Interest in the inelastic collisions of OH radicals stems from their importance in combustion and atmospheric chemistry, but measuring their velocities in specific internal quantum states has proved difficult. Now, David H. Parker and co-workers have demonstrated how velocity-map imaging can be applied to the study of the inelastic scattering of OH using crossedmolecular-beam methods. The cover image shows contour plots of normalized differential crosssections versus velocity for OH collisions with Ar obtained from close-coupling calculations.Article p985IMAGE: SARANDIS MARINAKISCOVER DESIGN: ALEX WING

Metal-organic frameworks (MOFs) are widely investigated for their potential to selectively separate and store environmentally harmful gases. The cover image of this issue shows the structure of a MOF — described by Martin Schröder and co-workers — whose promising capture capabilities rely on hydroxyl groups rather than the traditionally used amine ones. The hydrogen bonding interactions between the host framework and CO2 and SO2 gases were directly visualized by in situ static and dynamic characterization methods, and the results supported by modelling studies.Article p887IMAGE: SIHAI YANGCOVER DESIGN: ALEX WING

A team of researchers led by Trevor Douglas have demonstrated that atom-transfer radical polymerization can be initiated from specific sites on the inside surface of a protein cage to produce a confined crosslinked polymethacrylate derivative (shown schematically on the cover). The pendant amine groups present in the polymer can be reacted with small molecules — such as fluorescent dyes or Gd-based contrast agents for magnetic resonance imaging — to produce hybrid protein–polymer conjugates with a high density of functional labels.

Article p781; News & Views p775

IMAGE: NIKKI SIMON

COVER DESIGN: ALEX WING

Current antiretroviral therapy (ART) can transform HIV infection from a terminal illness to a manageable chronic disease, but hidden HIV can re-ignite infection if treatment is stopped. Jerome Zack, Paul Wender and co-workers have now shown that a series of simplified — and thus synthetically accessible — analogues of the marine natural product bryostatin (one of which is shown on the cover) are able to activate latent HIV in vitro. It is hoped that this approach, in combination with ART, might ultimately lead to eradication of the infection.Article p705;News & Views p692IMAGE: BRIAN LOYCOVER DESIGN: ALEX WING

Photosensitive metal complexes that are able to bind to DNA duplexes (an example of which is depicted on the cover) hold promise for diagnostic and therapeutic applications — but the precise details of how they interact with DNA need to be better understood. A collection of articles in this issue highlight some of the latest advances in elucidating their binding modes as well as challenges associated with this area of research.

Editorial p587; Interview p591; News & Views p594; Article p615; Article p621;

IMAGE: CHRISTINE CARDIN AND JAMES HALL

COVER DESIGN: ALEX WING

Peter Crowley and co-workers have revealed how a sulfonated calixarene interacts with the outer surface of the cytochrome c protein. A combination of NMR spectroscopy and single-crystal X-ray crystallography shows that the calixarene 'explores' the surface of the protein through dynamic binding at multiple sites (depicted on the cover). Gaining understanding of these interactions may aid the crystallization of proteins and the design of ligands for protein recognition.Article p527News & Views p519IMAGE: PETER CROWLEYCOVER DESIGN: ALEX WING

A team of researchers from the University of Windsor in Canada have made a metal–organic framework (shown schematically on the cover) from [2]rotaxane linkers connected together with nodes comprising binuclear Cu(ii) clusters. Heating the material under vacuum at 150 °C removes water molecules from the structure and creates void spaces that enable the crown ether rings of the rotaxane building blocks to rotate unimpeded. This work demonstrates how the dynamics associated with interlocked molecules can be integrated into a robust and ordered framework.

Article p456.

COVER DESIGN: ALEX WING

There is growing interest in using 3D printing across a range of different industries, and Leroy Cronin and co-workers have now applied this technique to produce custom 'reactionware' for chemical reactions and analysis (shown conceptually on the cover). This approach enables active elements — such as catalysts — to be incorporated into the walls of printed vessels and also offers the opportunity to integrate components that facilitate the in situ analysis of a particular reaction.Article p349News & Views p338IMAGE: PHILIP KITSONCOVER DESIGN: ALEX WING

A team of researchers from Radboud University Nijmegen in The Netherlands have assembled a supramolecular system that is capable of self-propulsion. Platinum nanoparticles engulfed into bowl-shaped polymer vesicles — called stomatocytes — catalyse the decomposition of hydrogen peroxide, which serves as a fuel. The cover shows the colour-coded intensity profile of the opening of a stomatocyte, through which the water and oxygen formed in the decomposition process escape, thereby propelling the assembly.Article p268News & Views p247IMAGE: DANIELA WILSONCOVER DESIGN: ALEX WING

The cover image shows the gold electrode used by Rodriguez, Kwon and Koper in their study of gold-catalysed alcohol oxidation. The electrode is in the 'hanging-meniscus configuration' and is immersed in an aqueous solution. When modified with carbon monoxide, the gold surface catalyses the oxidation of certain alcohols in alkaline media. Remarkably, the carbon monoxide acts as a reaction promoter, in contrast to its usual role as a poison.Article p177IMAGE: MARC DE HAAN, PARAMACONI RODRIGUEZ, MARC KOPERCOVER DESIGN: ALEX WING

Randall Snurr and co-workers describe a computational approach for simulating every possible metal-organic framework (MOF) that can be built from a given set of building blocks (metal clusters and organic ligands) — represented conceptually on the cover using Tinkertoys. Some of the properties of MOFs can also be simulated to uncover structure–property relationships or materials suitable for specific applications. The MOF shown on the cover was identified for its methane storage capacity — a property that was subsequently confirmed experimentally.Article p83IMAGE: CHRISTOPHER E. WILMERCOVER DESIGN: ALEX WING

The cover image features the interlaced 'rho' character from Matthew 1:18 in the Lindisfarne Gospels as a backdrop for the X-ray crystal structure of the most complex non-DNA molecular knot synthesized so far. A team led by David Leigh prepared the 160-atom-long pentafoil knot in a one-step reaction from ten organic building blocks and five iron(II) cations. They use a single chloride anion as a template, which, in the solid-state structure, is located at the centre of the pentafoil knot and exhibits ten CH...Cl– hydrogen bonds.Article p15News & Views p7IMAGE: JIM CALLAGHAN (EVOLUTION DESIGN) BASED ON AN IMAGE ©THE BRITISH LIBRARY BOARD. (COTTON NERO D. IV, F.29)COVER DESIGN: ALEX WING