String quartets: Guanine molecules self‐assemble into a hydrogen‐bonded network of G quartets upon deposition under ultrahigh vacuum conditions onto Au(111) surfaces as shown by STM (see picture). The resilience of the H‐bonded network (stable up to 400 K) is explained through a cooperative increase in the strength of H‐bonds between guanine molecules in a quartet.

STM manipulation is used to directly probe the hierarchy of bond‐strengths involved in the self‐assembly of multifunctional molecules, which can thus be used to help to identify particular features of the molecular architecture in the observed STM images (see picture).

Gemeinsam sind wir stark: Guaninmoleküle bilden bei der Abscheidung im Ultrahochvakuum auf Au(111)‐Oberflächen spontan ein H‐Brücken‐gebundenes Netzwerk aus G‐Quartetten, wie STM‐Aufnahmen belegen (siehe Bild). Die Unverwüstlichkeit des Netzwerks (bis 400 K stabil) wird mit einer kooperativen Zunahme der Stärke der H‐Brücken zwischen Guaninmolekülen in einem Quartett erklärt.

From the interplay of scanning tunneling microscopy and theoretical calculations, we study the chiral self-assembly of achiral HtB-HBC molecules upon adsorption on the Cu(110) surface. We find that chirality is expressed at two different levels: a +/-5 degrees rotation of the molecular axis with respect to the close-packed direction of the Cu(110) substrate and a chiral close-packed arrangement expected for star-shaped molecules in 2D. Out of the four possible chiral expressions, only two are found to exist due the effect of van der Waals (vdW) interactions forcing the molecules to simultaneously adjust to the atomic template of the substrate geometry and self-assemble in a close-packed geometry.