title: The Role of Aromaticity, Hybridization, Electrostatics, and Covalency in Resonance-Assisted Hydrogen Bonds of Adenine-Thymine (AT) Base Pairs and Their Mimics.
abstract: Invited for this issues cover are Dr. Célia Fonseca Guerra from the VU University of Amsterdam and her collaborators at the University of Girona. The cover picture shows H-bonds in the adenine-thymine Watson-Crick base pair. An essential part of these H-bonds is their covalent component arising from donor-acceptor interactions between N or O lone pairs and the N-H antibonding σ* acceptor orbital. This charge-transfer interaction is represented by green figures walking on the pedestrian crossing, connecting the bases. This covalent component is the reason why H-bonds between DNA and/or unsaturated 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 a proper bonding mechanism, but also fails to explain the trend in stability. For more details, see the Full Paper on p. 318 ff.
authors.affiliation: Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Girona 17071, Girona, Spain.
authors.forename: Laia
authors.initials: L
authors.lastname: Guillaumes
authors.affiliation: Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Girona 17071, Girona, Spain.
authors.forename: Sílvia
authors.initials: S
authors.lastname: Simon
authors.affiliation: Department of Theoretical Chemistry and, Amsterdam Center for Multiscale Modeling, VU University Amsterdam De Boelelaan 1083, 1081 HV, Amsterdam, The Netherlands.
authors.forename: Célia
authors.initials: C
authors.lastname: Fonseca Guerra