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An inexpensive, air-moisture stable and reusable PS–Pd(II)-furfural complex was synthesized by reacting polymeric amine with furfural to get polymer anchored ligand which was then reacted with Pd(OAc) 2 to get polymer anchored complex. This complex was characterized by different spectroscopic and elemental analyses. The activities of the Pd-complex were tested for the C C and C N cross-coupling reactions under various reaction conditions. The catalyst exhibits high catalytic activities for the coupling of various aryl halides with organoboronic acid, alkene, alkyne and amine providing excellent yields of desired product. Further, the catalyst can be easily recovered by simple filtration and reused up to five times without significant loss of its catalytic activity.

A new polymer-anchored Cu(II) complex has been tested for the oxidation of sulfides and in oxidative bromination reaction with hydrogen peroxide as oxidant. Sulfides have been selectively oxidized to corresponding sulfoxides in excellent yields and in presence of KBr as bromine source, organic substrates have been selectively converted to mono bromo substituted compounds. The polymer-anchored Cu(II) catalyst could be easily recovered by simple filtration and reused more than six times without appreciable loss of its initial activity.

Polymer-anchored azo complexes of Cu(II) and Ni(II) were synthesized by the reaction of chloromethylated polystyrene, 3-aminophenol, and 1-nitroso-2-naphthol with the metal chlorides. The catalytic activities of these complexes were studied in the oxidation of various organic substrates including alkenes, alcohols, alkanes, and sulfides with 30 % aqueous hydrogen peroxide. The structures of both catalysts have been investigated by physiochemical methods. Both catalysts proved to be very stable and could be reused more than five times without significant loss of activity. Furthermore, these catalysts require very mild reaction conditions.

A new reusable polymer anchored Cu(II) complex was synthesized which can acts as an efficient heterogeneous catalyst for oxidation of olefins and alcohols with tert -butylhydroperoxide (TBHP) in aqueous medium. The present catalyst well oxidized styrene and other olefins to their allylic products and alcohols were converted to their corresponding aldehydes in good-to-moderate yields. This catalyst can be easily recovered by filtration and recycled without significant loss of its catalytic performances.

A new polymer-anchored Pd(II) Schiff base complex has been prepared and characterized using scanning electron microscopy, elemental analysis, atomic absorption spectroscopy, TGA and spectrometric methods such as diffuse reflectance spectra of solid and FT-IR spectroscopy. This polymer-anchored palladium catalyst shows excellent catalytic activity in the liquid-phase hydrogenation reaction of styrene oxide to obtain selectively 2-phenylethanol at normal pressure of hydrogen gas (1 atm.) at room temperature in DMF medium. We have also studied the liquid-phase hydrogenation reaction of various organic substrates. The catalyst exhibits excellent catalytic activity for the Suzuki cross-coupling of various substituted and non-substituted aryl halides. The influences of various parameters were investigated to optimize reaction conditions. The reusability experiments show that the catalyst can be used five times without much loss in catalytic activity. Copyright © 2012 John Wiley & Sons, Ltd.

Polymer anchored oxovanadium catalyst was synthesized and characterized. The solid catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), UV–vis diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). Its catalytic activity was evaluated for the oxidation of various alkenes, sulfides and aromatic alcohols with 30% H2O2 under mild reaction conditions. This catalyst was also effective for the oxidative bromination reaction of organic substrates with 80–100% selectivity of mono substituted products with H2O2/KBr at room temperature. The above reactions require minimum amount of H2O2, short time period and most importantly all the above reactions occur in aqueous medium. The developed catalyst can be facilely recovered and reused six times without significant decrease in activity and selectivity. This result confirms that the polymer anchored complex was not leached during the reaction, suggesting the true heterogeneous nature of the catalyst.

