Recent developments in the chemistry of η3-allylruthenium(IV) complexes are due to their straightforward synthesis resulting from oxidative addition of allylic substrates to a ruthenium(II) center. Subsequent reaction with a nucleophile is the basis of their involvement in the catalytic allylic substitution reaction. We focus here on ruthenium-catalyzed substitution of allylic substrates by C-,...

Traditional nanostructured design of cerium oxide catalysts typically focuses on their shape, size, and elemental composition. We report a different approach to enhance the catalytic activity of cerium oxide nanostructures through engineering high density of oxygen vacancy defects in these catalysts without dopants. The defect engineering was accomplished by a low pressure thermal activation pr...

The acylation of alcohols catalyzed by N,N-dimethylamino pyridine (DMAP) is, despite its widespread use, sometimes confronted with substrate-specific problems: For example, target compounds with multiple hydroxy groups may show insufficient selectivity for one hydroxyl, and the resulting product mixtures are hardly separable. Here we describe a concept that aims at tailor-made catalysts for the...

Palladium (Pd)-catalyzed selective hydrogenation of alkynes has been one of the most studied hydrogenation reactions in the last century. However, kinetic studies conducted to reveal the catalyst's active centers have been hindered because of dynamic surface changes on Pd during the reaction. In the present study, bimetallic Pd-Au nanoparticles supported on carbon nanotubes have been synthesize...

Inspired by the principle of DNA base-pairing, a new concept for the self-assembly of molecular catalysts is described herein. Thus, employing A–T analogous complementary hydrogen-bonding templates, self-assembly of monodentate to bidentate ligands in the coordination sphere of a transition-metal salt occurs to give defined self-assembly catalysts. This approach is intrinsically combinatorial a...

In spite of the inherent advantages of reuse and stability of immobilized chiral catalysts, they are frequently not enough to justify the effort necessary to immobilize the chiral complexes, unless additional advantages are found. When chiral catalysts are immobilized on solids with surface and pores of well controlled size, shape and dimensionality, the solid may act as a nano-reactor reducing...

The Z-selective ethenolysis activity of chelated ruthenium metathesis catalysts was investigated with experiment and theory. A five-membered chelated catalyst that was successfully employed in Z-selective cross metathesis reactions has now been found to be highly active for Z-selective ethenolysis at low ethylene pressures, while tolerating a wide variety of functional groups. This phenomenon a...

More environmentally benign alternatives to current chemical processes, especially large-scale, fundamental reactions such as ester condensations, are highly desirable for many reactions. Bulky diarylammonium pentafluorobenzenesulfonates and tosylates serve as extremely active dehydration catalysts for the ester condensation reaction of carboxylic acids with equimolar amounts of sterically dema...

in this research, the selective oxidation of benzene to maleic anhydride (man) in a fixed-bed reactor was studied. the gas phase catalytic oxidation of benzene was carried outin a laboratory scale fixed bed reactor on the catalysts, which were prepared having two different compositions on silica gel. the effects of temperature, flow rates of benzene and air, and catalyst type on the reaction se...

The use of heterogenization as a method for achieving clean synthesis is discussed. The chemical modification of mesoporous solids can be used to make a range of catalysts, including solid acids and bases, and stable metal complexes for selective oxidations and other reactions. By avoiding an aqueous quench stage in the separation, the heterogenization of catalysts and reagents can lead to subs...