Mechanistic studies in catalysis

Part of the mission statement of Catalysis Science & Technology (CST) offers a “balanced mix of applied fundamental experimental and computational research”. Elsewhere the stated aim is to provide an inclusive penumbra for all areas of catalysis – given the sheer size and reach of the subject this is a highly challenging objective. There may have been tendencies in the past for different sub-disciplines of catalysis to be insulated from one another and it is encouraging to see artificial barriers gradually breaking down. A journal that all the sub-disciplines of catalysis can share comfortably will only help to accelerate the process; a quick glance down the title list of any recent issue of CST will reinforce that conclusion. It is the scientific community rather than the publisher that decides the fate of a new journal and for CST a portfolio of well over 3000 pages in 2013 – only the third year of publication – provides a very positive statement.

Understanding how catalytic reactions work is an inseparable component of the science, and a necessary adjunct to progress. Techniques used in one area help cross-fertilize others. We are pleased to present a set of papers that reflect the aims and intentions of the journal, and warmly thank the individual authors for their contributions. There are two perspective articles; Morris and Sonnenberg (10.1039/c4cy00468j) call on their experience in iron-complex catalysis to evaluate the ways that homogeneous and heterogeneous catalysis (e.g. by nanoparticles) can be distinguished experimentally, and Schmidt and his colleagues (10.1039/c4cy00479e) consider selectivity in competitive catalytic reactions, showing that their analyses complement rate studies. Heller and co-workers (10.1039/c4cy00497c) focus on the precatalysts involved in rhodium asymmetric hydrogenation and the effects that operate during catalytic turnover in their mini-review. The Fischer–Tropsch reaction is topical, and De Chen, Holmen and co-workers (10.1039/c4cy00566j) combine DFT and experimental studies to elucidate the less desirable pathways leading to methane; Hensen and co-workers (10.1039/c4cy00709c) study reactions in aqueous media with Ru nanoparticles as catalyst, concentrating on the balance between hydrocarbons and oxygen-containing products. In detailed studies of heterogeneous catalytic oxidation, Fouladvand and co-workers (10.1039/c4cy00486h) utilise diffuse reflectance FT IR to monitor the evolution of surface species on Pt in methane oxidation; Muhler's group (10.1039/c4cy00493k) use MS to study the oxidation of ethanal on Au/TiO₂ and find a gold-free pathway at high temperatures. Organocatalysis is represented by Blackmond and Ji (10.1039/c4cy00648h), through their study of the enantioselective urea-catalyzed addition of disubstituted aldehyde enolates to nitroalkenes where there is the potential for reversibility, and thus lowered ee. Nguyen and co-workers (10.1039/c4cy00480a) demonstrate complexation of CO₂ to guanidines when the latter are used to catalyze cycloaddition to amino-alkynes. Pidko's group (10.1039/c4cy00568f) finds a very effective pincer-Ru catalyst for CO₂ hydrogenation, and they demonstrate the importance of an RuH₂ intermediate. Fairlamb and co-workers (10.1039/c4cy00617h) have studied Au-complex catalysed enyne cyclizations with a view to defining the oxidation state of Au during turnover. McIndoe, Weller and their respective groups (10.1039/c4cy00597j) have used direct ES-MS interrogation of reacting systems to probe the Rh(Xantphos)-catalysed hydroboration of neohexene by amine-boranes. Finally, a novel use of catalysis is reported by Duckett et al. (10.1039/c4cy00464g). Their SABRE method uses the reversible co-complexation of para-H₂ and ligands to Ir, such that the free ligand in equilibrium has a very significantly enhanced ¹H NMR.

Overall the contributions nicely reflect the wide spectrum of current mechanistic problems in homogeneous and heterogeneous catalysis and the diverse methods applied to solve them.

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