Three homogeneous Cu(II), Co(II) and Ni(II) complexes of a Schiff base ligand and their heterogeneous complexes supported on poly(4-aminostyrene) were prepared and characterized by using elemental analysis, fourier transform infrared spectroscopy, UV–Vis diffuse reflectance spectroscopy, thermogravimetric analysis and scanning electron microscopy. The catalytic performance of both homogeneous and heterogeneous complexes was evaluated in the liquid phase oxidation of cyclohexene, styrene and trans-stilbene in acetonitrile with tert-butylhydroperoxide or hydrogen peroxide as the oxidant. All types of catalyst were active in oxidation; and, the complexes produce allylic oxidation products in all cases. Immobilized complexes are slightly more active than their homogeneous complexes. The polymer-supported Cu(II) complex shows a higher catalytic activity than the other metal species. The activities of the immobilized catalysts remained nearly the same after five cycles, suggesting the true heterogeneous nature of the catalyst.

A simple and industrially viable protocol for C–N and C–O coupling was reported here. The polymer supported heterogeneous copper catalyst was prepared from chloromethyl polystyrene using a simple procedure. O-Arylation of substituted phenols with various aryl halides was achieved using this copper catalyst in DMSO medium. This heterogeneous copper catalyst, also efficiently works for the N-arylation of N–H heterocycles with aryboronic acids in methanol. This catalyst was also effective in amination reaction of primary amines with aryl halides as well as arylboronic acids in DMSO medium. The effects of solvent, base and temperature for the O-Arylation and amination reactions were reported. Further, the catalyst can be easily recovered quantitatively by simple filtration and reused up to several times without sufficient loss of its catalytic activity.

A tetradentate Schiff base (teta), obtained from triethylenetetramine and salicylaldehyde, has been covalently bonded to divinylbenzene cross-linked chloromethylated polystyrene. This chelating ligand, abbreviated as PS-teta (PS = polymeric support), reacts with metal chlorides (Cu2+, Co2+, and Ni2+) in methanol to give polymer-bound transition metal complexes, PS-Cu(II)teta/(Cat-1), PS-Ni(II)teta/(Cat-2), and PS-Co(II)teta/(Cat-3), formation of which has been established by various physiochemical methods and spectroscopic techniques. The catalytic potential of these materials has been tested for the oxidation of various alkenes, alkanes, alcohols, and thioethers in the presence of 30% H2O2 as an oxidant. At the same time, these catalysts are very stable and could be reused in oxidation reactions for more than five times without noticeable loss of their catalytic activity.

A polymer-anchored nickel(II)–phenanthroline complex [polyNi(II)–phen] was synthesized and used effectively as a reusable catalyst in various oxidation reactions in the presence of tert-butylhydroperoxide as an oxidant in acetonitrile medium. The catalyst was characterized with elemental analysis, atomic absorption spectrometry (AAS), thermogravimetric analysis, scanning electron microscopy, and spectrometric methods such as diffuse reflectance spectroscopy, ultraviolet–visible spectroscopy, and Fourier transform infrared spectroscopy. The study of the effects of the time, temperature, oxidant, catalyst concentration, molar ratio of substrate to oxidant, and solvent in the oxidation of styrene individually gave the optimized reaction conditions. Under optimized conditions, the catalyst exhibited good conversions for the oxidation reactions of various olefins, alkanes, aromatic alcohols, and thioethers. The catalyst was easily recovered by simple filtration and reused for more than five times with consistent catalytic activity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A new polymer-supported Cu(II) Schiff base complex has been synthesized and characterized by elemental (including metal) analysis, FT-IR spectroscopy, UV–Vis diffuse reflectance spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The catalytic performance of this complex was evaluated in the epoxidation of styrene in acetonitrile/N,N-dimethylformamide (9:1) mixture with 70% tert-butyl hydroperoxide as an oxidizing agent under liquid phase reaction conditions for selective synthesis of styrene oxide. Suitable reaction conditions have been optimized by considering the effects of various reaction parameters such as temperature, reaction time, solvent, oxidant, catalyst amount, and styrene to hydroperoxide molar ratio for the maximum conversion of styrene as well as selectivity of styrene oxide. We have also investigated the epoxidation reaction of various olefins under the optimized reaction conditions. Comparison between catalytic activities of the polymer-supported Cu(II) Schiff base complex and its homogeneous analogue showed that the polymer-supported catalyst was more active. This heterogeneous complex was reused for five times. The selectivity of the heterogeneous catalyst does not change even after five times of reusing.

