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This study aimed to synthesize a silver nanocomposite hydrogel based on poly (acrylic acid) and poly (vinyl pyrrolidone) grafted onto salep biopolymer and its use in controlled drug release. Drug release is one of the medicine goals that have been happening in the different methods, such as injections, pills or sprays. The useful drug dose, has measured by the drug concentration in the blood system, in the specific time. Researches have shown, in above methods, at the first time there is a high concentration of drug in the blood and by passing the time, this concentration decreases, so for achieve the useful drug dose, more drug is needed which it usually causes the increasing of the drug side effects. Thus for preventing these side effects, controlled drug release is investigated in this research. To identify the synthesized hydrogel, Fourier transform infrared spectroscopy (FTIR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermometric gravimetric analysis (TGA) were used. The results showed that the release of deferasirox from the silver nanocomposite hydrogel network is related to the pH of the environment. In addition, the biodegradability and biocompatibility of this system have led to its use in the pharmaceutical industry.

In this work, magnetic nanocomposite hydrogel was produced via grafting copolymerization of acrylic acid (AA) and acrylamide (AAm) in the presence of MnFe2O4@SiO2@Vinyltrimethylsilane (VTMS) as a cross-linking agent. To effectively absorb Pb (II) and Cd (II) from an aqueous solution, the prepared magnetic nanocomposite hydrogel was applied. XRD, VSM, FT-IR, SEM, EDS, and TEM VSM, SEM, TEM, EDS, FT-IR, and XRD spectroscopic methods validated the structure of the prepared nanocomposite hydrogel. In addition, thermal characteristics were evaluated by TGA and DTG. The features that influence the absorption of heavy metal ions include pH solution, treatment time, starting concentration of ions, temperature, and sorbent quantity experimented. Employing Langmuir, Freundlich, and Temkin, the adsorption isotherm was investigated at various temperatures. The adsorption data best fitted The Langmuir isotherm model. The absorption kinetics models such as intraparticle, pseudo-first-order, pseudo-second-order in metal ion solutions of 25, 50, 100, and 150 mg/L-1 were studied. The absorption results were well explained by pseudo-first-order model. The maximal absorption capacities of magnetic nanocomposite hydrogel for Pb (II) and Cd (II) elimination from a 150 mg/L-1 metal solution were 131 and 126 mg/g, respectively. The absorbent was employed effectively for four cycles of adsorption and desorption. Therefore, the nanocomposite hydrogel examined in this work may be used for various water filtration purposes, notably for the elimination of toxic metals.

Under favorable conditions, we have designed a one-pot multicomponent reaction combining aromatic amines, aldehydes, nitroalkanes, and 1-dicarbonyl compounds in conjunction with the presence of the Ni(II)-Schiff base/SBA-15 as a heterogeneous catalyst to generate a range of functionalized pyrroles in reasonable to excellent yields. We present a methodology that results in a high yield percentage, a short reaction time of approximately 8 hours, mild reaction conditions of 70°C, a wide range of substrates, the possibility of large-scale synthesis, low cost, and the avoidance of hazardous reagents/solvents. In addition, this method can synthesize more desirable pyrroles by adding or altering numerous functional groups to the reactants in a one-pot process. Specifically, a Hammett plot variant was employed to evaluate the reaction effectively.

Anticancer drugs play important roles in cancer treatment. However, these drugs have many disadvantages such as poor solubility, high toxicity, and serious side effects like hair loss, nausea and vomiting, anemia etc. To overcome these drawbacks, many attempts have been made to develop novel controlled drug delivery systems. They can encapsulate the drug and release it to the cancer site without leaking into other sites. The employment of multi-responsive hydrogels as a drug delivery system have some advantages over other drug delivery systems due to their ease of preparation, high efficiency, high-water content, tunable physical, and biological properties. The most advantages of these hydrogels is the volume phase transitions in their cross-linked three-dimensional networks as exposure to external stimuli such as temperature, pH, pressure, electric field, magnetic field and light. There has been research on other drug delivery systems which can respond to changes in pH and temperature for targeted drug release. Among those,gels have been studied mostly for their dual responsiveness. This provides an update on progress of gel based dual pH and temperature responsive drug delivery systems. Various systems under these categories for targeted and controlled delivery of different classes of drugs such as ant diabetic and antibiotic drugs with special emphasis on anticancer drugs are discussed in this review.

