Electrocatalytic proton reduction by an air-stable nickel(ii)-thiolato PNN pincer complex.

We report an air-stable nickel(ii)-thiolato PNN pincer complex [(PNN)NiII(SC6H4Me)]+[MeC6H4SO3]- (PNN = 2-((di-tert-butylphosphinomethyl-6-diethylaminomethyl)pyridine)) which is capable of reducing protons at an overpotential of 0.54 V at low acid concentrations. The proton reduction can be catalysed using weak or strong acids such as acetic acid and trifluoroacetic acid respectively. In contrast, the chloro and nitrate derivatives of the nickel pincer complex behave as poorer catalysts. A mechanism accounting for the role of the ligand in proton reduction is also briefly outlined.

Facile synthesis of single crystalline rhenium (VI) trioxide nanocubes with high catalytic efficiency for photodegradation of methyl orange.

Single-crystalline rhenium trioxide (ReO3) nanocubes have been prepared for the first time without the need of surfactants via controlled reduction of rhenium (VII) oxide (Re2O7), sandwiched between silicon wafers at 250°C. The metallic ReO3 nanocubes are magnetic and possess surface plasmon resonance (SPR) bands down to the NIR region. The nanocubes also show very high catalytic activity toward the photodegradation of methyl orange (MO) under ambient conditions. A mechanism has been proposed to account for the photodegradation process.

Preparation of rhenium nanoparticles via pulsed-laser decomposition and catalytic studies.

Rhenium (Re) nanoparticles have been synthesized by pulsed-laser decomposition of ammonium perrhenate (NH(4)ReO(4)) or dirhenium decacarbonyl (Re(2)(CO)(10)) in the presence of 3-mercaptopropionic acid (MPA) as capping agent, in both aqueous and organic media. Preliminary studies showed that the MPA-capped Re nanoparticles are capable of catalyzing the isomerization of 10-undecen-1-ol to internal alkenols via long chain migration of the C=C double bond at ca. 200°C. A one-pot synthesis of graphite-coated Re nanoparticles has also been achieved by pulsed-laser decomposition of Re(2)(CO)(10), due to photo-induced catalytic graphitization of the phenyl groups of PPh(3) on the surface of rhenium nanoparticles.

Catalytic rate enhancement observed for alkyne hydrocarboxylation using ruthenium carbonyl-capped nanostructures.

Surface functionalization of Ag nanocubes and nanoparticles with catalytically active ruthenium carbonyl oligomers has been carried out successfully. These functionalized nanostructures catalyze hydrocarboxylation onto terminal alkynes at significantly enhanced rates (33 times) compare to those observed for free ruthenium oligomers. The rate enhancement is facilitated by adsorption of substrates on the surface of the nanoparticles, thus bringing them into close proximity with the catalyst. The size and shape of the Ag nanostructures were retained, indicating that the metallic cores act mainly as a docking site.