The Ullmann coupling of amines with aryl iodide as well as arylboronic acids and N(H)-heterocycles with arylboronic acids has been carried out efficiently using PS-LCu(I) catalyst. The copper complex has been prepared and characterized by using scanning electron microscope (SEM), elemental analysis, atomic absorption spectroscopy (AAS), Thermo gravimetric analysis and spectrometric methods like Fourier transform infrared spectroscopy (FTIR). The effects of various parameters such as temperature, solvent and base on the reaction system were studied. The reusability experiments show that the catalyst can be used five times without much loss in the catalytic activity.

Polymer supported Cu(II) catalyst was prepared, characterized and employed for the N-arylation and amination reaction of N–H heterocycles with aryl halides as well as arylboronic acids to afford the corresponding coupled products in good to excellent yields. This catalyst can be used several times with consistent catalytic activity. R1 = H, Me, OMe, COMe, NO2; R2 = H, Me, OMe, Cl, F, CF3, NO2.

Immobilization of copper onto polystyrene provided a polymer-supported copper(II) catalyst, which was effective in cross-coupling reactions between N-containing substrates and arylboronic acids using methanol as a solvent in air under base-free conditions. This catalyst was also effective in N-arylation of imidazole with aryl halides in DMSO using K2CO3 as a base under nitrogen atmosphere. The catalyst was characterized by physico-chemical and spectroscopic techniques. The product N-arylimidazoles and N-arylbenzimidazoles were isolated in good to excellent yields. This copper catalyst was air stable and could be recycled with minimal loss of activity.

The coupling between aryl halides with terminal alkenes (Heck reaction) has been investigated in the presence of a polystyrene-supported Schiff base palladium(II) catalyst. The present catalyst is air and moisture-stable and has significant catalytic activity in Heck cross-coupling reactions under operating conditions. Various aryl halides and terminal alkenes were coupled smoothly under air, to afford the corresponding cross-coupled products in excellent yields. Furthermore, the catalyst can be easily recovered quantitatively by simple filtration and reused up to seven cycles without losing its activity. O acoplamento entre haletos de arila e terminais alceno (reação de Heck) foi investigado na presença de catalisadores de paládio (II) suportados em poliestirenos contendo bases de Schiff. O catalisador é estável frente ao ar e umidade, e tem atividade catalítica significativa nas reações de acoplamento cruzado de Heck sob condições normais. Vários haletos de arila e alcenos terminais foram facilmente acoplados na presença de ar, fornecendo os correspondentes produtos de acoplamaneto cruzado, em ótimos rendimentos. O catalisador é facilmente recuperado quantitativamente por filtração simples e reutilizado por até sete ciclos sem perda de atividade.

A new polymer supported Cu(II) Schiff base complex was synthesized. The solid complex was characterized by Fourier transform infrared spectroscopy (FT-IR), UV–vis diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). Its homogeneous analogue was also prepared. The catalytic performances of the copper complex in oxidation reactions were evaluated for both homogeneous and heterogeneous systems. The copper(II) complex was found to be efficient catalyst for the oxidation of alkenes, alkanes and aromatic alcohols in the presence of hydrogen peroxide as oxidant at room temperature. The catalytic investigation revealed that the solid complex performs better than the homogeneous one as an oxidation catalyst. The solids containing the immobilized complex can be recovered from the reaction medium and reused almost five times, maintaining good catalytic activity. Furthermore, the in vitro toxicity of the ligand and complex was tested against the growth of bacterial species, viz., Staphylococcus aureus and Escherichia coli .

A thiosemicarbazone Cu(II) complex anchored to a polystyrene framework has been synthesized and characterized by analytical and spectroscopic techniques. The complex was found to be a highly active catalyst for the oxidation of various organic substrates including alkenes and alcohols using H2O2 as oxidant. The reaction conditions were optimized with respect to temperature, solvent, oxidant, catalyst amount, and substrate to peroxide ratio. The heterogeneous catalyst was reused five times without significant loss of activity. A comparison between the catalytic activities of this polymer-supported Cu(II) complex and its homogeneous analogue was carried out.

