating temperature of NC and improves the sensing features.     

Lanthanum sulfide-manganese sulfide/graphene oxide (La2S3-MnS/GO) composite thin film as an electrocatalyst for oxygen evolution reactions

Journal of Solid State Electrochemistry - In this study, the lanthanum sulfide-manganese sulfide (La2S3-MnS) nanosheet composite films with different thicknesses were grown on graphene oxide (GO)...     

Tuning the antioxidant property of potential calixdrug calix[4]tyrosol: role of aza and thia linkages

Structural Chemistry - Calix[4]arenes are the most renowned and widely studied calix[n]arenes, which are established to have quite a few biological (e.g., antibacterial, antifungal, antioxidant,...     

Unprecedented coloration of rutile titanium dioxide nanocrystalline thin films

In this communication, TiO2 nanocrystalline thin films synthesized by a room temperature (27 degrees C) chemical dip process. To our knowledge, this is first report of the preparation of nanoscale rutile TiO2 particles from common inorganic salt at such low temperature. Interestingly, unprecedented dynamic color change accompanies with titanium dioxide grain size, which can be seen with the naked eye that generated curiosity in our mind to check UV-vis absorption, where significant changes were observed. The room temperature synthesized thin films of rutile titanium dioxide make it a potential candidate for high-compatibility material, which can be used in artificial heart valves.     

Towards a microchannel‐based X‐ray detector with two‐dimensional spatial and time resolution and high dynamic range

X‐ray detectors that combine two‐dimensional spatial resolution with a high time resolution are needed in numerous applications of synchrotron radiation. Most detectors with this combination of capabilities are based on semiconductor technology and are therefore limited in size. Furthermore, the time resolution is often realised through rapid time‐gating of the acquisition, followed by a slower readout. Here, a detector technology is realised based on relatively inexpensive microchannel plates that uses GHz waveform sampling for a millimeter‐scale spatial resolution and better than 100 ps time resolution. The technology is capable of continuous streaming of time‐ and location‐tagged events at rates greater than 10⁷ events per cm². Time‐gating can be used for improved dynamic range.     

Single‐Crystal‐like Nanoporous Spinel Oxides: A Strategy for Synthesis of Nanoporous Metal Oxides Utilizing Metal‐Cyanide Hybrid Coordination Polymers

Development of a new method to synthesize nanoporous metal oxides with highly crystallized frameworks is of great interest because of their wide use in practical applications. Here we demonstrate a thermal decomposition of metal‐cyanide hybrid coordination polymers (CPs) to prepare nanoporous metal oxides. During the thermal treatment, the organic units (carbon and nitrogen) are completely removed, and only metal contents are retained to prepare nanoporous metal oxides. The original nanocube shapes are well‐retained even after the thermal treatment. When both Fe and Co atoms are contained in the precursors, nanoporous Fe?Co oxide with a highly oriented crystalline framework is obtained. On the other hand, when nanoporous Co oxide and Fe oxide are obtained from Co‐ and Fe‐contacting precursors, their frameworks are amorphous and/or poorly crystallized. Single‐crystal‐like nanoporous Fe?Co oxide shows a stable magnetic property at room temperature compared to poly‐crystalline metal oxides. We further extend this concept to prepare nanoporous metal oxides with hollow interiors. Core‐shell heterostructures consisting of different metal‐cyanide hybrid CPs are prepared first. Then the cores are dissolved by chemical etching using a hydrochloric acid solution (i.e., the cores are used as sacrificial templates), leading to the formation of hollow interiors in the nanocubes. These hollow nanocubes are also successfully converted to nanoporous metal oxides with hollow interiors by thermal treatment. The present approach is entirely different from the surfactant‐templating approaches that traditionally have been utilized for the preparation of mesoporous metal oxides. We believe the present work proves a new way to synthesize nanoporous metal oxides with controlled crystalline frameworks and architectures.     

A Fluorescent and Colorimetric Sensor for Nanomolar Detection of Co2+ in Water

A new disulfide‐based, imine‐linked fluorescent receptor 1 was processed into organic nanoparticles (ONPs) with an average particle size of 79 nm. The photophysical properties of the ONPs were evaluated by UV/Vis absorption spectroscopy. Receptor 1 selectively recognized Co²⁺ ions in water with a detection limit down to 88 nm.     

Plant Extract: A Promising Biomatrix for Ecofriendly,Controlled Synthesis of Silver Nanoparticles

Uses of plants extracts are found to be more advantageous over chemical, physical and microbial (bacterial, fungal, algal) methods for silver nanoparticles (AgNPs) synthesis. In phytonanosynthesis, biochemical diversity of plant extract, non-pathogenicity, low cost and flexibility in reaction parameters are accounted for high rate of AgNPs production with different shape, size and applications. At the same time, care has to be taken to select suitable phytofactory for AgNPs synthesis based on certain parameters such as easy availability, large-scale nanosynthesis potential and non-toxic nature of plant extract. This review focuses on synthesis of AgNPs with particular emphasis on biological synthesis using plant extracts. Some points have been given on selection of plant extract for AgNPs synthesis and case studies on AgNPs synthesis using different plant extracts. Reaction parameters contributing to higher yield of nanoparticles are presented here. Synthesis mechanisms and overview of present and future applications of plant-extract-synthesized AgNPs are also discussed here. Limitations associated with use of AgNPs are summarised in the present review.