In this study, we synthesized the benzopyrano[3,2-c]chromene-6,8-dione derivativesby one-pot multi-component reaction of 1,3-cyclohexanedione, arylaldehydes, and 4-hydroxycoumarin under the solventless condition using Cu(II)-Schiff base/SBA-15 as a reusable heterogeneous catalyst in high yields. These kinds of catalysts are built from mesoporous silica SBA-15 which is covalently anchored with Cu(II)-Schiff base complex. The high yields, simple work-up procedure, reuseability of the catalyst, and environmentally friendly conditions are the main advantages of this method compared to the other techniques. The products were identified by using 1H NMR, mass and IR spectra, which were compared to those reported previously.

In this study, at first, gold nanorods (GNRs) were synthesized and then they were coated with a layer of hydrogel composed of poly(N-isopropylacrylamide) (PNIPAM) grafted onto carboxymethyl cellulose (CMC) as a backbone. The chemical structure of GNRs/PNIPAM-g-CMC hydrogel was characterized by Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), atomic-force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The swelling properties of the obtained GNRs/PNIPAM-g-CMC hydrogel were studied at different times and temperatures. In addition, drug release from doxorubicin-loaded GNRs/PNIPAM-g-CMC hydrogel was examined at different temperatures during time. The drug release mechanism was studied by first-order, second-order, and Ritger–Peppas models. Finally, the GNRs/PNIPAM-g-CMC hydrogel biocompatibility was tested against L929 mouse fibroblast cells by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) method. Our study suggests that GNRs coated with low-cost hydrogels can be excellent candidate for drug delivery systems.

A novel optical nano-sensor for tetracycline hydrochloride (TH) detection as a small molecule model was prepared by modifying the surface of CdTe/ZnS QDs with a biopolymer based cap, called poly ((2-dimethylaminoethyl) methacrylate) grafted onto oxidized starch (OS-g- PDMAEMA), via a facile method. The preparation of the nano-sensor was optimized by employing a 4-factor Box–Behnken statistical design to achieve a nano-sensor with maximum fluorescence intensity for sensitive determination of TH in real samples. The optimized nano-sensor based on CdTe/ZnS QDs were characterized by fluorescence spectroscopy, UV–vis spectrophotometry, transmission electron microscopy (TEM), Fourier transforms infrared (FTIR) and thermo-gravimetric (TG) analysis techniques. It was found that the fluorescence intensity of modified QDS (CdTe/ZnS-OS-g-PDMAEMA QDs) at 520 nm (excitation at 375 nm) was selectively quenched in the presence of trace amounts of TH drug. In this method, a simple, highly sensitive, selective and rapid analytical approach was used for the determination of TH in the concentration range of 9.14 × 10−9 mol L−1–7.23 × 10−6 mol L−1 with a detection limit of 2.74 × 10−9 mol L−1. The designed nano-sensor can be successfully applied for the determination of TH in complex matrixes (pharmaceutical formulations, urine, saline and glucose serums) with satisfactory analytical results.

Graphical abstract, Urgent identification of COVID-19 in infected patients is highly important nowadays. Förster or fluorescence resonance energy transfer (FRET) is a powerful and sensitive method for nanosensing applications, and quantum dots are essential materials in FRET-based nanosensors. The QDs are conjugated to DNA or RNA and used in many applications. Therefore, in the present study, novel fluorescence DNA-conjugated CdTe/ZnS quantum dots nanoprobe designed for detection of Covid-19 after extracting their RNA from saliva of hesitant people. For achieving this purpose, the water-soluble CdTe/ZnS QDs-DNA prepared via replacing the thioglycolic acid (TGA) on the surface of QDs with capture DNA (thiolated DNA) throw a ligand-exchange method. Subsequently, by adding the different concentrations of complementary (target DNA) in a mixture of quencher DNA (BHQ2-labeled DNA) and the QDs-DNA conjugates at different conditions, sandwiched hybrids were formed. The results showed that the fluorescence intensity was decreased with increasing the concentration of target DNA (as a positive control). The linear equation and regression (Y = 40.302 X + 1 and R2 = 0.98) were obtained by using the Stern-Volmer relationship. The Limit of detection (LOD) was determined 0.000823 µM. The achieved results well confirm the outcomes of the RT-PCR method in real samples.