Three polymer-anchored metal complexes (Co, Cu, and Pd) were synthesized and characterized. The catalytic performance of these complexes was tested for the oxidation of olefins and aromatic alcohols. These complexes showed excellent catalytic activity and high selectivity. These complexes selectively gave epoxides and aldehydes from olefins and alcohols, respectively. Individually, the effect of various solvents, oxidants, substrate oxidant molar ratios, temperatures, and catalyst amounts for the oxidation of cyclohexene and benzyl alcohol were studied. Under optimized reaction conditions, 96, 81, and 71% conversions of cyclohexene and 86, 79, and 73% conversions of benzyl alcohol were obtained with Co(II), Cu(II), and Pd(II) catalysts, respectively. The catalytic results reveal that these complexes could be recycled more than five times without much loss in activity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Selective oxidation of olefins has been carried out in water medium with tert-butylhydroperoxide (TBHP, 70% aqueous) as an oxidant using polymer-anchored Ni(II) complex as a catalyst. Several parameters were varied to optimize the reac-tion conditions. Under the optimized reaction conditions olefins gave selectively allylic oxidation products. The present polymer anchored Ni(II) complex can be recycled five times without any appreciable loss in catalytic activity.

The hydroformylation reaction is an important class of reaction as it enhances the carbon chain length of an olefin molecule. RhI complexes are conventionally used as the catalyst for this reaction although they possess severe drawbacks with respect to separation and recycling. A phenyl-functionalised 2D-hexagonal mesoporous silica material has been synthesised by a surfactant templating pathway. The phenyl group of this mesoporous material was functionalised through nitration, followed by its reduction to the amine derivative. The amine group was further subjected to Schiff-base condensation, and the RhI complex was then heterogenised over its surface to yield the ortho-metallated complex anchored on the mesoporous silica matrix. The materials have been characterised by using powder X-ray diffraction, transmission electron microscopy and nitrogen adsorption/desorption studies. The RhI-loaded mesoporous material acts as a very efficient catalyst for the hydroformylation reaction of 1-hexene and exhibits high selectivity towards the formation of n-heptanal at 343 K in the presence of H2/CO at 50 bar pressure.

Two copper complexes were synthesized from macroporous chloromethylated polystyrene beads. The first one was prepared by sequential attachment of imidazole and copper acetate with chloromethylated polystyrene-divinyl benzene copolymer, and the second one was prepared from 4-vinylpyridine and copper acetate with chloromethylated polystyrene-divinyl benzene copolymer. These catalysts showed excellent catalytic activity in O-arylation reaction of aryl halides with phenol in dimethylsulfoxide using potassium carbonate at 130 °C under open air conditions to give diaryl ethers in high yields. Less reactive aryl bromides and aryl chlorides have also been shown to react with phenols to give good yields of the diaryl ethers. The effects of various parameters such as solvent, catalyst from different copper salt and base on the reaction system were studied. The reaction is applicable to a wide variety of substituted aryl halides and phenols with different steric and electronic properties. These catalysts were recovered by simple filtration, and the reusability experiments showed that these catalysts can be used five times without much loss in the catalytic activity.

An inexpensive, air–moisture stable and reusable PS–Pd(II)–anthra complex was synthesized by reacting chloro-methylated polystyrene with anthranilic acid to get polymer anchored ligand which was then reacted with PdCl 2 to get polymer anchored complex. This complex was characterized by different spectroscopic and elemental analyses. The activity of the Pd-complex as catalyst was tested for the Suzuki, Heck, Sonogashira cross-coupling and also for amination and cyanation reactions under various conditions. The catalyst exhibits high catalytic activities for the coupling of various aryl halides with organoboronic acid, alkene, alkyne and amine along with the cyanation of aryl halides providing excellent yields of desired product. Further, the catalyst can be easily recovered quantitatively by simple filtration and reused up to five times without sufficient loss of its catalytic activity.

