title: Dense or porous packing? Two-dimensional self-assembly of star-shaped mono-, bi-, and terpyridine derivatives.
abstract: The self-assembly behavior of five star-shaped pyridyl-functionalized 1,3,5-triethynylbenzenes was studied at the interface between an organic solvent and the basal plane of graphite by scanning tunneling microscopy. The mono- and bipyridine derivatives self-assemble in closely packed 2D crystals, whereas the derivative with the more bulky terpyridines crystallizes with porous packing. DFT calculations of a monopyridine derivative on graphene, support the proposed molecular model. The calculations also reveal the formation of hydrogen bonds between the nitrogen atoms and a hydrogen atom of the neighboring central unit, as a small nonzero tunneling current was calculated within this region. The title compounds provide a versatile model system to investigate the role of multivalent steric interactions and hydrogen bonding in molecular monolayers.
authors: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin (Germany); Current address: Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3TA (UK).
authors: Daniel
authors: D
authors: Trawny
authors: Philomena
authors: P
authors: Schlexer
authors: Krista
authors: K
authors: Steenbergen
authors: Jürgen P
authors: JP
authors: Rabe
authors: Beate
authors: B
authors: Paulus
authors: Hans-Ulrich
authors: HU
authors: Reissig
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D001555:Benzene Derivatives / Q000737:chemistry*; D006860:Hydrogen Bonding; D016252:Microscopy, Scanning Tunneling; D008958:Models, Molecular; D016062:Porosity; D011725:Pyridines / Q000737:chemistry*
chemical_list: D001555:Benzene Derivatives; D011725:Pyridines; D015082:2,2'-Dipyridyl; C013278:2,2',2''-terpyridine; C023666:pyridine
keywords: density functional calculations; graphene; nitrogen heterocycles; scanning probe microscopy; self-assembly