James Sanderson

Non-precious-metal-catalyzed reactions are of increasing importance in chemistry due to the outstanding ecological and economic properties of these metals. In the subfield of metal-catalyzed direct C−H functionalization reactions, recent years have shown an increasing number of publications dedicated to this topic. Nickel, cobalt, and last but not least iron, have started to enter a field which was long dominated by precious metals such as palladium, rhodium, ruthenium, and iridium. The present review article summarizes the development of iron-, nickel-, and cobalt-catalyzed C−H functionalization reactions until the end of 2016, and discusses the scope and limitations of these transformations.

Worth their weight: Non-precious-metal- catalyzed direct C−H functionalization reactions are of increasing importance in chemistry due to the outstanding ecological and economic potential. The present Review article summarizes the development of iron, nickel, and cobalt-catalyzed C−H activation reactions and discusses the scope and limitations of these transformations.

Hyperconjugative, steric, and electrostatic effects were evaluated as possible sources of the helicity in linear perfluorinated alkanes through analysis of natural bond orbitals and classical electrostatics. Contrary to previous rationalizations, which indicate dominating steric or electrostatic effects, this analysis indicates that hyperconjugative stabilization through σ_CCσ*_CF interactions are the underlying driving force for the origin of the observed helicity in perfluoroalkanes.

Hype and twist: It is hyperconjugation (i.e. quantum mechanics), not simple electrostatics, that dictates the helical shape of perfluoroalkanes. This conclusion is contrary to previous rationalizations, which indicate dominating steric or electrostatic effects.

Bridging iron hydrides are proposed to form at the active site of MoFe-nitrogenase during catalytic dinitrogen reduction to ammonia and may be key in the binding and activation of N₂ via reductive elimination of H₂. This possibility inspires the investigation of well-defined molecular iron hydrides as precursors for catalytic N₂-to-NH₃ conversion. Herein, we describe the synthesis and characterization of new P₂^P′PhFe(N₂)(H)_x systems that are active for catalytic N₂-to-NH₃ conversion. Most interestingly, we show that the yields of ammonia can be significantly increased if the catalysis is performed in the presence of mercury lamp irradiation. Evidence is provided to suggest that photo-elimination of H₂ is one means by which the enhanced activity may arise.

Light it up: Light-enhanced N₂-to-NH₃ conversion catalysis is reported. New triphos-supported Fe(N₂)H_x catalysts provide higher ammonia yields for 1 atm N₂, and as much as 180 % improvement upon irradiation by a mercury lamp.

The ability of nickel to cleave strong σ-bonds is again in the spotlight after a recent report that demonstrates the feasibility of using nickel complexes to promote decarbonylation of diaryl ketones. This transformation involves the cleavage of two strong C−C(O) bonds and avoids the use of noble metals, hence reinforcing the potential of decarbonylation as a technique for forging C−C bonds.