The polymer-anchored Schiff base complexes of Cu(II), Co(II), Ni(II), Mn(II) and Fe(III) were prepared by reacting polystyrene amine with 2-pyridinecarbaldehyde followed by loading of metal atom in methanol. These complexes were characterized by using different physico-chemical and spectroscopic methods. The catalytic activity of these polymer-supported metal catalysts was tested for the oxidation of various olefins and alcohols. Influence of various reaction parameters, such as reaction temperature, reaction time, oxidant, substrate-to-oxidant mole ratio and nature of solvent, was studied for the oxidation of cyclohexene with these catalysts. Among the catalysts studied, Cu-Cat showed higher catalytic activity toward oxidation reactions than the other catalysts. Moreover, hot filtration experiments proved that these catalysts are truly heterogeneous and can be reused a number of times without significant loss of activity.

A new heterogeneous secondary amine Pd(II) complex anchored to macroporous polystyrene beads, P-[Pd2(seam)2(OAc)2] (seam = secondary amine), was synthesized by reacting polymer-anchored secondary amine with palladium acetate in acetic acid medium. The structure of this immobilized complex has been established on the basis of scanning electron microscope, thermogravimetric analysis, elemental analysis, atomic absorption spectroscopy, and spectrometric methods like diffuse reflectance spectra of solid and Fourier transform infrared spectroscopy. The catalytic activity of the Pd-complex was investigated toward the oxidation of various olefins and alcohols in presence of tert-butylhydroperoxide as an oxidant. The effects of various parameters such as solvent, oxidant, reaction time, reaction temperature, amount of catalyst, and substrates-to-oxidant ratio have been studied. The catalytic results reveal that the present polymer-anchored Pd(II) complex can be recycled more than seven times without much loss in the catalytic activity. Comparative studies have been done with the corresponding unsupported metal complex. The polymer-anchored catalyst was found to be superior to its homogeneous counterpart in activity, product selectivity, stability, and reusability © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

BACKGROUND: Precise architectures of steric and electronic properties of palladium species play a crucial role in designing highly functionalized catalyst systems responsible for target organic transformations. Pd catalysts supported on polymer materials have been employed extensively as catalysts not only for hydrogenation but also for coupling reactions in the production of fine chemicals. RESULTS: A new polymer-anchored Pd(II) complex has been synthesized and characterized. The catalyst shows high catalytic activity in the hydrogenation of styrene oxide, Heck cross-coupling and cyanation reactions of aryl halides. The effect of various reaction parameters were investigated to optimize reaction conditions. The catalytic system shows good activity in the hydrogenation of styrene oxide (conversion 98%) with a selectivity to 2-phenylethanol (93%) which is higher than its homogeneous analogues. The catalyst also exhibits excellent catalytic activity for the Heck cross-coupling and cyanation reactions of various substituted and non-substituted aryl halides. CONCLUSIONS: Results demonstrate that the catalyst is robust and stable and can be recovered quantitatively by simple filtration and reused several times without loss of activity. Copyright © 2010 Society of Chemical Industry

Poly(3,6-dibenzaldimino-N-vinylcarbazole)-anchored palladium(II) complex has been synthesized and characterized by different physicochemical and spectroscopic techniques. The present complex shows excellent catalytic activities for Suzuki and Sonogashira coupling reactions under phosphine-free and copper-free reaction conditions in water medium. This immobilized catalyst can be easily separated and reused for further reactions for more than five times without noticeable loss in the catalytic activity.

A novel pathway for cross-coupling reaction of terminal alkenes with aryl halides (Heck cross-coupling) has been described using a new phosphine-free poly(N-vinyl carbazole) anchored palladium(II) complex as catalyst in aerobic conditions. The catalyst was found to be highly active for the couplings of a variety of substituted and non-substituted aryl halides with terminal alkenes and to smoothly afford the corresponding desired products in good to excellent yields. The catalyst can be reused at least six times without noticeable decrease in catalytic activity.

