Fig. 1: Charge distribution of halogen benzenes, scheme of type II halogen bonds, and bonding configurations on Cu(111) and Au(111).
From: Surface-controlled reversal of the selectivity of halogen bonds
a Electrostatic potential (ESP) at the 10−3 e bohr−3 charge density isosurface as calculated by DFT of bromobenzene (C6H5Br) and iodobenzene (C6H5I) in gas phase and on Cu(111). The contribution of the substrate has been removed (see “Methods”). The “negative belts” and the “σ-holes” appear as red and blue regions, respectively (indicated by red “−” and blue “+” signs). b Schematic drawings of type II halogen bonds with effective bonding angles of 90° (upper part) and 120° (lower part), respectively. The effective bonding angles (θeff = −180° + θ1 + θ2) are measured between the C–X axes as indicated by black arrows. Black dotted lines between the positive σ-hole (blue region) and the negative belt (red region) of neighboring halogens are indicating the halogen bonds. c, d Sketch of observed molecular assemblies on the reactive Cu(111) and the inert Au(111) surface indicating the control over the bonding configuration and the selectivity.
