Restricted Intramolecular Rotation: A Dual Fluorescence Response to Hg Quenching and Ag Enhancement in Live Rhizoctonia Solani Cells.

A novel imidazo[1,2-a]pyridine derivative probe (R) was designed, synthesized, and characterized via various characterization techniques, such as ESI-MS, H NMR, C NMR, and Dept-135 NMR. The data obtained from single-crystal XRD reveal that probe R has a coplanar configuration and is part of the monoclinic crystal system, designated the P2(1)/n space group. The fluorescence of (R) is further enhanced by silver (I) ions.

Wavelength specific aggregation induced emission in aqueous media permits selective detection of Ag and Hg ions.

A new 1,8-naphthalimide derivative (probe 1) adopts V-shaped structure, emits fluorescence and displays the Mie effect and aggregation-induced emission (AIE). Selective interactions of thiophilic Ag and Hg ions (10 µM) with 1 (10 µM) resulted in AIEs at 499 and 521 nm, respectively. Both Ag and Hg induce the formation of 1:2 complexes with 1, leading to the formation of AIE active aggregates with an average size of 423 and 198 nm, respectively.

A fluorescent chemosensor for selective detection of chromium (III) ions in environmentally and biologically relevant samples.

A simple single step one pot multicomponent reaction was performed to synthesize N-(tert-butyl)-2-(furan-2-yl)imidazo[1,2-a]pyridine-3-amine (TBFIPA). The synthesized TBFIPA was subjected to library of cations to study its ability for selective and sensitive detection of specific metal ions. Selective detection of chromium ions by TBFIPA were found from the significant hypsochromic shift (335 nm → 285 nm) in the UV-Visible spectra.

Coordination of Distal Carboxylate Anion Alters Metal Ion Specific Binding in Imidazo[1,2-a]pyridine Congeners.

Imidazo[1,2-a]pyridine derivatives have excellent potential for chelation with transition metal ions. Two new imidazo[1,2-a]pyridine-8-carboxylates were synthesized and characterized by H NMR, C NMR, HRMS, and single crystal-XRD techniques. Methyl carboxylate (probe 1) turns on fluorescence upon coordination with Zn, while sodium carboxylate (probe 2) turns off its fluorescence upon coordination with Co or Cu ions present in aqueous acetonitrile medium.

Significant perspectives on various viral infections targeted antiviral drugs and vaccines including COVID-19 pandemicity.

A virus enters a living organism and recruits host metabolism to reproduce its own genome and proteins. The viral infections are intricate and cannot be completely removed through existing antiviral drugs. For example, the herpes, influenza, hepatitis and human immunodeficiency viruses are a few dreadful ones amongst them.

A comprehensive overview of vaccines developed for pandemic viral pathogens over the past two decades including those in clinical trials for the current novel SARS-CoV-2.

The unprecedented coronavirus disease 2019 (COVID-19) is triggered by a novel strain of coronavirus namely, Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2). Researchers are working around the clock to control this pandemic and consequent waves of viral reproduction, through repurposing existing drugs as well as designing new vaccines. Several countries have hastened vaccine design and clinical trials to quickly address this outbreak.

Synthesis and electrochemical properties of environmental free l-glutathione grafted graphene oxide/ZnO nanocomposite for highly selective piroxicam sensing.

A simple and reliable strategy was proposed to engineer the glutathione grafted graphene oxide/ZnO nanocomposite (glutathione-GO/ZnO) as electrode material for the high-performance piroxicam sensor. The prepared glutathione-GO/ZnO nanocomposite was well characterized by X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). The novel nanocomposite modified electrode showed the highest electrocatalytic activity towards piroxicam (oxidation potential is 0.

A novel isatin-based probe for ratiometric and selective detection of Hg and Cu ions present in aqueous and environmental samples.

A novel isatin derivative (1) is UV-Visible active and displays about 90 nm bathochromic shift upon interaction with only Hg and Cu, but not with other common metal ions. Also, the colorless probe 1 turns to brick-red and yellow in the presence of Hg and Cu, respectively. Addition of increasing amounts of Hg or Cu to 1 leads to the emergence of a new absorption at ~470 nm (due to LMCT), with a concomitant decrease in the intensity of absorption of 1 at ~380 nm, and thereby provides a ratiometric response.

Design and synthesis of a novel peptide for selective detection of cancer cells.