A new polystyrene anchored Pd(II) azo complex has been synthesized and characterized. The present Pd(II) azo complex behaves as a very efficient heterogeneous catalyst in the Suzuki coupling and Sonogashira coupling reaction in water medium. Aryl halides, coupled with phenylboronic acids (Suzuki–Miyaura reaction) or terminal alkyne (Sonogashira reaction), smoothly afford the corresponding cross-coupling products in excellent yields (83–100% yield for Suzuki reaction and 68–96% yield for Sonogashira reaction of aryl halides) under phosphine-free reaction conditions in the presence of polystyrene anchored Pd(II) azo complex catalyst in water medium. Furthermore, the catalyst has shown good thermal stability and recyclability. This polymer-supported Pd(II) catalyst could be easily recovered by simple filtration of the reaction mixture and reused for more than six consecutive trials without a significant loss of its catalytic activity.

Immobilisation of copper acetate onto a modified polystyrene provided a polymer-supported copper(II) Schiff base catalyst, which is effective in the O-arylation reaction of phenols with aryl halides to give diaryl ethers in high yields. This catalyst is air-stable and was recycled for five times with minimal loss of activity.

A poly(3,6-dibenzaldimino N-vinyl carbazole) Pd(II) complex has been synthesized and characterized by physicochemical and spectroscopic techniques. The complex was found to be highly active toward hydrogenation reactions of various organic substrates under atmospheric pressure at ambient temperature. A tentative reaction mechanism is proposed on the basis of kinetic studies and isolation of reactive intermediates. The catalyst shows good conversion rates, thermal stability and recyclability.

A polymer-anchored Pd(II) Schiff base complex has been synthesized by reacting a polymeric amine with 2-pyridinecarboxaldehyde to get the polymer-anchored Schiff base, which was then reacted with palladium acetate. The catalyst was characterized by physicochemical and spectroscopic methods. It shows excellent catalytic activity in the Sonogashira coupling of phenylacetylene with aryl halides using triethylamine as a base and copper iodide as a co-catalyst in water under open air at 70 °C. We have also studied the effects of base and solvent on the coupling reaction. Sonogashira reactions of phenylacetylene with a variety of functionalized aryl halides were performed under the optimized reaction conditions. This catalyst gives excellent yields without the use of phosphine ligands. Further experiments showed that the catalyst can be used five times without much loss in the catalytic activity.

Four different types of commercially available silica nanoparticles were added to ordinary portland cement pastes to study their effects. The subsequent multiscale characterization of the material revealed that the addition of the nanoparticles induced a pozzolanic reaction that increased the amount of calcium silicate hydrate (C-S-H) gel in the paste to the detriment of portlandite. This had important implications for the hydration kinetics and the microstructure of the paste, including an increase in the initial hydration rate. A reduction of the overall porosity was also observed. The C-S-H gel of the pastes with nanosilica also showed some particular features, such as greater aluminum content and longer silicate chains. This was especially relevant because nanoindentation measurements and atomistic calculations showed that this was bound to an improvement in the mechanical properties of the C-S-H gel itself. Finally, the sum of all these factors resulted in pastes with 30% more compressive strength, which proved that, effectively, small changes can make a great difference.

It is well recognized that the use of mineral admixtures such as silica fume enhances the strength and durability of concrete. This research compares the effects of adding silica fume and nanosilica to concrete and provides a better understanding of the changes in the concrete nanostructure. Nanoindentation with scanning probe microscopy imaging was used to measure the local mechanical properties of cement pastes with 0% and 15% replacement of cement with silica fume. A reduction in the volume fraction of calcium hydroxide in a sample with silica fume provides evidence of pozzolanic reaction. Furthermore, replacing 15% cement by silica fume increased the volume fraction of the high-stiffness calcium silicate hydrate (C-S-H) by a small percentage that was comparable with the decrease in the volume fraction of calcium hydroxide. A parallel study of cement pastes with nanosilica showed that nanosilica significantly improves durability of concrete. This research provides insight into the effects of nanosilica on cement paste nanostructure and explains its effect on durability of concrete. The nanoindentation study showed that the volume fraction of the high-stiffness C-S-H gel increased significantly with addition of nanosilica. Nanoindentation results of cement paste samples with similar percentages of silica fume and nanosilica were compared. Samples with nanosilica had almost twice the amount of high-stiffness C-S-H as the samples with silica fume.

