1. Advantages of Chemical Redox Agents 878 2. Disadvantages of Chemical Redox Agents 879 C. Potentials in Nonaqueous Solvents 879 D. Reversible vs Irreversible ET Reagents 879 E. Categorization of Reagent Strength 881 II. Oxidants 881 A. Inorganic 881 1. Metal and Metal Complex Oxidants 881 2. Main Group Oxidants 887 B. Organic 891 1. Radical Cations 891 2. Carbocations 893 3. Cyanocarbons and Related Electron-Rich Compounds 894

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Chemical Redox Agents for Organometallic Chemistry

Interest in catalysis by metal nanoparticles (NPs) is increasing dramatically, as reflected by the large number of publications in the last five years. This field, "semi-heterogeneous catalysis", is at the frontier between homogeneous and heterogeneous catalysis, and progress has been made in the efficiency and selectivity of reactions and recovery and recyclability of the catalytic materials. Usually NP catalysts are prepared from a metal salt, a reducing agent, and a stabilizer and are supported on an oxide, charcoal, or a zeolite. Besides the polymers and oxides that used to be employed as standard, innovative stabilizers, media, and supports have appeared, such as dendrimers, specific ligands, ionic liquids, surfactants, membranes, carbon nanotubes, and a variety of oxides. Ligand-free procedures have provided remarkable results with extremely low metal loading. The Review presents the recent developments and the use of NP catalysis in organic synthesis, for example, in hydrogenation and C--C coupling reactions, and the heterogeneous oxidation of CO on gold NPs.

Nanoparticles as Recyclable Catalysts: The Frontier between Homogeneous and Heterogeneous Catalysis

Metal species with different size (single atoms, nanoclusters, and nanoparticles) show different catalytic behavior for various heterogeneous catalytic reactions. It has been shown in the literature that many factors including the particle size, shape, chemical composition, metal–support interaction, and metal–reactant/solvent interaction can have significant influences on the catalytic properties of metal catalysts. The recent developments of well-controlled synthesis methodologies and advanced characterization tools allow one to correlate the relationships at the molecular level. In this Review, the electronic and geometric structures of single atoms, nanoclusters, and nanoparticles will be discussed. Furthermore, we will summarize the catalytic applications of single atoms, nanoclusters, and nanoparticles for different types of reactions, including CO oxidation, selective oxidation, selective hydrogenation, organic reactions, electrocatalytic, and photocatalytic reactions. We will compare the results o...

Metal Catalysts for Heterogeneous Catalysis: From Single Atoms to Nanoclusters and Nanoparticles.

Efficient and reliable amplification of chirality has borne its greatest fruit with transition metal-catalyzed reactions since enantiocontrol may often be imposed by replacing an achiral or chiral racemic ligand with one that is chiral and scalemic While the most thoroughly developed enantioselective transition metal-catalyzed reactions are those involving transfer of oxygen (epoxidation and dihydroxylation)1,2 and molecular hydrogen,3 the focus of this review is on the area of enantioselective transition metal-catalyzed allylic alkylations which may involve C-C as well as C-X (X ) H or heteroatom) bond formation4-9 The synthetic utility of transitionmetal-catalyzed allylic alkylations has been soundly demonstrated since its introduction nearly three decades ago10-21 In contrast to processes where the allyl moiety acts as the nucleophilic partner, we will limit our discussion to processes which result in nucleophilic displacements on allylic substrates (eq 1) Such reactions have been recorded with a broad

http://web4.uwindsor.ca/users/j/jlichaa/reference.nsf/0/10ff8b04ff3a317885256d88005720f6/$FILE/cr-1996-96-395-allylpd-asym.pdf

Asymmetric Transition Metal-Catalyzed Allylic Alkylations.

This critical review presents a comprehensive study of transition-metal carboxylate clusters which may serve as secondary building units (SBUs) towards construction and synthesis of metal–organic frameworks (MOFs). We describe the geometries of 131 SBUs, their connectivity and composition. This contribution presents a comprehensive list of the wide variety of transition-metal carboxylate clusters which may serve as secondary building units (SBUs) in the construction and synthesis of metal–organic frameworks. The SBUs discussed here were obtained from a search of molecules and extended structures archived in the Cambridge Structure Database (CSD, version 5.28, January 2007) which included only crystals containing metal carboxylate linkages (241 references).

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Secondary building units, nets and bonding in the chemistry of metal–organic frameworks

Studies of Ligand Additions to Coordinatively Unsaturated Dirhenium Complexes Containing the Bulky PBut3 Ligand

Transmetalation Reactions Yield New Tetra- and Pentairidium Carbonyl Complexes Containing σ-Bonded Phenyl Rings

The effect of a vinyl substituent on the ring opening of a substituted tetrahydrothiophene at a triosmium center

In recent studies, we have shown that Re{sub 2}(CO){sub 9}(NCMe)(1) can serve as a catalyst for the macrocyclization of thietanes. We have now found that 1 also activates {beta}@-propiothiolactone, SCH{sub 2} CH{sub 2}C=O(2), toward opening of the heterocyclic ring under mild conditions. The known polymer (SCH{sub 2}CH{sub 2}C=O){sub n}{sup 2} (55% yield) and a mixture of new cyclooligomers (SCH{sub 2}-CH{sub 2}C=O){sub n}, two of which,1,5,9,13-tetrathiacyclohexadecane-2,6,10,14-tetrone (3) (22% isolated yield) and 1,5,9,13,17, 21-hexathiacyclotetracosane-2,6,10,14,18,22-hexone (4), n = 6(2% isolated yield), have been isolated and characterized crystallographically. Recent studies have provided some of the first examples of polythiolactones from acyclic precursors. These molecules all exhibit head-to-head/tail-to-tail orientations of the thiolactone groupings(A). Compounds 3 and 4 are the first members of a new family of head-to-tail oriented polythiolactones B that have a clear and demonstrated potential to exhibit new supramolecular properties. 8 refs., 2 figs.

Richard D. Adams

Papers

Studies of Ligand Additions to Coordinatively Unsaturated Dirhenium Complexes Containing the Bulky PBut3 Ligand

Transmetalation Reactions Yield New Tetra- and Pentairidium Carbonyl Complexes Containing σ-Bonded Phenyl Rings

The effect of a vinyl substituent on the ring opening of a substituted tetrahydrothiophene at a triosmium center

Catalytic Cyclo-oligomerization of β-Propiothiolactone by a Dirhenium Complex. A Convenient Route to New Polythiolactone Macrocycles

The partial hydrogenation of small unsaturated molecules by osmium cluster compounds. The reaction of diispropylcarbodiimide with H2Os3(CO)10