Fig. 3: Bonding configurations of typical windmills and dimers on Cu(111) and Au(111).
From: Surface-controlled reversal of the selectivity of halogen bonds
a–c AFM constant-height images of a Br···Br···Br windmill structure of BrparaImeta-TP on Cu(111). b AFM image overlaid with structural models of BrparaImeta-TP. Crystallographic [\(\bar 12\bar 1\)] and [\(11\bar 2\)] directions of the Cu(111) lattice are indicated with red and blue arrows, respectively. c Zoom-in to central region of the cluster with bonding angles θ1 and θ2 and bond distance L of the halogen bonds. Each bromine is acting as a halogen bond donor and acceptor, respectively (see Fig. 1b). d–f AFM image and bonding configuration of a Br···Br dimer [BrparaImeta-TP on Cu(111)]. g–i AFM image and bonding configuration of a I···I dimer [IparaBrmeta-TP on Au(111)]. Parameters: oscillation amplitude 160 pm (a, d) and 170 pm (g), imaging distances are given with respect to the tunneling gap at U = 200 mV (a, d) and 100 mV (g) and I = 10 pA.
