Glutathione-Mediated Synthesis of WO3 Nanostructures with Controllable Morphology/Phase for Energy Storage, Photoconductivity, and Photocatalytic Applications.

Developing an improved synthesis method that controls the morphology and crystal phase remains a substantial challenge. Herein, we report phase and morphology-controlled hydrothermal synthesis of tungsten oxides by varying acid concentration and utilizing glutathione (GSH) as a structural directing agent, together with the exploration of their applications in supercapacitors, photoconductivity, and photocatalysis. Orthorhombic hydrated tungsten oxide (WO3·0.33H2O) with nonuniform block and plate-like morphology was obtained at 3 M hydrochloric acid (HCl). In contrast, nonhydrated monoclinic tungsten oxide (WO3) with smaller rectangular blocks was obtained at 6 M HCl. Further, the addition of GSH results in an increase in the surface area of the materials along with a narrowing of the band gap. Moreover, it plays a pivotal role in regulating the morphology through oriented attachments, Ostwald ripening, and the self-assembly of WO3 nuclei. GHTO and GTO polymorphs showed pseudocapacitive behavior with the highest specific capacitances of 450 and 300 F g-1 at 0.5 A g-1, maintaining 94 and 92% retention stability, respectively, over 1000 cycles at 2 A g-1. Also, the synthesized materials displayed favorable photoconductivity under light irradiation, implying potential utilization in photovoltaic applications. Moreover, these materials exhibited remarkable photocatalytic performance in the degradation of methylene blue (MB) dye, establishing themselves as highly effective photocatalysts. Therefore, nanostructured tungsten oxide showcases its versatility, rendering it an appealing candidate for energy storage, photovoltaic systems, and photocatalysis.

Deciphering the mechanistic insights of 4-nitrophenol reduction catalyzed by a 1D-2D Bi2S3 nanostructured catalyst.

Exploring the reaction mechanism and the role of a catalyst in the conversion of pollutants to value-added products is vital for sustainable development. Herein, a polyvinylpyrrolidone-assisted liquid-phase reflux strategy was utilized to synthesize anisotropic 1D-2D Bi2S3 nanostructures. The as-synthesized nanostructures were used as catalysts in batch experiments for 4-nitrophenol (4-NP) reduction and they exhibited an apparent rate constant (kapp), turnover frequency (TOF), and activation energy (Ea) of 0.441 min-1, 1.543 h-1 and 26.13 kJ mol-1, respectively. Also, the effects of catalyst dosage, NaBH4 amount, 4-NP concentration, solvents, pH, and common ions were evaluated. Isotope labeling and kinetic isotope effects (KIEs) confirm that water is the proton source in 4-NP reduction. Electrochemical studies revealed that the nanostructured 1D-2D Bi2S3 enables the dissociation of BH4- into active absorbed and adsorbed hydrogen () species and assists in the catalytic reduction of 4-NP. This study offers a new insight into designing an efficient nanostructured 1D-2D Bi2S3 catalyst for 4-nitrophenol reduction.

Visible light-driven photocatalytic thiol-ene/yne reactions using anisotropic 1D Bi2S3 nanorods: a green synthetic approach.

Thiol-ene/yne click reactions play a significant role in creating carbon-sulfur (C-S) bonds, and there has been a growing interest in using visible-light photoredox catalysis for their formation. In this study, anisotropic 1D Bi2S3 nanorods were prepared using a simple polyol-assisted reflux method, and they were used as catalysts for the thiol-ene/yne click reactions under visible light irradiation. The developed protocol is highly compatible and tolerant to various substrates with excellent product yields. Also, thiol-ene and -yne reactions achieved maximum TONs of 93 and 95, respectively. Detailed mechanistic studies were conducted and supported by NMR studies, radical trapping utilizing TEMPO, and ESI-MS product analysis. The ability of Bi2S3 nanorods to catalyze thiol-ene/yne reactions is primarily due to the creation of photoexcited holes, which aid in the formation of thiyl radicals. This method can be scaled up to the gram-scale synthesis of benzyl styryl sulfide with an excellent chemical yield of 90%. The 1D Bi2S3 nanorods also demonstrated structural and morphological stability throughout five reaction cycles while maintaining a favorable photocatalytic activity. The developed methodology had the advantages of broad substrate scope, mild reaction conditions, scaled-up synthesis, and nonrequirement of free radical initiators.