Some chromeno[4′,3′-b]pyrano[6,5-b]quinoline derivatives were synthesized by condensation of 2-amino-4-aryl-3-cyano-5-oxo-4H, 5H -pyrano-[3,2-c] chromenes and 1,3-cyclohexanedione in an environmentally benign and efficient method by Cu(II)-Schiff base/SBA-15 as an environmentally friendly heterogeneous and recyclable catalyst under solvent-free conditions in high yields and rates. These kinds of catalysts are built from mesoporous silica SBA-15 which was covalently anchored with Cu(II) Schiff base complex. The shorter reaction times, good yields, simple work-up procedure and environmentally friendly conditions are the main advantages of this method compared to the last one. The product was identified by its 1H NMR, mass and IR spectra, which were compared to those reported previously.

Herein, we report a fast synthesis of 1,4-dihydropyridines, decahydroacridine-1,8-diones by one-pot multi-component reaction of 1,3-cyclohexanedione or dimidone, arylaldehydes, and ammonium acetate under solvent-less condition using Cu(II)-schiff base-SBA-15 as a reusable heterogeneous catalyst in high yields. These kinds of catalysts are built from mesoporous silica SBA-15 which was covalently anchored with Cu(II) schiff base complex. The shorter reaction times, good yields, simple work-up procedure and environmentally friendly conditions are the main advantages of this method compared to the last one. This method is also the first example of synthesizing acridines by Cu(II)-schiff base-SBA-15 as an efficient catalyst in solvent-free media which can be valuable to be used or investigated for similar systems. The product was identified by its 1H NMR, mass and IR spectra, which were compared to those reported previously.

Nanogels (NGs) are three-dimensional water soluble cross-linked hydrogel materials in the nanoscale size range with a high loading capacity for guest molecules and act as drug carrier systems. In the present work, a new type of thermo/pH sensitive NG comprising salep modified graphene oxide (SMGO) with branched N-isopropylacrylamide (NIPAM) and acrylic acid (AA) was prepared. The SMGO/P(NIPAM-co-AA) NGs exhibited nanoporous structure and spherical particles with diameters about 82nm as characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The samples were also characterized by Fourier transform infrared spectroscopy (FT-IR) and thermo gravimetric analysis (TGA) to further confirm about the formation of NGs. Doxorubicin (DOX) loaded SMGO/P(NIPAM-co-AA) NGs showed thermo/pH dependent releasing behavior: slow drug release at neutral pH and lower temperature but increased significantly in acidic pH and higher temperature, without any burst release. In addition, the NGs exhibited no effect on the cell viability in the tested concentration range up to 410μg/mL and drug release systems enhanced toxicity to HeLa cells when compared to the equivalent dose of the free drug. Overall, our results put forth NGs as potential candidates in the development of a new nanocarrier for anti-cancer drug delivery.

Current discovery of different modifications of multi walled carbon nanotubes has motivated research for their potential applications in various field such as adsorbent materials, and drug delivery. Many different modified carbon nanotubes have been achieved, including combinations with iron oxide nanoparticles (NPs) for their unique properties including magnetic properties, nontoxicity, biocompatibility and capability which have considerable impact on the delivery of the drug at the targeted area. However, one of the disadvantages of this nanocomposite in biological fluids is that iron oxide NPs might be quickly cleared by the bloodstream before realization of their targets. In order to overcome this obstacle, polymers could be used as stabilizer to achieve a highly stable NPs@MWCNT composite. As a result, a magnetic multi walled carbon nanotube hydrogel nanocomposite based on poly (acrylic acid) grafted onto salep was synthesized and then fully characterized by using FTIR spectroscopy, thermogravimetric analysis, EDAX spectrum, SEM, TEM, AFM images, and vibrating sample magnetometer (VSM) and synthesis mechanism was suggested. Besides, swelling kinetics and loading and releasing of tetracycline hydrochloride as a model drug in various conditions were also investigated.

