Diboraperylene Diborinic Acid Self‐Assembly on Ag(111)—Kagome Flat Band Localized States Imaged by Scanning Tunneling Microscopy and Spectroscopy
W.‐H. PAN, Carina Mützel, Soumyajyoti Haldar, Hendrik Hohmann, Stefan Heinze, Jeffrey M. Farrell, Ronny Thomale, M. Bode, Frank Würthner, Jing Qi
Abstract
Abstract Replacement of sp 2 ‐hybridized carbon in polycyclic aromatic hydrocarbons (PAHs) by boron affords electron‐deficient π‐scaffolds due to the vacant p z ‐orbital of three‐coordinate boron with the potential for pronounced electronic interactions with electron‐rich metal surfaces. Using a diboraperylene diborinic acid derivative as precursor and a controlled on‐surface non‐covalent synthesis approach, we report on a self‐assembled chiral supramolecular kagome network on an Ag(111) surface stabilized by intermolecular hydrogen‐bonding interactions at low temperature. Scanning tunneling microscopy (STM) and spectroscopy (STS) reveal a flat band at ca. 0.33 eV above the Fermi level which is localized at the molecule center, in good agreement with tight‐binding model calculations of flat bands characteristic for kagome lattices.