Structural Phase Transitions of Molecular Self-Assembly Driven by Nonbonded Metal Adatoms
- 26 May 2020
- journal article
- research article
- Published by American Chemical Society (ACS) in ACS Nano
- Vol. 14 (5), 6331-6338
- https://doi.org/10.1021/acsnano.0c02995
Abstract
The involvement of metal atoms in molecular assemblies has enriched the structural and functional diversity of two-dimensional supramolecular networks, where metal atoms are incorporated into the architecture via coordination or ionic bonding. Here we present a temperature-variable study of the self-assembly of the 1,3,5-tribromobenzene (TriBB) molecule on Cu(111) that reveals the involvement of non-bonded adatoms in the molecular matrix. By means of scanning tunneling microscopy and noncontact atomic force microscopy, we demonstrate the molecular-level details of a phase transition of TriBB assembly from the close-packed to porous honeycomb structures at 78 K. This is an unexpected transformation because the close-packed phase is thermodynamically favored in view of its higher molecular density and more intermolecular bonds as compared to the honeycomb lattice. A comprehensive density functional theory calculation suggests that Cu adatoms should be involved in the formation of the honeycomb network, where the Cu adatoms help stabilize the molecular assembly via enhanced van der Waals interactions between TriBB molecules and the underlying substrate. Both calculation and experimental results suggest no chemical bonding or direct charge transfer between the adatoms and the molecules, thus the electronic characteristics of the Cu adatoms trapped in the molecular confinement are close to the intrinsic ones on a clean metal surface and different from those in the traditional coordination-bonded framework. The nonbonded metal adatoms embedded self-assemblies may complement the metal-organic coordination system and can be used to tailor the chemical reactivity and electronic properties of supramolecular structures.Keywords
Funding Information
- National Natural Science Foundation of China (21425310, 21688102, 21721002, 21790353, 21972032, 91427301)
- CAS-PKU Pioneer Cooperation Team
- The Strategic Priority Research Program of Chinese Academy of Sciences (XDB36000000)
- the Ministry of Science and Technology of China (2016YFA0200700, 2017YFA0205000, 2018YFA0208600)
- Shanghai Pujiang Program (19PJ1400600)
- the Science Challenge Project (TZ2018004)
This publication has 32 references indexed in Scilit:
- The Chemistry and Applications of Metal-Organic FrameworksScience, 2013
- Substrate Templating upon Self‐Assembly of Hydrogen‐Bonded Molecular Networks on an Insulating SurfaceSmall, 2012
- Single-Molecule Resolution of an Organometallic Intermediate in a Surface-Supported Ullmann Coupling ReactionJournal of the American Chemical Society, 2011
- Material- and Orientation-Dependent Reactivity for Heterogeneously Catalyzed Carbon−Bromine Bond HomolysisThe Journal of Physical Chemistry C, 2010
- Localization of the Cu(111) Surface State by Single Cu AdatomsPhysical Review Letters, 2004
- Triangular Halogen−Halogen−Halogen Interactions as a Cohesive Force in the Structures of TrihalomesitylenesCrystal Growth & Design, 2002
- From ultrasoft pseudopotentials to the projector augmented-wave methodPhysical Review B, 1999
- Decay of Cu adatom islands on Cu(111)Surface Science, 1998
- Efficient iterative schemes forab initiototal-energy calculations using a plane-wave basis setPhysical Review B, 1996
- Ab initiomolecular dynamics for liquid metalsPhysical Review B, 1993