A novel CdTe quantum dots (QDs) were prepared in aqueous phase via a facile method. At first, poly (acrylic amide) grafted onto sodium alginate (PAAm-g-SA) were successfully synthesized and then TGA capped CdTe QDs (CdTe-TGA QDs) were embed into it. The prepared CdTe-PAAm-g-SA QDs were optimized and characterized by transmission electron microscopy (TEM), thermo-gravimetric (TG) analysis, Fourier transform infrared (FT-IR), UV-vis and fluorescence spectroscopy. The characterization results indicated that CdTe-TGA QDs, with particles size of 2.90 nm, were uniformly dispersed on the chains of PAAm-g-SA biopolymer. CdTe-PAAm-g-SA QDs also exhibited excellent UV-vis absorption and high fluorescence intensity. To explore biological behavior of CdTe-PAAm-g-SA QDs, the interactions between CdTe-PAAm-g-SA QDs and human serum albumin (HSA) (or bovine serum albumin (BSA)) were investigated by cyclic voltammetry, FT-IR, UV-vis, and fluorescence spectroscopic. The results confirmed the formation of CdTe-PAAm-g-SA QDs-HSA (or BSA) complex with high binding affinities. The thermodynamic parameters (ΔG

We describe the synthesis of an end-functionalized fluorescent dye-labeled poly(N-(2-thiolethyl methacrylamide) as a metal chelating polymer with a very narrow size distribution and controllable molecular weights by reversible addition–fragmentation chain transfer polymerization. In following, we apply this water-soluble metal-chelating polymer for surface modification of cadmium telluride quantum dots (CdTe QDs) by ligand exchange method. The obtained poly(N-(2-thiolethyl methacrylamide)/CdTe QDs hybrid was fully characterized using Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TG) and transmission electron microscopy (TEM). The size of the prepared hybrid was estimated around 3.2 nm by TEM. Furthermore, we used this hybrid for improving the release performance of doxorubicin hydrochloride as a chemotherapeutic model drug. The in vitro release of doxorubicin was studied in pH 5.4 and 7.4, which release curves were nicely fitted by the Korsemeyer–Peppas equation and the release followed by non-Fickian diffusion or anomalous diffusion in pH 5.4. The synthesized fluorescent dye-labeled hybrid can be used as a donor-acceptor pair for fluorescence resonance energy transfer (FRET) experiments, so the energy transfer behavior between fluorescent dye as a donor and CdTe QDs as an acceptor were interrogated using Forster/fluorescence resonance energy transfer model, which the distance was found to be 3.95 nm. This present work has potential for both diagnostic and therapeutic aspects for cancer patients.

An efficient synthesis of novel ethyl-1,3,4-triphenyl-1H-pyrazolo[3,4-b]pyridine-6-carboxylate products has been achieved via condensation of pyrazole-5-amine derivatives and activated carbonyl groups, in refluxing acetic acid. This process has been found to be useful in the preparation of new N-fused heterocycle products in good to excellent yields.

A novel Schiff-base/SBA-15 nanoadsorbent was successfully synthesized by the reaction of salicylal- dehyde and (3-aminopropyl) trimethoxysilane in methanol and subsequent grafting with SBA-15. The morphology and structures of the as-synthesized Schiff-base/SBA-15 nanoadsorbent were characterized by powder X-ray dif- fraction, transmission electron microscopy, Fourier trans- form infrared spectroscopy, thermo-gravimetric analysis, and N2 adsorption/desorption isotherms. The obtained Schiff-base/SBA-15 nanoadsorbent was used for the removal of methylene blue (MB) from aqueous solutions. The effects of various parameters such as temperature, concentration, pH, and contact time were examined, and optimal experimental conditions were determined. The equilibrium isotherms were conducted using Freundlich and Langmuir models. The pseudo-first-order, pseudo- second-order, and intraparticle diffusion models were used to fit adsorption data in the kinetic studies. The thermo- dynamic parameters such as the standard enthalpy, stan- dard entropy, and standard free energy were evaluated. The obtained results indicated that the Schiff-base/SBA-15 nanoadsorbent is an efficient adsorbent for removing MB.

A novel, one-pot, simple, environmentally benign and efficient protocol has been employed for the synthesis of chromeno[4,3-b]quinoline derivatives in the presence of catalytic amounts of Cu(II)-Schiff base/SBA-15 under solvent-free conditions in excellent yields and rates.