Sources, occurrence, and treatment techniques of per- and polyfluoroalkyl substances in aqueous matrices: A comprehensive review.

Per- and polyfluoroalkyl substances (PFAS), a class of synthetic organic pollutants, have prompted concerns about their global prevalence and possible health effects. This review consolidates the most recent data on different aspects of PFAS, such as their occurrence, and prominent sources. The current literature analysis of PFAS occurrence suggests significant variation in their concentration ranging from 0.025 to 1.2 × 108 ng/L in wastewater, 0.01 to 8.9 × 105 ng/L in surface water, and <0.01 to 1.3 × 104 ng/L in groundwater globally. Since conventional treatment techniques are inadequate in remediating PFAS, innovative treatment approaches based on their removal or mineralization mechanism have been comprehensively reviewed. Advanced treatment technologies have shown degradation or removal of PFAS to be around 6 and > 99.9% in different aqueous matrices. However, due to significant drawbacks in their applicability in wastewater treatment plants (WWTPs), a novel treatment train approach has emerged as an effective alternative. This approach synergistically integrates multiple remediation techniques while addressing the impediments of individual treatments. Furthermore, nanofiltration (NF270) combined with electrochemical degradation has been demonstrated to be the most efficient (>98%) treatment train approach in PFAS remediation. If implemented in WWTPs, nanofiltration followed by adsorption using activated carbon is also a viable method for PFAS removal.

Controlled surface functionalization of Ni-S nanostructures for pH-responsive selective and superior pollutants adsorption.

Herein, we developed a synthetic strategy to functionalize Ni-S nanostructures (NS) using a facile precipitation method at moderate temperature. The surface functionality of NS is controlled by varying amount of mixed surfactants to achieve the pH-responsive selective adsorption of anionic and cationic dyes and the adsorption of ciprofloxacin (CIP) and tetracycline (TC) antibiotics. Powder XRD diffraction pattern revealed the phase of NS was changed from α-NiS to mixed phases after functionalization. The surface area of functionalized NS was significantly enhanced by ~5 times of that unfunctionalized NS as 6.6 m2g-1 to 30.3 m2g-1. The NS selectively adsorbed methyl orange (MO) at pH 4.5 and methylene blue (MB) at pH 11.5 with separation efficiency values of 94.2% and 97.9% respectively. The maximum adsorption capacity for MO, MB, TC and CIP are obtained as 1526.3, 1031.2, 1540.8 and 632.4 mg g-1, respectively. The electrostatic interaction is predominantly involved in the adsorption of dyes whereas adsorption of antibiotics changed to hydrogen bonding and metal coordination. Thermodynamics parameters indicated exothermic and spontaneous adsorption of dyes. The optimized adsorbent is easily recyclable. Thus, the developed strategy of functionalization of nanostructures unveils a practical approach towards selective and efficient adsorption of organic pollutants.

Selective removal of anionic dyes with exceptionally high adsorption capacity and removal of dichromate (Cr2O72-) anion using Ni-Co-S/CTAB nanocomposites and its adsorption mechanism.

An adsorbent Ni-Co-S/CTAB nanocomposites have been synthesized at low temperature in aqueous medium using nickel acetate, cobalt acetate, thioacetamide and hexadecyltrimethyl ammonium bromide (CTAB) as reagents. The nanocomposites exhibited exceptionally high adsorption capacity towards anionic adsorbates with high selectivity. The maximum adsorption capacity of nanocomposites were 1995.02 mg g-1 for Congo red (CR), 2223.15 mg g-1 for Methyl orange (MO) anionic dyes and 790.69 mg g-1 for Cr2O72- metal anion. They exhibit negligible adsorption ability towards cationic dyes 2.33 mg g-1 for MB and 42.05 mg g-1 for RhB. The nanocomposite is able to adsorb anionic dyes from a binary mixture of cationic and anionic dyes with high separation factor. It also shows good results with synthetic effluents. The removal of adsorbates followed modified Zhu and Gu isotherm model. FTIR and Zeta-potential measurement confirmed that electrostatic interactions are predominating factor for the adsorption of anionic adsorbates followed by hydrophobic interactions between adsorbates. Moreover, ethanol is used to regenerate the adsorbent and reused up to five times with good adsorption capacities. Thus, the nanocomposite can be used as an efficient adsorbent for the removal and seperation of anionic adsorbates from binary mixtures as well as synthetic effluents.