A new polymer anchored copper(II) azo complex has been synthesized and characterized by using scanning electron microscope (SEM), thermogravimetric analysis (TGA), elemental analysis, atomic absorption spectroscopy (AAS) and spectrometric methods like diffuse reflectance spectra of solid (DRS) and Fourier transform infrared spectroscopy (FTIR). The immobilized Cu(II) catalyst shows excellent catalytic activity in oxidation of cyclohexene, styrene, benzyl alcohol and ethylbenzene in presence of tert-butylhydroperoxide (TBHP) as an oxidant. The effects of different solvents, oxidants, temperature, substrate oxidant ratio and amount of catalyst were also studied. The catalytic results reveal that the polymer-anchored Cu(II) azo complex catalyst can be recycled more than five times without appreciable loss in the catalytic activity.

A new heterogeneous Schiff base copper(II) complex was prepared by reacting amino-polystyrene with salicylaldehyde followed by complexation with cupric chloride. The structure of this immobilized complex has been established on the basis of scanning electron microscope (SEM), thermogravimetric analysis (TGA), elemental analysis employing atomic absorption spectroscopy (AAS), and spectrometric methods like diffuse reflectance spectra of solid (DRS) and fourier transform infrared spectroscopy (FTIR). Catalytic activity of this polymer anchored Cu(II) complex was tested by studying the oxidation of cyclohexene, styrene, and benzyl alcohol in the presence of tert- butylhydroperoxide as oxidant. Several parameters such as solvent, oxidant, reaction time, reaction temperature, amount of catalyst, and substrates oxidant ratio were varied to optimize the reaction condition. Under optimized reaction conditions, cyclohexene gave a maximum of 74% conversion with three major products 2-cyclohexene-1-one, cyclohexene epoxide, and 2-cyclohexene-1-ol. The conversions of styrene and benzylalcohol proceed with 53% and 77%, respectively. Styrene gives styrene epoxide as the major product while benzylalcohol gives benzaldehyde as the major product. The catalytic results reveal that polymer anchored copper(II) Schiff base complex can be recycled more than five times without much loss in the catalytic activity. Copyright © 2009 John Wiley & Sons, Ltd.

Researchers at the University of Connecticut have been working with researchers at the Connecticut Department of Transportation to develop and implement continuous bridge monitoring systems on a series of bridges in Connecticut. The monitoring systems are designed to evaluate the long-term behavior of the bridges and to evaluate safety and reliability to ensure that no major structural changes could lead to significant problems. The approach used to organize the large amount of data that are collected from the first three bridges in the project is described. The goal of this work is to facilitate the continuous evaluation of the bridge network and thus assist those responsible for the management and safety of Connecticut's bridge infrastructure.

Calcium sulfoaluminate (CSA) cements were developed for shrinkage compensation of concrete. This study investigates the expansion characteristics of CSA-portland cement (CSA-OPC) systems in the presence of mineral admixtures (MA). Unrestrained expansion of CSA-based cement pastes incorporating Class C fly ash (FA), Class F FA, and silica fume (SF) were monitored at water-cementitious material ratios (w/cm) of 0.34 and 0.44. Despite the same amount of expansive component, CSA-OPC-MA mixtures exhibited noticeable difference in expansion. The Class F FA increased the unrestrained expansion at early age for both w/cm, which was attributed to lower material resistance (that is, stiffness) due to the presence of Class F FA. Furthermore, the expansion of the Class C FA-based mixture ceased at 2 days at both w/cm due to faster consumption of ye'elimite. A calorimetric study of Class C FA-based mixture revealed early depletion of sulfates, which correlated well with the completion time of expansion. Additionally, the presence of SF lowered the expansion, which was attributed to the lower alkalinity of pore solution, incomplete hydration of ye'elimite, and increased material stiffness.