The original version of this article unfortunately contained a mistake in the abstract. The sentence “To this aim, we first prepared poly [(N-isopropylacrylamide)-co-(2-dimethylamino ethyl methacrylate) nanogel by copolymerization processes and then added it into the solution of poly (2-dimethylamino ethyl methacrylate)] grafted onto salep” should read as “To this aim, we first prepared poly [(N-isopropylacrylamide)-co-(acrylic acid)] nanogel by copolymerization processes and then added it into the solution of poly (acrylic acid) grafted onto salep”.

New types of silver nanoparticles (Ag NPs) were prepared by the reduction of silver trifluoroacetate with diamine-sarcophagine (DiAmsar) in DMF solution. Nanoparticles growth, morphology, and chemical composition were determined by ultraviolet–visible spectroscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy, respectively. The effect of prepared Ag NPs on the fluorescence quenching of the dyes rhodamine 6G and 4-hydroxycoumarin were investigated in different temperatures. The results of the quenching experiments were analyzed using Stern–Volmer equation. The Stern–Volmer constant values showed that the quenching efficiencies decreased as the temperature increases indicating that the quenching process was a dynamic-type quenching. Moreover, the energy transfer behavior between Ag NPs and dye molecules were interrogated using Forster/fluorescence resonance energy transfer and nanomaterial surface energy transfer models. The anti-bacterial activities of Ag NPs were assessed against the Staphylococcus aureus and Escherichia coli bacteria. Results showed that the entitled Ag NPs have excellent antibacterial properties.

Cu(II)–DiAmSar complex functionalized mesoporous SBA-15 silica support was employed for the synthesis of benzothiazole heterocycles in aqueous media as a green solvent with excellent yields. The resulting novel catalyst is extraordinarily stable and inhibits leaching of the metal ions from the SBA-15 support. Furthermore, it showed good heterogeneous catalytic activity in the synthesis of the previously mentioned heterocycles and could also be recycled from the reaction mixture and reused six times. The nature of the support after the anchoring of Cu(II)–DiAmSar complex on the surface of SBA-15 nanochannels and successful anchoring were examined using X-ray diffraction, transmission electron microscopy, nitrogen physical adsorption, Fourier transform infrared studies and thermogravimetric analysis.

Zirconium(IV) oxide chloride was found to be a rapid and efficient catalyst for the synthesis of pyrazines and 2,3-disubstituted quinoxalines in water. A variety of pyridopyrazine and 2,3-disubstituted quinoxaline derivatives are readily prepared in high yields under green conditions by cyclocondensation of the desired 1,2-diamine and 1,2-diketone using a catalytic amount of zirconium(IV) oxide chloride in water. Less active diamines, such as 2,3- and 3,4-diaminopyridines took part in this protocol to provide the desired products in good to excellent yields.

A facile approach for surface passivation of water-soluble CdSe quantum dots (CdSe QDs) by new water-soluble multidentate biopolymer based on poly ((2-dimethylaminoethyl) methacrylate) grafted onto salep (salep-g-PDMA) is devised. The transmission electron micrographs (TEM) revealed an average size of 4.5 nm for QDs. The Fourier transform infrared spectra (FT-IR) were used to ascertain the functional groups of biopolymers on the surface of QDs. The obtained QDs samples showed significant improvement in their thermal behavior as indicated by thermo gravimetric analysis (TGA). The optimum conditions regarding to monomer concentration, CdSe/salep-g-PDMA ratio and temperature were obtained to achieve the highest FL intensity of the passivated QDs. Lastly, the in vitro antibacterial properties of the obtained optimum sample were investigated against gram-negative and gram-positive bacteria.

The ordered mesoporous silica SBA-15 was covalently anchored with copper (II) Schiff base complex to afford Cu(II)-Schiff base/SBA-15 catalyst. Powder X-ray diffraction, nitrogen adsorption–desorption analyses and TEM image confirm not only the retaining of support properties after anchoring but also the existence of void space in nanometer scale which result in good catalytic activity in the synthesis of pyridopyrazine and quinoxaline derivatives.

Novel silver/salep-g-poly(acrylic acid) nanocomposite hydrogel were prepared in aqueous solution using poly(acrylic acid) grafted onto salep as a biopolymer based material. FT-IR spectra confirmed that poly(acrylic acid) (PAA) had been grafted onto salep in graft copolymerization reaction. TEM observations showed that silver nanoparticles have been uniformly dispersed in polymeric matrix. Effects of pH, acrylic acid (AA) amount and silver ion concentration on swelling capabilities were investigated. Results indicate that modifying AA and silver ion can improve swelling properties of the resultant nanocomposite hydrogel. pH response of this nanocomposite hydrogel in acidic and neutral pH made it suitable for drug delivery applications.

