Preparation of cycloaliphatic epoxy hybrids with non-conventional amine-curing agents

Cycloaliphatic epoxy resin has been successfully thermally cured using a polyamino siloxane oligomer as hardener. The curing reaction was followed by infrared spectroscopy in the near range, and thermal transitions were measured by dynamic mechanical thermal analysis. The use of accelerants and a plasticizer (dodecylphenol), and different curing schedules were explored. Cured materials showed high Tg values (around 125–164 °C), and the analysis of laser scanning confocal microscopy images showed that they are homogeneous in the microscale.     

Generation of benzofuroxans by photolysis of crystalline o-nitrophenylazides. A green chemistry reaction

Several benzofuroxans were obtained by photolysis of crystalline o-nitrophenylazides at ambient temperature. In this particular case, the solid matrix favored the elimination of nitrogen and exclusive formation of heterocyclic benzofuroxan. However, this reaction gives quantitative yields only with crystalline o-nitrophenylazides with a high melting point (above 50 °C).     

Unified majorizing sequences for Traub-type multipoint iterative procedures

We present a unified approach to generating majorizing sequences for multipoint iterative procedures in order to solve nonlinear equations in a Banach space setting. The semilocal convergence results have the following advantages over earlier work (under the same computational cost): weaker sufficient convergence conditions, more precise error bounds on the distances involved and more precise information on the location of the solution. Special cases and numerical examples are also provided in this study.     

Multifunctional,Defect‐Engineered Metal–Organic Frameworks with Ruthenium Centers: Sorption and Catalytic Properties

A mixed‐linker solid‐solution approach was employed to modify the metal sites and introduce structural defects into the mixed‐valence Ru^II/III structural analogue of the well‐known MOF family [M₃^II,II(btc)₂] (M=Cu, Mo, Cr, Ni, Zn; btc=benzene‐1,3,5‐tricarboxylate), with partly missing carboxylate ligators at the Ru₂ paddle‐wheels. Incorporation of pyridine‐3,5‐dicarboxylate (pydc), which is the same size as btc but carries lower charge, as a second, defective linker has led to the mixed‐linker isoreticular derivatives of Ru‐MOF, which display characteristics unlike those of the defect‐free framework. Along with the creation of additional coordinatively unsaturated sites, the incorporation of pydc induces the partial reduction of ruthenium. Accordingly, the modified Ru sites are responsible for the activity of the “defective” variants in the dissociative chemisorption of CO₂, the enhanced performance in CO sorption, the formation of hydride species, and the catalytic hydrogenation of olefins.     

Novel Applications of Raney Nickel/Isopropanol: Efficient System for the Reduction of Organic Compounds

Catalytic hydrogenation of various organic substrates with Raney nickel in isopropanol proceeds under mild conditions of temperature and pressure. Comparison with other catalysts systems evidenced the superiority of Raney nickel/isopropanol.     

Regioselective Synthesis of 2-Functionalized Thiophenes by Condensation of α-Mercapto Compounds with β-Aminoenone Derivatives

2-Acylthiophenes and ethyl 2-thiophene-carboxylates are prepared regioselectively by reaction of 3-ctil oroenones and 2-acylenammoni urn chlorides with α-mercapto derivatives in good to moderate yields.     

Model Studies for the Synthesis of Erigerol Synthesis of 1-Deoxy-13-Epierigerol from Grindelic Acid

The stereoselective transformation of grindelic acid, through the known methyl 6α-hydroxygrindelate, into 1-deoxy-13-epierigerol is described.