A Small Insulinomimetic Molecule Also Improves Insulin Sensitivity in Diabetic Mice.

Dramatic increase of diabetes over the globe is in tandem with the increase in insulin requirement. This is because destruction and dysfunction of pancreatic ß-cells are of common occurrence in both Type1 diabetes and Type2 diabetes, and insulin injection becomes a compulsion. Because of several problems associated with insulin injection, orally active insulin mimetic compounds would be ideal substitute. Here we report a small molecule, a peroxyvanadate compound i.e. DmpzH[VO(O2)2(dmpz)], henceforth referred as dmp, which specifically binds to insulin receptor with considerable affinity (KD-1.17µM) thus activating insulin receptor tyrosine kinase and its downstream signaling molecules resulting increased uptake of [14C] 2 Deoxy-glucose. Oral administration of dmp to streptozotocin treated BALB/c mice lowers blood glucose level and markedly stimulates glucose and fatty acid uptake by skeletal muscle and adipose tissue respectively. In db/db mice, it greatly improves insulin sensitivity through excess expression of PPARγ and its target genes i.e. adiponectin, CD36 and aP2. Study on the underlying mechanism demonstrated that excess expression of Wnt3a decreased PPARγ whereas dmp suppression of Wnt3a gene increased PPARγ expression which subsequently augmented adiponectin. Increased production of adiponectin in db/db mice due to dmp effected lowering of circulatory TG and FFA levels, activates AMPK in skeletal muscle and this stimulates mitochondrial biogenesis and bioenergetics. Decrease of lipid load along with increased mitochondrial activity greatly improves energy homeostasis which has been found to be correlated with the increased insulin sensitivity. The results obtained with dmp, therefore, strongly indicate that dmp could be a potential candidate for insulin replacement therapy.

A quantum dot-MUC1 aptamer conjugate for targeted delivery of protoporphyrin IX and specific photokilling of cancer cells through ROS generation.

Non-targeted photosensitizers lack selectivity that undermines the potential use of photodynamic therapy (PDT). Herein, we report the DNA mediated assembly of a ZnSe/ZnS quantum dot (QD)-photosensitizer (PS)-Mucin 1(MUC1) aptamer conjugate for targeting the MUC1 cancer biomarker and simultaneous generation of reactive oxygen species (ROS). A photosensitizer, protoporphyrin IX (PpIX), was conjugated to a single stranded DNA and self-assembled to a complementary strand that was conjugated to a QD and harboring a MUC1 aptamer sequence. A multistep fluorescence resonance energy transfer (FRET) is shown that involves the QD, PpIX and covalently linked CF™ 633 amine dye (CF dye) to the MUC1 peptide that tracks the potency of the aptamer to attach itself with the MUC1 peptide. Since the absorption spectra of the CF dye overlap with the emission spectra of PpIX, the former acts as an acceptor to PpIX forming a second FRET pair when the dye labeled MUC1 binds to the aptamer. The binding of the QD-PpIX nanoassemblies with MUC1 through the aptamer was further confirmed by gel electrophoresis and circular dichroism studies. The selective photodamage of MUC1 expressing HeLa cervical cancer cells through ROS generation in the presence of the QD-PpIX FRET probe upon irradiation is successfully demonstrated.

Synthesis of Tunable Band Gap Semiconductor Nickel Sulphide Nanoparticles: Rapid and Round the Clock Degradation of Organic Dyes.