This research studied the effects of surfactants on graphene nanoplatelet (GNP) dispersion in water. Samples consisted of water, GNPs, and varied amounts of water reducing admixture (WRA). The GNPs were added at a fixed 0.2 % by weight of water while the amount of WRA used served as the independent variable. Sedimentation was qualitatively characterized by observing the rate at which GNPs settled out of suspension. Scanning Electron Microscopy (SEM) was used to obtain micrographs of the dried GNPs. The time evolution of light transmission through the supernatant region was measured with ultraviolet-visible spectroscopy (UV/Vis). Improved understanding and control of GNP dispersion in water has the potential to facilitate the beneficial use of this and similar materials in composites for resulting beneficial mechanical and electrical properties.

A new heterogeneous graphene based catalyst with silver nanoparticles is developed and successfully applied as catalyst for the three component condensation of aldehydes, terminal alkynes, and amines as well as the 1,3-dipolar cycloaddition of organic azides with terminal alkynes.

A new polystyrene-anchored palladium(II) catalyst has been prepared and characterized by conventional spectroscopic methods and elemental analyses. The catalyst was found to be highly effective for...

Carbon nanotubes (CNTs) have the potential to enhance the strength, toughness, and multifunctional ability of composite materials. However, suitable dispersion and interfacial bonding remain as key challenges. Composites that are formed by reactions with water, like Portland cement concrete and mortar, pose a special challenge for dispersing the inherently hydrophobic nanotubes. The hydration of Portland cement also offers a specific chemical framework for interfacial bonding. In this study, nanoscale silica functional groups are covalently bonded to CNTs to improve their dispersion in water while providing interfacial bond sites for the proposed matrix material. The bond signatures of treated nanotubes are characterized using Fourier transform infrared spectroscopy. In situ dispersion is characterized using cryogenic transmission electron microscopy and point of zero charge (PZC) measurements. At the nanoscale, interparticle spacing was greatly increased. A slight increase in the PZC after treatment indicates the importance of steric effects in the dispersion mechanism. Overall, results indicate successful functionalization and dramatically improved dispersion stability in water.

A new polystyrene-supported Cu(II) Schiff base complex is synthesized, which shows high catalytic activity in the epoxidation of both linear and cyclic olefins.

A new polymer-anchored Cu(II) complex has been synthesized and characterized. The catalytic performance of the complex has been tested for the oxidation of sulfides and in oxidative bromination reaction with hydrogen peroxide as the oxidant. Sulfides have been selectively oxidized to the corresponding sulfoxides in excellent yields and in the presence of KBr as the bromine source, organic substrates have been selectively converted to mono bromo substituted compounds using polymer-anchored Cu(II) catalyst. This catalyst showed excellent catalytic activity, high selectivity, and recyclability. The polymer-anchored Cu(II) catalyst could be easily recovered by filtration and reused more than five times without appreciable loss of its initial activity.

The O-arylation of phenols with aryl halides, the N-arylation of N—H heterocycles with arylboronic acids, and the amination of primary amines with aryl boronic acids or aryl iodides are efficiently promoted by copper complex (I).

Selective oxidation of olefins has been carried out in water medium with tert-butylhydroperoxide (TBHP, 70% aqueous) as an oxidant using polymer-anchored Ni(II) complex as a catalyst. Several parameters were varied to optimize the reac-tion conditions. Under the optimized reaction conditions olefins gave selectively allylic oxidation products. The present polymer anchored Ni(II) complex can be recycled five times without any appreciable loss in catalytic activity.

The new heterogeneous palladium(II) catalyst can be prepared readily from inexpensive and commercially available starting materials.

The catalyst shows excellent activity for a broad spectrum of aryl halides under phosphine- and copper-free conditions.

The copper(II) Schiff base catalyst is air-stable and can be reused for five times with only minimal loss of activity.