TWO-DIMENSIONAL SELF-ASSEMBLY OF SUPRAMOLECULAR STRUCTURES

2000 ◽  
Vol 07 (05n06) ◽  
pp. 661-666 ◽  
Author(s):  
MATTHIAS BÖHRINGER ◽  
WOLF-DIETER SCHNEIDER ◽  
RICHARD BERNDT
Keyword(s):  
Self Assembly ◽  
Electrostatic Interactions ◽  
Gold Surface ◽  
Two Dimensions ◽  
Molecular Structures ◽  
The Self ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Tunneling Microscopy ◽  
Chiral Phase

We briefly review recent low temperature scanning tunneling microscopy (STM) investigations performed in our laboratory1–5 on the self-assembly of the dipolar organic molecule 1-nitronaphthalene (NN) adsorbed on the reconstructed Au(111) surface. NN becomes chiral upon planar adsorption on the gold surface. We observe several coverage-driven structural transformations which are associated with simultaneous changes in the enantiomeric composition of the self-assembled molecular structures. At low coverages almost exclusively decamers with an 8:2 ratio of the enantiomers are formed. In a medium coverage range enantiopure one-dimensional molecular double chains prevail on the surface. Subsequently, molecules with opposite handedness are admixed until at monolayer coverage racemic one- and two-dimensional structures coexist. Modeling shows that hydrogen bonding causes the observed self-assembly. A subtle interplay between the electrostatic interactions among the molecules and their interaction with the reconstructed metal surface is the origin of the observed coverage-driven chiral phase transition in two dimensions.

scholarly journals Potential Driven Non-Reactive Phase Transitions of Ordered Porphyrin Molecules on Iodine-Modified Au(100): An Electrochemical Scanning Tunneling Microscopy (EC-STM) Study

Surfaces ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 12-28 ◽  
Author(s):  
Tomasz Kosmala ◽  
Matías Blanco ◽  
Gaetano Granozzi ◽  
Klaus Wandelt
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Long Range ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
The Self ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Electrode Potentials ◽  
Electrochemical Scanning Tunneling Microscopy

The modelling of long-range ordered nanostructures is still a major issue for the scientific community. In this work, the self-assembly of redox-active tetra(N-methyl-4-pyridyl)-porphyrin cations (H2TMPyP) on an iodine-modified Au(100) electrode surface has been studied by means of Cyclic Voltammetry (CV) and in-situ Electrochemical Scanning Tunneling Microscopy (EC-STM) with submolecular resolution. While the CV measurements enable conclusions about the charge state of the organic species, in particular, the potentio-dynamic in situ STM results provide new insights into the self-assembly phenomena at the solid-liquid interface. In this work, we concentrate on the regime of positive electrode potentials in which the adsorbed molecules are not reduced yet. In this potential regime, the spontaneous adsorption of the H2TMPyP molecules on the anion precovered surface yields the formation of up to five different potential-dependent long-range ordered porphyrin phases. Potentio-dynamic STM measurements, as a function of the applied electrode potential, show that the existing ordered phases are the result of a combination of van der Waals and electrostatic interactions.

MOLECULAR TEMPLATES FOR CONTROLLING AND ORDERING ORGANIC MOLECULES ON SOLID SURFACES

NANO ◽  
2012 ◽  
Vol 07 (01) ◽  
pp. 1230001 ◽  
Author(s):  
XU ZHANG ◽  
SHAN-SHAN LI ◽  
TING CHEN ◽  
DONG WANG ◽  
LI-JUN WAN
Keyword(s):  
Self Assembly ◽  
Organic Molecules ◽  
Molecular Engineering ◽  
Molecular Structures ◽  
Solid Surfaces ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Tunneling Microscopy ◽  
Ordered Assembly ◽  
Template Design

Molecular templates are effective for inducing the formation of functional organic molecular structures on solid surfaces. Various surface nanopatterns as molecular templates were developed by self-assembly and molecular engineering. These molecular templates were used and led to the formation of ordered assembly of alien species into designed two-dimensional matrices targeting at future applications. Both molecular template and so-fabricated nanopatterned assembly were clearly observed by scanning tunneling microscopy (STM). This paper summarizes some recent results on molecular templates for controlling and ordering organic molecules on solid surfaces mainly from our group. Several typical molecular templates and the consequent nanofabrication of ordered assemblies are described, including template design and fabrication, molecule ordering and patterning with the template as well as the possible application of these systems.