A novel nano-porous hydrogel (NPH) was synthesized via graft copolymerization of sodium acrylate (Na-AA) and acrylamide (AAm) onto salep backbones and its application as a carrier matrix for oral delivery of tetracycline hydrochloride (TH) was investigated. The Taguchi method as a strong experimental design tool was used for synthesis optimization. The swelling behavior of optimum hydrogel was measured in various media. The hydrogel formation was confirmed by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetrical analysis (TGA). The study of the surface morphology of the hydrogels using SEM and AFM showed a nanoporous (average pore size: 180 nm) structure for the sample obtained under optimized conditions. The drug delivery results demonstrated that this NPH could successfully deliver a drug to the intestine without losing the drug in the stomach, and could be a good candidate as an orally administrated drug delivery system.

A new fluorescent composite based on CdS quantum dots immobilized on the multidentate biopolymer matrix is prepared through the graft copolymerization of the acrylamide onto kappa-Carrageenan. A variety of techniques like thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) was used to confirm the structure of the obtained samples. To investigate the spectrofluorometric properties, fluorescence spectroscopy of the obtained quantum dots was studied.

We report that sodium alginate and its graft-copolymers with (2-dimethylaminoethyl) methacrylate may attach to the surface of colloidal CdS–thioglycerol quantum dots (QDs) via a ligand exchange process and result in water-soluble and highly stable QD supramolecules. Optical properties of modified QDs in water showed that the emission intensity of QDs was still high after surface passivation.

A novel kind of a biopolymer-based superabsorbent composite, salep-g-poly(sodium acrylate)/alumina, was prepared from salep, sodium acrylate, and alumina by aqueous polymerization, using N,N′-methylenebisacrylamide (MBA) as a cross-linker and ammonium persulfate (APS) as an initiator. The reaction parameters [i.e., acrylic acid (AA), MBA, APS amounts, and neutralization percentage of AA as well as alumina/salep weight ratio] affecting the water absorbency of the hydrogel composite were optimized using systematic method to achieve a composite with high swelling capacity as possible. The swelling behavior of optimum superabsorbent composite was measured in various pH solutions. In addition, swelling kinetics, swelling in various NaCl concentrations, swelling in various solvents, and the absorbency underload were investigated. Also, pH-reversibility and the on–off switching behaviors of the composite in various environments were investigated. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 31: 41–51, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20233

In this work, CdSe quantum dots (CdSe QDs) were successfully synthesized and embedded in a biopolymer based on poly((2-dimethylaminoethyl) methacrylate) grafted onto kappa-Carrageenan (κC) via a facile process. The synthesized samples were studied by transmission electron microscopy (TEM) and it showed that the CdSe quantum dots have an average size of around 3.5 nm which were dispersed in the biopolymer matrix. Fourier transform infrared spectrum (FT-IR) was used to characterize the functional groups on the surface of QDs and the structure of biopolymer samples. UV–vis and FL spectra were employed to study the optical properties of QDs before and after ligand exchange with modified κ-Carrageenan biopolymers. The obtained samples showed significant improvement in their thermal behavior as indicated by thermo gravimetric analysis (TGA). Lastly, the effect of some factors on the fluorescent properties of CdSe quantum dots has been investigated to obtain QDs with highest fluorescent intensities.

In this report, a rapid, efficient and environmental friendly synthesis of 3-carboxycoumarins under ultrasound irradiation in water media is described. The Knoevenagel condensation of Meldrum’s acid with substituted benzaldehydes in the presence of zirconium oxide chloride (ZrOCl2·8H2O) and ultrasonic irradiation in water gave the corresponding 3-carboxycoumarins in good to excellent yields.

The synthesis of a novel superabsorbent hydrogel with natural hybrid backbone via graft copolymerization of acrylamide (AAm) onto kappa-carrageenan (kC, as a polysaccharide) and gelatin (as a protein) under classic thermal conditions is described. The Taguchi method as a strong experimental design tool was used for synthesis optimization. A series of hydrogels were synthesized by proposed conditions of Qualitek-4 Software. Considering the results of 9 trials according to analysis of variance (ANOVA), optimum conditions were proposed. The swelling behavior of optimum hydrogel was measured in various solutions with pH values ranging from 1 to 13. In addition, swelling kinetics, swelling in various organic solvents, various salt solutions and On–Off switching behavior were investigated. The hydrogel formation was confirmed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetrical analysis (TGA). Surface morphology of the synthesized hydrogels was assessed by scanning electron microscope (SEM).

