Noyori-type catalysts feature a metal-bound N–H moiety but can operate without dissociation of this bond. This knowledge is consistent with the activity of catalysts bearing tertiary amines and will help in the design of better catalysts for (de)hydrogenations, transfer (de)hydrogenations and related conversions. See Dub and Gordon

Chemical looping processes can be mediated by redox-active metal oxides. This cover image depicts a doped metal oxide surface at which conversions of substrates such as methane, water, carbon dioxide and carbon monoxide can occur. See Gong et al

Gene delivery vehicles capture and protect nucleic acid cargoes, deliver them to cells and tissues, and are important for biological research as well as the treatment of diseases such as cancer. Chemistry has a key role in developing innovative synthetic materials for next-generation gene therapies to safely and efficaciously deliver nucleic acids to target sites in vivo. See Montenegro et al. Montenegro

Click chemistry allows us to label small molecules with fluorophores, and is amenable for the imaging of almost any biologically active compound within cells. This cover image features micrographs of cancer cell nuclei stained with fluorophores by means of click chemistry. Data like these can teach us about the mechanisms of action of small molecules in biological settings.

Automation is now routinely applied at individual stages of the drug discovery cycle. More recent efforts have focused on integrating adjacent stages with long-term goal of realising the fully autonomous discovery of biologically-active small molecules. See Nelson et al.

Metal–ligand interactions are widely exploited for the design of new drugs. An atomistic understanding of metal-mediated interactions, provided by powerful computational approaches, will aid the design of both potent metalloenzyme inhibitors and metal-containing drugs. See De Vivo, M. et al.

Ongoing developments in our ability to produce shorter and shorter X-ray pulses are enabling nuclear and electronic dynamics to be tracked with temporal resolution in the femtosecond–attosecond range. The image shows a transient absorption spectrum that allows the ring-opening of photoexcited cyclohexadiene to be followed in exquisite detail. See: Kraus, P. M. et al.

Incorporating polar co-monomers into otherwise unfunctionalized polyolefins affords materials with distinct properties but poses a challenge for archetypal metal catalysts, which are typically poisoned on binding to heteroatom lone pairs. This cover image depicts one strategy to overcome this challenge, whereby one metal centre sequesters a polar group, with an adjacent metal centre then being able to insert the olefin into a growing polymer chain.

See: Chen, C. Designing catalysts for olefin polymerization and copolymerization: beyond electronic and steric tuning. Nat. Rev. Chem. (2018).

Discovery and design of new therapeutics require understanding of processes across different spatiotemporal scales. The development of multiscale simulation techniques enables us to simultaneously study drug mechanism of action at both atomic and cellular level. The cover image is a representative example of a quantum mechanics–molecular mechanics (QM/MM) model of an enzyme–drug complex (data from J. Am. Chem. Soc., 2013, 135 (21), pp 8001–8015).

Our ability to rationalize and predict the optical properties of simple molecules or complex systems relies on the use of approximations of the sophisticated theories describing light–matter interactions. Common approximations can hide fundamental aspects of light–matter interactions, but theoretical advances can help us to reveal them.

See: Ruggenthaler, M., Tancogne-Dejean, N., Flick, J., Appel, H. and Rubio, A. From a quantum-electrodynamical light–matter description to novel spectroscopies. Nat. Rev. Chem. 2, 0118 (2018).

Species containing planar pentacoordinate carbon centres have, to many eyes, strikingly exotic and inconceivable structures. Yet, many such species have been predicted using computational chemistry, and we now have principles that can be applied to designing (and eventually isolating) these interesting motifs.

See: Vassilev-Galindo, V., Pan, S., Donald, K. J. & Merino, G. Planar pentacoordinate carbons. Nat. Rev. Chem. 2, 0114 (2018).

Phytocannabinoids are plant-derived ligands for the cannabinoid receptors. The chemical synthesis of phytocannabinoids and their metabolites will help in the study of scarce or unstable compounds, and potentially provide access to abiological derivatives that may have uses in medicine.

See: Reekie, T. A., Scott, M. P. & Kassiou, M. The evolving science of phytocannabinoids. Nat. Rev. Chem. 2, 0101 (2018).