title: Isoreticular two-dimensional covalent organic frameworks synthesized by on-surface condensation of diboronic acids.
abstract: On-surface self-condensation of 1,4-benzenediboronic acid was previously shown to yield extended surface-supported, long-range-ordered two-dimensional covalent organic frameworks (2D COFs). The most important prerequisite for obtaining high structural quality is that the polycondensation (dehydration) reaction is carried out under slightly reversible reaction conditions, i.e., in the presence of water. Only then can the subtle balance between kinetic and thermodynamic control of the polycondensation be favorably influenced, and defects that are unavoidable during growth can be corrected. In the present study we extend the previously developed straightforward preparation protocol to a variety of para-diboronic acid building blocks with the aim to tune lattice parameters and pore sizes of 2D COFs. Scanning tunneling microscopy is employed for structural characterization of the covalent networks and of noncovalently self-assembled structures that form on the surface prior to the thermally activated polycondensation reaction.
authors: Deutsches Museum , Museumsinsel 1, 80538 Munich, Germany, and TUM School of Education, Technical University of Munich, Schellingstrasse 33, 80799 Munich, Germany.
authors: Jürgen F
authors: JF
authors: Dienstmaier
authors: Dana D
authors: DD
authors: Medina
authors: Mirjam
authors: M
authors: Dogru
authors: Paul
authors: P
authors: Knochel
authors: Thomas
authors: T
authors: Bein
authors: Wolfgang M
authors: WM
authors: Heckl
authors: Markus
authors: M
authors: Lackinger
mesh_terms: D000327:Adsorption; D001897:Boronic Acids / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D009930:Organic Chemicals / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D001897:Boronic Acids; D046911:Macromolecular Substances; D009930:Organic Chemicals