Using a minimalist approach, an 11-residue peptide (Peptide 1) tagged with rhodamine fluorophore was designed and synthesized for selective detection of cancer cells. Peptide 1 contains RGD and NGR motifs to bind, respectively, integrins and aminopeptidase CD13, which are over expressed in cancer cells. Surface tension measurements revealed that peptide 1 possess surface-active property owing to the overall hydrophobicity and cationic nature of the peptide.

Synchronous detection of cadmium and lead in honey, cocos nucifera and egg white samples using multiwalled carbon nanotube/hyaluronic acid/amino acids nanocomposites.

Electrochemical Synchronous detection of cadmium (Cd(II)) and lead (Pb(II)) was obtained by acid treated multiwalled carbon nanotube (A-MWCNT) functionalized with hyaluronic acid (Hyalu) and this mixture was separately further modified with l-cysteine (l-Cys) and l-serine (l-Ser). Under the optimized circumstance best voltammetric responses were produced by A-MWCNT/Hyalu/l-Cys and A-MWCNT/Hyalu/l-Ser modified electrodes. The peak current was linearly dependent on the Cd(II) and Pb(II) concentrations in the range from 0.

Chelation of specific metal ions imparts coplanarity and fluorescence in two imidazo[1,2-a]pyridine derivatives: Potential chemosensors for detection of metal ions in aqueous and biosamples.

Synthesis and chelation induced fluorescence emission from two imidazo[1,2-a]pyridine derivatives are described. The nonfluorescent molecule 1 containing N and O donor atoms, achieves coplanarity upon interactions with trivalent cations Al, Fe and Cr, that favors fluorescence emission. Molecule 2 containing two N donor atoms attains coplanarity upon interaction with the only Zn and becomes fluorescent.

Crystal structure and Hirshfeld surface analysis of two imidazo[1,2-]pyridine derivatives: --butyl-2-(4-meth-oxy-phen-yl)-5-methyl-imidazo[1,2-]pyridin-3-amine and --butyl-2-[4-(di-methyl-amino)-phen-yl]imidazo[1,2-]pyridin-3-amine.

In the title imidazo[1,2-]pyridine derivatives, --butyl-2-(4-meth-oxy-phen-yl)-5-methyl-imidazo[1,2-]pyridin-3-amine, CHNO, (I), and --butyl-2-[4-(di-methyl-amino)-phen-yl]imidazo[1,2-]pyridin-3-amine, CHN, (II), the 4-meth-oxy-phenyl ring in (I) and the 4-(di-methyl-amino)-phenyl ring in (II) are inclined to the respective imidazole rings by 26.69 (9) and 31.35 (10)°.

Development of antiviral inhibitor against dengue 2 targeting Ns3 protein: In vitro and in silico significant studies.

Dengue fever is a severe, widespread disease with more than 2 million diagnosed infections per year. The Dengue virus protease represents a cardinal target for prudent drug design. Among the four serotypes Dengue 2 is known for the occurrence of its frequent epidemics.

Ultra sensitive detection of Cd (II) using reduced graphene oxide/carboxymethyl cellulose/glutathione modified electrode.

The present work describes the electrochemical detection of Cd using reduced graphene oxide (rGO), carboxymethyl cellulose (CMC) and glutathione (GSH) modified glassy carbon electrode (GCE) by Square Wave Anodic Stripping Voltammetry (SWASV). The prepared nanocomposite was characterized by X-ray diffraction (XRD), RAMAN, Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) and X-ray photoelectron spectroscopy (XPS), Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). The influence of experimental parameters such as effect of pH, choice of supporting electrolyte, deposition time and deposition potential, were optimized.

A novel voltammetric sensor for the simultaneous detection of Cd and Pb using graphene oxide/κ-carrageenan/l-cysteine nanocomposite.

Simultaneous determination of Cd and Pb was achieved by using graphene oxide/κ-carrageenan/l-cysteine (GO/κ-Car/l-Cys) nanocomposite modified glassy carbon electrode (GCE) by Square Wave Anodic Stripping Voltammetry (SWASV). The morphology and functionalization of the prepared nanocomposite were characterized by XRD analysis, Raman spectroscopy, Field emission scanning electron microscopy and FTIR analysis. Under optimum conditions, outstanding linearity was obtained for both Cd and Pb in the range from 5 to 50nM with the detection limits as 0.

Diastereoselective tandem oxidation/Michael/aldol reaction: unprecedented formation of dispirocyclopentanebisoxindoles and dispiro[acenaphthylene-1,1'-cyclopentane-3',1''-acenaphthylene]-2,2''diones.

