A Convenient and Stable Heterogeneous Nickel Catalyst for Hydrodehalogenation of Aryl Halides Using Molecular Hydrogen.

Invited for this month's cover is the group of Matthias Beller at the Leibniz Institute for Catalysis in Rostock in collaboration with Muhammad Anwar and Sarim Dastgir at the Qatar Environment and Energy Research Institute in Doha. The image illustrates a hydrodehalogenation of polybrominated diphenyl ether (PBDE) using a heterogeneous nickel catalyst supported on titanium oxide and dihydrogen. The Research Article itself is available at 10.

A Convenient and Stable Heterogeneous Nickel Catalyst for Hydrodehalogenation of Aryl Halides Using Molecular Hydrogen.

Hydrodehalogenation is an effective strategy for transforming persistent and potentially toxic organohalides into their more benign congeners. Common methods utilize Pd/C or Raney-nickel as catalysts, which are either expensive or have safety concerns. In this study, a nickel-based catalyst supported on titania (Ni-phen@TiO -800) is used as a safe alternative to pyrophoric Raney-nickel.

Aldehydes and ketones influence reactivity and selectivity in nickel-catalysed Suzuki-Miyaura reactions.

The energetically-favorable coordination of aldehydes and ketones - but not esters or amides - to Ni during Suzuki-Miyaura reactions can lead either to exquisite selectivity and enhanced reactivity, or to inhibition of the reaction. Aryl halides where the C-X bond is connected to the same π-system as an aldehyde or ketone undergo unexpectedly rapid oxidative addition to [Ni(COD)(dppf)] (), and are selectively cross-coupled during competition reactions. When aldehydes and ketones are present in the form of exogenous additives, the cross-coupling reaction is inhibited to an extent that depends on the strength of the coordination of the pendant carbonyl group to Ni.

Practical Catalytic Cleavage of C(sp )-C(sp ) Bonds in Amines.

The selective cleavage of thermodynamically stable C(sp )-C(sp ) single bonds is rare compared to their ubiquitous formation. Herein, we describe a general methodology for such transformations using homogeneous copper-based catalysts in the presence of air. The utility of this novel methodology is demonstrated for C -C bond scission in >70 amines with excellent functional group tolerance.

Path analysis of subsistence farmers' use of veterinary services in Zimbabwe.

We used factor and path analyses to identify the causal paths or relationships between variables affecting the demand and use by subsistence farmers of the various services offered by government-employed veterinary livestock technicians (VLTs) in Zimbabwe in 1996. We examined whether the farmer had implemented the VLT-recommended livestock-management procedures. Various factors that have been reported or theorized as important in the demand for veterinary services by subsistence farmers are described.