Using a toolkit of theoretical techniques comprising ab initio density functional theory calculations, the nudged elastic band method and kinetic Monte Carlo (KMC) modeling, we investigate in great detail how para-terphenyl-meta-dicarbonitrile (pTmDC) molecules diffuse and isomerize to self-assemble on the Ag(111) surface. We show that molecules "walk" on the surface via a pivoting mechanism moving each of its two "legs" one at a time. We then identify a peculiar "under-side" isomerization mechanism capable of changing the molecules chirality, and demonstrate that it is fundamental in understanding the growth of hydrogen bonding assembles of ribbons, linkers, clusters and brickwall islands on the Ag(111) surface, as observed in recent scanning tunneling microscopy experiments (ChemPhysChem, 2010, 11, 1446). The discovered underlying atomistic mechanism of self-assembly may be behind the growth of other hydrogen bonding structures of chiral molecules on metal surfaces.
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http://dx.doi.org/10.1039/c5cp00220f | DOI Listing |
J Phys Chem C Nanomater Interfaces
January 2025
Technical University of Munich, TUM School of Natural Sciences, Physics Department E20, Garching 85748, Germany.
Metalloporphyrins on interfaces offer a rich playground for functional materials and hence have been subjected to intense scrutiny over the past decades. As the same porphyrin macrocycle on the same surface may exhibit vastly different physicochemical properties depending on the metal center and its substituents, it is vital to have a thorough structural and chemical characterization of such systems. Here, we explore the distinctions arising from coverage and macrocycle substituents on the closely related ruthenium octaethyl porphyrin and ruthenium tetrabenzo porphyrin on Ag(111).
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Clausius Institut für Physikalische und Theoretische Chemie, Universität Bonn, Bonn 53115, Germany.
The carpet growth of alkali halide (AH) layers across step edges of substrates enables the growth of seamless and continuous large domains. Yet, information about how the AH layer adapts continuously to the height difference between the terraces on the two sides of a step is only described by continuum models, which do not give details of the ionic displacements. Here, we present a first study of thin epitaxial KCl(100) layers grown on the Ag(111) surface by scanning tunneling microscopy that provides atomistic details for the first time.
View Article and Find Full Text PDFChemistry
January 2025
Ruhr University Bochum: Ruhr-Universitat Bochum, Organic Chemistry II, GERMANY.
It is well established that the confinement of reactants to two dimensions influences their reactivity. However, such confinement is often dominated by charge transfer effects between the reactants and the confining walls, in particular if the walls are conductive. Also, the reactivity of carbenes on metal surfaces is significantly affected by the charge transfer between the carbene and the metal, rendering the carbene more nucleophilic or electrophilic.
View Article and Find Full Text PDFAcc Chem Res
January 2025
Laboratory for Chemistry and Life Science (CLS), Institute of Integrated Research, Institute of Science Tokyo, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
ConspectusThe design of properties and functions of molecular assemblies requires not only a proper choice of building blocks but also control over their packing arrangements. A highly versatile unit in this context is a particular type of triptycene with substituents at the 1,8,13-positions, called tripodal triptycene, which offers predictable molecular packing and multiple functionalization sites, both at the opposite 4,5,16- or 10 (bridgehead)-positions. These triptycene building blocks are capable of two-dimensional (2D) nested hexagonal packing, leading to the formation of 2D sheets, which undergo one-dimensional (1D) stacking into well-defined "2D+1D" structures.
View Article and Find Full Text PDFACS Nano
January 2025
Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany.
The reduced dimensionality of thin transition metal dihalide films on single-crystal surfaces unlocks a diverse range of magnetic and electronic properties. However, achieving stoichiometric monolayer islands requires precise control over the growth conditions. In this study, we employ scanning probe microscopy to investigate the growth of MnI on Ag(111) via single-crucible evaporation.
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