Sahid Hussain

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).

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.

Under dark and visible light: fast degradation of methylene blue in the presence of Ag–In–Ni–S nanocomposites

Ag–In–Ni–S nanocomposites of different shapes were productively achieved in water using thioacetamide at different temperatures in the presence of SDS with uniform size distributions. It was found that variation of the sodium dodecyl sulphate (SDS) concentration and the temperature had a significant influence on the morphology of Ag–In–Ni–S and the photocatalytic activity. The newly synthesized Ag–In–Ni–S nanocomposites were fully characterized by powder XRD, IR, UV-vis, DRS, FE-SEM, TEM, EDX, XPS, BET and TGA. The catalytic activities were measured by the degradation of methylene blue (MB) in the absence and presence of visible light (sunlight and 100 W tungsten lamp). The catalyst was found to be effective in degrading MB through the generation of reactive oxygen species (ROS) which was confirmed using terephthalic acid (TA), dihydrorhodamine 123 (DHR123) treatment and ESI mass spectroscopy. The removal efficiency of MB by the nanocomposites is very fast, nearly quantitative and repeatable up to five cycles.

An efficient synthesis of quinolines under solvent-free conditions

An efficient synthesis of substituted quinolines has been achieved in a one-pot reaction from o-nitrobenzaldehyde and enolizable ketones using SnCl2·2H2O as the reductant under microwave irradiation without any solvent or catalyst

Multicomponent domino reactions: borax catalyzed synthesis of highly functionalised pyran-annulated heterocycles

A collection of pyrano[3,2-c] chromene, 4H-chromene and 4H-pyran were synthesized in excellent yield employing an innocuous, inexpensive and naturally occurring borax-catalyzed multicomponent domino reaction. The present protocol offers advantages in terms of higher yields, short reactions time and no workup and no column chromatography.

Borax catalyzed domino reactions: synthesis of highly functionalised pyridines, dienes, anilines and dihydropyrano[3,2-c]chromenes

Borax, an innocuous, inexpensive, and a naturally occurring material, very efficiently catalyzes the Knoevenagel condensation and Michael addition in domino fashion for the construction of highly functionalised pyridines, dienes, anilines and dihydropyrano[3,2-c]chromenes. The present protocol offers advantages in terms of higher yields, wide scope of substrates, operational simplicity, short reaction time, no requirement of workup or column chromatography, and easy access to a wide range of structurally diverse functionalized molecules of biological importance. Recycling of the catalyst and scaling up of the reactions are important attributes of this catalytic process.

Di­chlorido­(N,N-diethyl-4-{[(quinolin-2-yl)methyl­idene]amino-κ2N,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-ylmethylidene)benzene-1,4-diamine (QMBD), the coordination geometry around the Hg2+ atom is distorted tetrahedral, 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 interactions [minimum ring-centroid separation = 3.680 (4) Å] give an overall three-dimensional network.

Base free synthesis of iron oxide supported on boron nitride for the construction of highly functionalized pyrans and spirooxindoles

Boron nitride supported iron oxide (BN@Fe3O4) network was achieved via chemical reduction followed by aerial oxidation in absence of base. The prepared BN@Fe3O4 was characterized by powder XRD, FT-IR, Raman, BET and FE-SEM. The catalytic property was subsequently investigated for one-pot multicomponent domino reaction for the synthesis of highly functionalized pyrans and spirooxindoles derivatives on water. The present method is simple, high yielding, recyclable and requires no column chromatography.

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 β-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.

Photoinduced oxygen prompted iron–iron oxide catalyzed clock reaction: a mimic of the blue bottle experiment

Mixed-valent iron–iron oxide nanoparticles were synthesized by the reduction of Fe2+ to Fe0 followed by aerial oxidation, and were fully characterized using powder XRD, FE-SEM, EDX, and XPS. A clock reaction of organic dyes (methylene blue, nile blue and crystal violet) was performed with iron–iron oxide nanoparticles, where periodic colour changes were observed. The decolourization of the dyes was very fast (within 7–12 min), whereas colour regeneration took a relatively longer time (up to 90 min). Furthermore, this clock reaction was found to be dependent on light and atmospheric oxygen. Light speeds up the generation of electron–hole pairs that are responsible for the reduction of the dyes, whereas oxygen is required for the colour regeneration.