Communication
Csp2–H/F bond activation and borylation with iron
[{K(18-C-6)}2(tBupyrr2pyr)Fe(N2)] splits the Csp2–H and Csp2–F bond of benzene and fluorobenzene to form [{K(18-C-6)}(tBupyrr2pyr)Fe(C6H5)] and reaction with ClBcat yields [K(18-C-6)(thf)2][(tBupyrr2pyr)FeCl]. Usage of B2pin2 traps the hydride of the arene as [K(18-C-6)HB2Pin2].
Communication
Synthesis of heteroleptic bis-phosphine bis-NHC iron (0) complexes: a strategy to enhance small molecule activation
We report low-valent iron complexes containing bis-NHC and bis-phosphine donor ligands that coordinate and strongly activate N2 and CO.
Low-valent group 6 metals/Al(C6F5)3 donor–acceptor systems for CO2 activation and cleavage
Donor–acceptor systems for CO2 activation combining a formally zero-valent group 6 metal as the donor with the Lewis acid Al(C6F5)3 (AlCF) are reported.
Reduction of CS2 to an ethanetetrathiolate by a hydride-bridged uranium–iridium heterobimetallic complex
We report the synthesis of a heterobimetallic U(III)–Ir species which reacts with CS2 to form the novel ethanetetrathiolate fragment via hydride insertion and C–C coupling.
Communication
Synthesis of a potassium capped terminal cobalt–oxido complex
An unusual example of a potassium capped terminal cobalt–oxido complex has been isolated and crystallographically characterized.
Communication
A neutral crystalline imino-substituted silyl radical
The neutral three-coordinated imino(silyl)silyl radical was isolated from the reaction of ItBuN-SiBr3 with NaSitBu2Me. The radical was fully characterized by SC-XRD and EPR spectroscopy and supported by quantum chemical calculations.
Communication
CO2 cleavage by tantalum/M (M = iridium, osmium) heterobimetallic complexes
A novel Ta/Os complex [Ta(CH2tBu)3(μ-H)3OsCp*], and its iridium analogue [Ta(CH2tBu)3(μ-H)2IrCp*], efficiently cleave CO2 under mild conditions, forming tantalum oxo species and CpIr(CO)H2 or CpOs(CO)H3.
Hydrazido complexes prepared by methylation of an anionic end-on bridging dinitrogen dititanium complex
Stepwise methylation of end-on bridging dinitrogen to a hydrazido ligand to a pentamethylhydrazinium salt is mediated by a titanium complex.
Communication
Efficient carbene transfer reactivity mediated by Fe(II) complexes supported by bulky alkoxides
The reaction of Fe(OR)2(THF)2 (OR = bulky alkoxide ligand) with PhIC(CO2Me)2 results in the formation of reactive remote carbene/vinyl radical intermediate that undergoes facile cyclopropanation or dimerization.
Dinitrogen activation at chromium by photochemically induced CrII–C bond homolysis
Exposure of (POCOPtBu)Cr(Bn) to 427 nm blue light under 1 atm N2 promoted Cr–CBn bond homolysis and led to N2 activation forming [(POCOPtBu)Cr]2(μ-N2).
Ni2P active site ensembles tune electrocatalytic nitrate reduction selectivity
Intrinsic active site ensembles on Ni2P nanocrystal surfaces direct the selective reduction of nitrate to ammonia through the potential-dependent co-adsorption of H* and NOx*.
Communication
Appropriation of group II metals: synthesis and characterisation of the first alkaline earth metal supported transition metal carbonite complexes
Complexes where magnesium and calcium ions assist CO2 activation at nickel centres have been accessed and were found to enter into Schlenk-type equilibria.
A vertically-stacked MXene/rGO composite membrane for highly efficient H2/CO2 separation
In comparison to the horizontally stacked membrane, the bioinspired vertical channels offered more direct and less convoluted paths, resulting in an order of magnitude increase in hydrogen permeability.
Catalytic dinitrogen reduction to hydrazine and ammonia using Cr(N2)2(diphosphine)2 complexes
Cr(N2)2(diphosphine)2 complexes catalyze the reduction of dinitrogen at room temperature using SmI2 and ethylene glycol or H2O to form hydrazine and ammonia.
Communication
Temperature induced single-crystal to single-crystal transformation of uranium azide complexes
A temperature-induced single-crystal to single-crystal transformation was observed in monoanionic N–P ligand-supported uranium azide complexes.
Communication
Post transition metal substituted Keggin-type POMs as thin film chemiresistive sensors for H2O and CO2 detection
Chemiresitive sensing allows the affordable and facile detection of small molecules such as H2O and CO2.
Steric control of Mg–Mg bond formation vs. N2 activation in the reduction of bulky magnesium diamide complexes
Reduction of a bulky diamido-magnesium(II) complex has yielded the potassium salt of a dimagnesium(I) dianion, whereas prior reduction of a bulkier analogue gave an activated N2 complex. The relevance of ligand bulk in these processes is discussed.
Paper
Bio-inspired copper complexes with Cu2S cores: (solvent) effects on oxygen reduction reactions
A new mixed-valent Cu complex (6) allows for the systematic study of oxygen reduction reactions in acetonitrile/acetone and comparison with its parent (1). Kinetics and selectivity are influenced, suggesting changes at the chemical structure of (6).
Reactivity of low-valent nickel carbonyl species supported by acridane based PNP ligands towards iodoalkanes
Selective C–C coupling occurs at the sterically well-protected nickel(0 or I)–CO site.
About this collection
Reactions of small molecules (e.g., N2, H2, CO, CO2, O2, NH3, etc.) are fundamental to societal challenges associated with energy and the environment. Removal of certain small molecules from the atmosphere is key to environmental remediation, while development of catalytic redox processes of small molecules is central to renewable energy generation and storage. Valorisation of small molecules can also improve efficiency and sustainability of industrial processes. Through all these research directions, understanding the mechanisms for small molecule activation provides insight into fundamental principles of chemical reactivity.
Guest edited by Professor Neal Mankad (University of Illinois Chicago, USA) and Professor Marinella Mazzanti (EPFL, Switzerland), this joint ChemComm and Dalton Transactions collection covers research on stoichiometric and catalytic transformations of small molecules of relevance to energy and the environment, emphasising the application of molecular compounds but also including solid state materials in small molecule transformations.