In this report, the synthesis of a novel superabsorbent hydrogel via γ-irradiation graft copolymerization of acrylamide onto sodium alginate and kappa-carrageenan hybrid backbones in a homogeneous solution is described. The Taguchi method was used as a powerful experimental design tool for synthesis optimization. A series of superabsorbent hydrogels was synthesized by proposed conditions of Qualitek-4 software. Considering the results of nine trials according to analysis of variance, optimum conditions were proposed. The swelling behavior of optimum superabsorbent hydrogels was studied in various solutions, with pH values ranging from 1 to 13. In addition, swelling kinetics, swelling in various organic solvents, the absorbency under load, and on–off switching behavior were investigated. Also, hydrogel formation was confirmed by Fourier transform infrared spectroscopy. Surface morphology of the synthesized hydrogels was assessed by scanning electron microscopy. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 28:131–140, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20154

A simple, fast and efficient benign procedure has been developed for one-pot synthesis of 2-substituted benzothiazoles in the presence of zirconium(IV) oxide chloride octahydrate (ZrOCl2·8H2O) and anhydrous copper(II) sulfate. The reaction of 2-aminothiophenol with aldehydes and anhydrides was carried out efficiently in solvent-free conditions with or without microwave irradiation, and adducts were produced in good to excellent yields. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:136–141, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20191

In the title molecular structure, C14H15NO4, all non-H atoms, except for the C atoms of the terminal methyl groups of the diethylamino substituents, are essentially coplanar. In the crystal structure, a two-dimensional network is formed via weak intermolecular C—H...O hydrogen bonds and π–π stacking interactions.

In the title molecular structure, C18H18N2O6·CHCl3, the dihedral angle between the two fused, essentially planar, six-membered rings is 5.4 (2)°. In the crystal structure, weak intermolecular C—H...O hydrogen bonds and π–π stacking interactions connect molecules into two-dimensional layers.

The asymmetric unit of the title compound, C(8)H(6)N(4), contains two almost planar independent mol-ecules (r.m.s. deviations = 0.026 and 0.030 Å). The crystal studied was a non-merohedral twin with the components in a 0.513 (2):0.487 (2) ratio.

We report a simple, fast, efficient and benign procedure for solvent-free microwave-assisted one-pot synthesis of symmetrical 4H-pyran-4-ones in the presence of polyphosphoric acid or diphosphorous pentoxide. Various 4H-pyran-4-ones were prepared using this very simple and fast green protocol. Descrevemos um procedimento simples, rápido, eficiente e benigno para a síntese assistida por microondas, sem o uso de solvente, de 4-piranonas simétricas na presença de ácido polifosfórico ou pentóxido de fósforo. Diversas 4-piranonas foram preparadas por esse método simples e rápido.

In the title molecule, C15H11NO7, the dihedral angle between the coumarin unit and the succinimide unit is 72.36 (4)°. The crystal structure is stabilized by weak intermolecular C—H...O hydrogen bonds and π–π stacking interactions.

In the title molecule, C11H8O5, the non-H atoms of the coumarin unit are essentially coplanar; the methoxy and carboxylate groups form dihedral angles of 6.5 (4) and 6.7 (4)°, respectively, with this group. In the crystal structure, weak intermolecular C—H...O hydrogen bonds form chains of rings propagating in the [210] direction.

A facile procedure for the coating of CdTe quantum dots (QDs) by a natural biopolymer based on polyacrylamide (PAAm) grafted onto kappa-carrageenan (κC-g-PAAm) is introduced. Transmission electron microscopy images revealed that the QDs are nearly spherical in shape with average diameter of ~2.4 nm. The optical property of QDs was studied by the UV-visible spectrum. The biomolecules were used to investigate their influence on the fluorescence intensity of nanocrystals. Fourier transform infrared spectroscopy study suggested QDs can interact with functional groups of biopolymer including its hydroxy and amide groups.