Surface-assisted coordination chemistry and self-assembly

Abstract

This article discusses different approaches to build up supramolecular nanoarchitectures on surfaces, which were simultaneously investigated by scanning tunneling microscopy (STM) on the single-molecule level. Following this general road map, first, the hydrogen-bonding guided self-assembly of two different, structural-equivalent molecular building blocks, azobenzene dicarboxylic acid and stilbene dicarboxylic acid, was studied. Secondly, the coordination chemistry of the same building blocks, now acting as ligands in metal coordination reactions, towards co-sublimed Fe atoms was studied under near surface-conditions. Extended two-dimensional tetragonal network formation with unusual Fe2L(4/2)-dimers at the crossing points was observed on copper surfaces. Complementary to the first two experiments, a two-step approach based on the solution-based self-assembly of square-like tetranuclear complexes of the M4L4-type with subsequent deposition on graphite surfaces was investigated. One- and two-dimensional arrangements as well as single molecules of the M4L4-complexes could be observed. Moreover, the local electronic properties of a single M4L4-complexes could be probed with submolecular resolution by means of scanning tunnelling spectroscopy (STS).

Two-dimensional metal-organic coordination networks of Mn-7,7,8,8-tetracyanoquinodimethane assembled on Cu(100): Structural, electronic, and magnetic properties

“…A unique way to study metal coordination is through surfaceassisted coordination assembly. [8][9][10] On two-dimensional ͑2D͒ surfaces, due to surface confinement, the formation of novel 2D coordination systems has been demonstrated. [11][12][13][14] In this paper we present results of the assembly of two-dimensional Mn͑TCNQ͒ 2 coordination networks on a Cu͑100͒ surface.…”

Adsorption of cobalt (II) 5,10,15,20-tetrakis(2-aminophenyl)-porphyrin onto copper substrates: Characterization and impedance studies for corrosion inhibition

“…The modified surface blocks the approach of electrochemically active species to the electrode surface, resulting in a complete suppression of their redox reactions at the electrode surface. The corrosion inhibition will be prominent in organic molecules due to their higher resistivity to electron transfer reactions [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. They form a thin resistive layer on the metal surface and protect it from the surrounding reactive environment.…”

Self-recognition and self-selection in multicomponent supramolecular coordination networks on surfaces

“…Despite the possibility to form homotopic carboxylate-Fe coordination, the preference of the heterotopic coordination mode over homotopic or alternative structures demonstrates the robustness of the [(Fe 2 ) (1) 2/2 (2) 2/2 ] n coordination motif. The ligands follow the principle of ''maximal site occupancy'' by realizing metal coordination at all available sites (1, 16); however, this is not fully achieved by the iron centers, because apical coordination is obviously impossible due to the specific steric demands at the surface (17,18).…”