Controlled shape and size with tuneable band gap (1.92-2.41 eV), nickel sulphide NPs was achieved in presence of thiourea or thioacetamide as sulphur sources with the variations of temperature and capping agents. Synthesized NPs were fully characterized by powder XRD, IR, UV-vis, DRS, FE-SEM, TEM, EDX, XPS, TGA and BET. Capping agent, temperature and sulphur sources have significant role in controlling the band gaps, morphology and surface area of NPs. The catalytic activities of NPs were tested for round the clock (light and dark) decomposition of crystal violet (CV), rhodamine B (RhB), methylene blue (MB), nile blue (NB) and eriochrome black T (EBT). Agitation speed, temperature, pH and ionic strength have significant role on its catalytic activities. The catalyst was found to generate reactive oxygen species (ROS) both in presence and absence of light which is responsible for the decomposition of dyes into small fractions, identified with ESI-mass spectra.

Melamine-DNA encoded periodicity of quantum dot arrays.

Formation of QD-array in solution phase guided by the self-assembly with DNA-melamine hybrid molecules is reported here. Melamine was conjugated with ssDNA using phosphoramidate chemistry. Aqueous soluble ZnSe/ZnS QDs conjugated to complementary ssDNA was self-assembled with the DNA-melamine hybrid molecules by DNA-hybridization. The self-assembly leads to the precise positioning of the QDs in QDs array where the inter QD distance is being maintained by the DNA sequence length. The QD array was characterized by gel electrophoresis, UV-visible and fluorescence spectrophotometry and circular dichroism. Direct visualization of the DNA-melamine hybrid molecule mediated QD array was made possible by atomic force microscopy (AFM) and transmission electron microscopy (TEM) analysis. Substantial increase in the fluorescence intensity and lifetime of the QDs was observed on array formation by DNA self-assembly.

DNA mediated assembly of quantum dot-protoporphyrin IX FRET probes and the effect of FRET efficiency on ROS generation.

Photodynamic therapy (PDT) involves generation of reactive oxygen species (ROS) by the irradiation of a photosensitizer. Controlled and targeted release of ROS by a photosensitizer is crucial in PDT. For achieving controlled generation of ROS, a ZnSe/ZnS quantum dot (QD) donor and protoporphyrin IX (Pp IX) acceptor based fluorescence resonance energy transfer (FRET) probe is reported here. The QDs and Pp IX are assembled either by direct conjugation or through DNA hybridization. Complementary DNA strands are individually conjugated to the QDs and Pp IX by amide coupling. Due to the overlap of the emission spectrum of QDs and the absorption spectrum of Pp IX, efficient transfer of energy from QDs to Pp IX was observed in both the cases. The FRET efficiency was quantitatively evaluated by steady-state and time-resolved spectroscopy and compared between the QD-Pp IX direct conjugate and QD-DNA-Pp IX assembly at various donor to acceptor ratios. Since a single QD can harbor a multiple number of Pp IX-DNA counterparts through DNA hybridization, the FRET efficiency was found to increase with the increase in the number of Pp IX acceptors. ROS generation from Pp IX was studied for the FRET pairs and was found to be affected by the irradiation time of the QD donor.

Di-chlorido-(N,N-diethyl-4-{[(quinolin-2-yl)methyl-idene]amino-κ(2) N,N'}aniline)mercury(II).

In the mononuclear title complex, [HgCl2(C20H21N3)], synthesized from the quinoline-derived Schiff base N (1),N (1)-diethyl-N (4)-(quinolin-2-yl-methyl-idene)benzene-1,4-di-amine (QMBD), the coordination geometry around the Hg(2+) atom is distorted tetra-hedral, comprising two Cl atoms [Hg-Cl = 2.3654 (19) and 2.4394 (18) Å] and two N-atom donors from the QMBD ligand, viz. one imine and quinoline [Hg-N = 2.334 (5) and 2.340 (5) Å, respectively]. In the crystal, weak C-H⋯Cl hydrogen bonds and weak π-π aromatic ring stacking inter-actions [minimum ring-centroid separation = 3.680 (4) Å] give an overall three-dimensional network.

One-pot fabrication of high-quality InP/ZnS (core/shell) quantum dots and their application to cellular imaging.

True colors: High-quality InP and InP/ZnS quantum dots (QDs) are obtained by means of a simple one-pot method in the presence of polyethylene glycol (PEG). Rapid and size-controlled reactions lead to highly crystalline and nearly monodisperse QDs at relatively low temperatures. The particles emit from cyan blue to far-red, and are successfully used in cellular imaging (see figure).