Homogeneous and heterogeneous catalytic oxidation of benzylic and secondary alcohols with a metal dioxygenato complex in the presence of 2-methylpropanal and dioxygen

Catalytic activities of heterogeneous catalysts obtained by copolymerization of metal-containing 2-(acetoacetoxy)ethyl methacrylate

Among the synthetic strategies commonly used for supporting a metal complex onto an organic polymer in order to obtain an heterogenous catalyst, a valid choice is to synthesize a metal containing monomer (MCM), which can subsequently be subjected to polymerization with suitable comonomers and crosslinkers, achieving a supported transition metal catalyst as a metal-containing polymer (MCP). In this context, during the last two decades, we explored the use of 2-(acetoacetoxy)ethyl methacrylate (HAAEMA) as a ligand to prepare several MCMs for the relevant MCPs. In this review we summarize and discuss our developments in the studies of the catalytic activity of these “hybrid” catalysts. These catalysts have demonstrated high efficiency and/or excellent selectivity in several kinds of chemical reactions and very often they could be recovered and reused in multiple cycles maintaining their activity and selectivity without suffering from appreciable metal leaching.

Tuneable nature of metal organic frameworks as heterogeneous solid catalysts for alcohol oxidation

This Feature article describes on the recent developments in the use of metal organic frameworks as heterogeneous solid catalysts for the selective alcohol oxidation by either tuning the actives sites around the metal centre, or anchoring them on the ligands or using the pores to embed metal nanoparticles inside.

Application of metal organic frameworks M(bdc)(ted)0.5 (M = Co, Zn, Ni, Cu) in the oxidation of benzyl alcohol

The selective oxidation of benzyl alcohol to benzaldehyde is an important process in heterogeneous catalysis and green organic chemistry.

Cobalt(II) Dioxygen Carriers Based on Simple Diamino Ligands: Kinetic and ab Initio Studies

The kinetics of the oxygenation reaction of CoL2(2+) complexes (L=ethylenediamine (en), N,N'-dimethylethylenediamnine (dmen)) have been investigated in dimethyl sulfoxide (dmso) at 298 K and in a medium adjusted to 0.1 mol dm(-3) with Et4NClO4 by means of a UV-vis spectrophotometric technique. The reaction mechanisms are consistent with the fast formation of superoxo 1:1 initial CoL2-O2 species (L=en, dmen), whereas the dimeric mu-peroxo (CoL2)2O2 adduct is formed only when L=en, in the rate determining step. The kinetic results are discussed taking into account the effects of ligand/solvent substitution. EPR results give information on the electronic structure and the coordination geometry of the Co(II) complexes and further confirm the stoichiometry of the species formed. Ab initio calculations provide insights on the geometrical parameters of all the complexes investigated and allow us to draw some hypotheses about the influence of H.H nonbonded interactions in the eventual formation of the dimeric mu-peroxo (CoL2)2O2 complexes. Solvational effects are also considered. The formation of the (CoL3)2O2 adduct is also proved when L=en by means of O2 volumetric absorption.

Unusual reactivity of molecular oxygen with pi-allylnickel(N-heterocyclic carbene) chloride complexes

One-pot preparation and characterization of the first reported nickel(II) complexes containing a single imidazol-2-ylidene ligand are reported. Subsequent treatment of these complexes with molecular oxygen at room temperature results in rapid formation of a mu-hydroxo dimer and alpha,beta-unsaturated carbonyl compounds. Mechanistic investigations indicate that this reaction proceeds via reversible oxygen binding followed by rate-limiting decomposition of the resulting metal-oxygen species.