Zero, one, or three? The role of Au0, AuI, and AuIII cations in the heterogeneous gold catalyst Au/CeO2 was investigated with copper-free Sonogashira cross-coupling reaction iodobenzene phenyl acetylene (see picture). Reactions carried out under both homogeneous conditions using distinct species reveal that AuI is active for reaction.

By a combination of kinetic and theoretical studies it is concluded that gold intrinsically active to perform the Sonogashira coupling reaction between phenylacetylene iodobenzene. The presence Pd impurities not mandatory for catalyst activity.

Au(III)−Schiff base complexes are active hydrogenation catalysts, giving turnover frequencies similar to those of the corresponding Pd(II), which has same d8 electronic structure as Au(III). The mechanism reaction been studied in detail by a combination kinetic experiments and theoretical calculations. It is predicted tested that nature solvent plays critical role for heterolytic cleavage H2 (controlling step). Taking this into account, properly selecting solid supports (polarity...

A series of gold complexes were tested as catalysts in the synthesis propargylamines by three component coupling reaction amines, aldehydes, and alkynes. These are efficient for three-component (yields up to 97%). In homogeneous solution, conversions respective propargylamine higher than under heterogeneous conditions. Heterogenized stable recoverable at least six cycles. Ligands, gold(I) or gold(III), heterogenized systems have pronounced effects on catalytic activity corresponding complexes.

Abstract Mononuclear unsymmetrical N‐heterocyclic carbene‐gold complexes and the corresponding solid catalysts in which a gold‐carbene complex has been immobilized on silica gel, ordered mesoporous (MCM‐41), delaminated zeolite (ITQ‐2) have prepared. These new tested hydrogenation of alkenes Suzuki cross‐coupling reaction to afford selectively non‐symmetrical biaryls. reactions were studied with soluble as well heterogenized counterpart catalysts. The high accessibility introduced by...

Here we report the design and synthesis of a new conjugated microporous polymer based on BODIPY dye (CMPBDP) which has shown excellent luminescence properties an efficient heterogeneous photocatalytic activity. CMPBDP shows high thermal stability surface area with size efficiently catalyzes selective oxidation thioanisole into corresponding sulfoxide via singlet oxygen under visible light (up to 500 nm). The rate materials is 4-fold faster that soluble (used as reference) same reaction...

Worth their weight in gold: Au/CeO2 nanoparticles are a highly active catalyst for the hydrosilylation of large variety unsaturated compounds with high chemo- and regioselectivity. To understand nature catalytic sites, AuI AuIII phosphine-free stable organogold complexes supported counterparts were prepared relative activity towards was elucidated. Supporting information this article is available on WWW under http://www.wiley-vch.de/contents/jc_2002/2007/z702032_s.pdf or from author. Please...

We described the use of one porous polymeric aromatic framework (PPAF) with a 9,9′-spiro-bisfluorene unit as support in heterogeneous catalysis. The material was functionalized acid and base active sites used bifunctional catalyst model cascade reaction. This recycled up to eight times only small loss activity.

Rh-complexes with N-based chiral ligands, when anchored on a modified USY-zeolite which contains profuse supermicropores, produce remarkable increase of enantioselectivity (>95%) in the hydrogenation N-acyldehydrophenylalanine derivatives and represent truly heterogeneous counterpart homogeneous organometallic catalysts.

A new neutral dimeric gold(I) complex bearing the 1,2-bis[(2R,5R)-2,5-dimethylphospholanebenzene] [(R,R)-Me-Duphos] ligand has been synthesized which catalyzes asymmetric hydrogenation of alkenes and imines under mild reaction conditions.

The aldol reaction of hydroxyacetone with different aldehydes using immobilized proline on a mesoporous support, assisted by heat and microwaves, has been explored. It was found that heterogenized L-proline MCM-41 catalyzed reactions in both hydrophilic hydrophobic solvents, provided stereoselectivities some cases complementary to the homogeneous catalyst. heterogeneous catalysts could be reused without significant lost stereoselectivity.

A heterogenized (S)-proline on mesoporous support MCM-41 catalyzes the asymmetric aldol reaction in a wide range of solvents. The progress is dependent nature solvent. Reactions proceed more efficiently hydrophilic polar solvents; however, addition small amount water has positive effect rate and stereoselectivity performed hydrophobic toluene. under heterogeneous conditions also been chiral aldehydes, furnishing useful intermediates for synthesis azasugars.

The copper and gold metal-organic frameworks (MOFs) [Cu(3)(BTC)(2)(H(2)O)(3)](n), [Cu(3)(BTC)(2)] (BTC=benzene-1,3,5-tricarboxylate), IRMOF-3-SI-Au are active reusable solid catalysts for the cyclopropanation of alkenes with high chemo- diastereoselectivities. This type material gives better results than previous while working together homogeneous catalysts. These MOFs can help to bridge gap between heterogeneous catalysis.

Abstract A bifunctional metal organic framework catalyst containing palladium and copper(II) benzene‐1,3,5‐tricarboxylate – MOF‐Cu(BTC)‐[Pd] has been prepared. This enables the performance of tandem Sonogashira/click reaction starting from 2‐iodobenzylbromide, sodium azide alkynes to produce 8 H ‐[1,2,3]triazolo[5,1‐ a ]isoindoles with good yields under mild conditions.

Stable well-defined pincer-type N-heterocyclic carbene−ruthenium complexes were developed as an alternative to phosphine complexes. These highly stable phosphine-free found be efficient catalysts for transfer hydrogen reactions: the conversion of primary alcohols esters and reduction carbonyl compounds. We also describe one approach toward immobilization through covalent bonding silica via a pendant alkoxysilane group.

New chiral CNN-pincer-type gold, palladium, and rhodium complexes containing N-heterocyclic carbene substituent (S)-N-tert-butyl-methylpyrrolidine-2-carboxamide as auxiliary have been synthesized studied for asymmetric hydrogenation. The were prepared by the silver transfer route from respective complex. reaction with [RhCl(cod)]2 (cod = cycloocta-1,5-diene), PdCl2(CH3CN)2, or K[AuCl4] affords corresponding cationic [Rh(cod)(ligand)]Cl, [PdCl(ligand)]Cl, [AuCl(ligand)]Cl2 in which ligand...

A photoexcited Zr-based MOF having two different linkers shows excimer formation, energy transfer and ligand-to-cluster charge reactions.

Abstract We present a widely applicable approach for the preparation of Pd‐complexes supported on silica‐based mesoporous and laminar inorganic solids (silica gel, purely siliceous acidic MCM‐41, delaminated zeolites ITQ‐2 ITQ‐6) which involves use Schiff bases 2‐ tert ‐butyl‐4‐methyl‐6{( E )‐[(2 S )‐1‐(1‐arylmethyl)pyrrolidinyl]imino}methylphenol (aryl=phenyl, 1‐naphthyl, 2‐naphthyl) as anchored ligands. As an extension our research in “recyclable catalytic systems” we report results...