Graphical Abstract: ChemistryOpen 6/2015

The cover pictureshows hydrogen bonds in the adenine–thymine (AT) Watson– Crick base pair.Ane ssential part of these H-bonds is their covalent component that arises from donor–acceptor interactions between the No rOlone pairs and the N–H antibonding s*a cceptor orbital. This charge-transfer interaction is represented by the green figures walking over the pedestrian crossing, connecting the two bases. We reveal that this covalentcomponent is the reason why H-bonds between DNA bases and/orunsaturated model bases are significantly stronger than those between analogous saturated bases. This contrasts sharply with the classical picture of predominantly electrostatic H-bonds which is not only incomplete in terms of ap roper bonding mechanism, but also fails to explain the trend in stability.F or more details, see the Full Paper on p. 318 ff. 198 The Role of Aromaticity,Hybridization, Electrostatics, and Covalency in Resonance-Assisted Hydrogen Bonds of Adenine–Thymine (AT) Base Pairs and Their Mimics " Our quantum chemicalbonding analyses shatter atextbook model. We prove resonance-assisted hydrogen bonding is not the reason for the enhanced H-bond strength between two sp 2-hybridized monomers, such as adenine and thy-mine. " Learn more about the story behind the research featured on the front cover in this issue's Cover Profile. Read the corresponding article on p. 318 ff. is amultidisciplinary,gold-road, open-access, international forum forthe publication of Reviews, Full Papersand Communications from all areas of chemistry and related fields. ChemistryOpen also publishes the Thesis Treasury containing summaries of Ph.D. theses andlinks to the full version via our homepage. Based in Europe, ChemistryOpen attracts authors and readers from around the world, as open-access publishing becomes more important in all areas of chemistry. ChemistryOpen is co-owned by ChemPubSocEurope and published by Wiley-VCH. Authorscan submit their review articles, primary research articles and thesis summaries via our homepage by clicking " submit an article " .All contributionsconsidered suitable for publication are subjecttopeer review,and if accepted, electronically processed andpublished online ensuring high quality and short publication times. Most of the articles in this issue have already appeared online on wileyonlinelibrary.com.