An unprecedented tandem oxidation/Michael/aldol reaction is reported. The diastereoselective formation of only a single isomer of dispirocyclopentanebisoxindole and dispiro[acenaphthylene-1,1'-cyclopentane-3',1''-acenaphthylene]-2,2''dione is presented. The reaction generates two new C-C bonds and two all-carbon quaternary chiral stereocenters in a single step.

Antiviral activity of Thiosemicarbazones derived from α-amino acids against Dengue virus.

The endemicity and seasonal outbreaks of Dengue disease in most tropical and subtropical countries underscores an urgent need to develop effective prevention and control measures. Development of a Dengue vaccine, which is complicated by the Antibody Dependent Enhancement effect (ADE), a viral inhibitor, seems prudent as it would inhibit the spread of the virus. In vitro methods such as MTT assay and plaque formation unit reduction assays were employed for screening the viral inhibitory property of α-amino acid based Thiosemicarbazides.

Selective interactions of trivalent cations Fe³⁺, Al³⁺ and Cr³⁺ turn on fluorescence in a naphthalimide based single molecular probe.

Synthesis and fluorescence turn-on behavior of a naphthalimide based probe is described. Selective interactions of trivalent cations Fe(3+), Al(3+) or Cr(3+) with probe 1 inhibit the PET operating in the probe, and thereby, permit the detection of these trivalent cations present in aqueous samples and live cells. Failure of other trivalent cations (Eu(3+), Gd(3+) and Nb(3+)) to inhibit the PET process in 1 demonstrates the role of chelating ring size vis-à-vis ionic radius in the selective recognition of specific metal ions.

Lewis acid catalyzed unprecedented [3 + 2] cycloaddition yields 3,3'-pyrrolidinyldispirooxindoles containing four contiguous chiral stereocenters with two contiguous quaternary spirostereocenters.

A Lewis acid catalyzed domino reaction cascades through azide-alkene cycloaddition, rearrangement, aziridine ring opening, and azomethine cycloaddition with a parent dipolarophile, resulting in 3,3'-pyrrolidinyldispirooxindoles containing four contiguous chiral stereocenters with two contiguous quaternary spirostereocenters.

Resveratrol stabilized gold nanoparticles enable surface loading of doxorubicin and anticancer activity.

The green synthesis of gold nanoparticles was achieved by exploiting the antioxidant property of resveratrol (R). The formation of resveratrol stabilized gold nanoparticles (R-GNPs) was confirmed by the observation of the surface plasmon resonance band at 537 nm. The average size of R-GNPs produced in resveratrol medium was ~35nm.

Ethyl 8''-chloro-1'-methyl-2,12''-dioxo-12''H-di-spiro-[indoline-3,2'-pyrrolidine- 3',6''-indolo[2,1-b]quinazoline]-4'-carboxyl-ate.

In the title compound, C29H23ClN4O4, the quinazoline-indole system and the indolin-2-one system are each essentially planar, with maximum deviations from their mean planes of 0.150 (2) and 0.072 (2) Å, respectively.

Tuning copper(II) ion selectivity: the role of basicity, size of the chelating ring and orientation of coordinating atoms.

Incorporation of the triazolyl moiety modulates the basicity and effective size of the chelating ring, changes the stoichiometry in complex formation and thereby imparts Cu(2+) ion selectivity.

Draft Genome Sequence of a Highly Flagellated, Fast-Swimming Archaeon, Methanocaldococcus villosus Strain KIN24-T80 (DSM 22612).

We report the draft genome sequence of a hyperthermophilic Methanocaldococcus villosus strain, KIN24-T80. The gene associated with its heavy flagellum formation was annotated in the 1.2-Mb draft genome sequence, and this strain may be a good model system to study the extensive functional role of flagella and their fast motor activity.

N-tert-Butyl-2-(2,6-di-chloro-phen-yl)imidazo[1,2-a]pyrazin-3-amine.

In the title compound, C16H16Cl2N4, the imidazole ring mean plane makes a dihedral angle of 70.01 (1)° with the phenyl ring. The Cl atoms deviate by -0.

Ethyl 1''-benzyl-2''-oxo-2',3',5',6',7',7a'-hexa-hydro-1'H-di-spiro-[indeno-[1,2-b]quinoxaline-11,2'-pyrrolizine-3',3''-indoline]-1'-carboxyl-ate monohydrate.

In the title compound, C38H32N4O3·H2O, the quinoxaline-indene and pyrrolizine systems are essentially planar, with maximum deviations from their mean planes of 0.162 and 0.563 Å, respectively.