Self-assembly of a nickel(II) pseudorotaxane nanostructure on a gold surface

2007 ◽  
Vol 79 (6) ◽  
pp. 1077-1085 ◽  
Author(s):  
Agnieszka Więckowska ◽  
Marta Wiśniewska ◽  
Marcin Chrzanowski ◽  
Jarosław Kowalski ◽  
Bohdan Korybut-Daszkiewicz ◽  
...  
Keyword(s):  
Self Assembly ◽  
Gold Surface ◽  
Molecular Switches ◽  
Macrocyclic Complex ◽  
The Self ◽  
Scanning Tunneling ◽  
Thiol Groups ◽  
Tunneling Microscopy ◽  
Assembly Method ◽  
Intramolecular Motion

Tetraazamacrocyclic complexes of NiII and CuII can be used as components of catenanes or rotaxanes showing electrochemically switched intramolecular motion in solution. In our present studies, we modify these compounds with organothiol chains to attach them to the surface of the electrode using the self-assembly method and employ them next as molecular switches, which change conductivity upon applying appropriate potential. The electrochemical properties of these compounds are studied in the solution and, in the case of thiol derivative, immobilized on the electrode surface. The macrocyclic complex of NiII, immobilized on the Au surface, forms the axis of the rotaxane. This compound can be anchored to the surface by one or two thiol groups. The data obtained from scanning tunneling microscopy (STM) experiments using colloidal Au confirm that the orientation normal to the surface dominates. The electrochemical experiments reveal reversible one-electron oxidation of metal center from +2 to +3. The behavior of the electrode modified with the macrocyclic complex of NiII upon immersion in a solution containing bismacrocyclic complex of NiII points to the formation of a new rotaxane-like nanostructure on the surface of the electrode.

scholarly journals Au(100) as a Template for Pentacene Monolayer

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2393
Author(s):  
Artur Trembułowicz ◽  
Agata Sabik ◽  
Miłosz Grodzicki
Keyword(s):  
Self Assembly ◽  
Molecular Layer ◽  
High Vacuum ◽  
Gold Surface ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Height Difference ◽  
Characteristic Features ◽  
Reconstructed Surface

The surface of quasi-hexagonal reconstructed Au(100) is used as the template for monolayer pentacene (PEN) self-assembly. The system is characterized by means of scanning tunneling microscopy at room temperature and under an ultra-high vacuum. A new modulated pattern of molecules with long molecular axes (MA) arranged along hex stripes is found. The characteristic features of the hex reconstruction are preserved herein. The assembly with MA across the hex rows leads to an unmodulated structure, where the molecular layer does not recreate the buckled hex phase. The presence of the molecules partly lifts the reconstruction—i.e., the gold hex phase is transformed into a (1×1) phase. The arrangement of PEN on the gold (1×1) structure is the same as that of the surrounding molecular domain on the reconstructed surface. The apparent height difference between phases allows for the distinction of the state of the underlying gold surface.

scholarly journals STM study on the self-assembly of oligothiophene-based organic semiconductors

2011 ◽  
Vol 2 ◽  
pp. 802-808 ◽  
Author(s):  
Elena Mena-Osteritz ◽  
Marta Urdanpilleta ◽  
Erwaa El-Hosseiny ◽  
Berndt Koslowski ◽  
Paul Ziemann ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Self Assembly ◽  
Theoretical Calculations ◽  
The Self ◽  
Scanning Tunneling ◽  
Ambient Conditions ◽  
Tunneling Microscopy ◽  
Substitution Pattern ◽  
Electronic Density ◽  
The Individual

The self-assembly properties of a series of functionalized regioregular oligo(3-alkylthiophenes) were investigated by using scanning tunneling microscopy (STM) at the liquid–solid interface under ambient conditions. The characteristics of the 2-D crystals formed on the (0001) plane of highly ordered pyrolitic graphite (HOPG) strongly depend on the length of the π-conjugated oligomer backbone, on the functional groups attached to it, and on the alkyl substitution pattern on the individual thiophene units. Theoretical calculations were performed to analyze the geometry and electronic density of the molecular orbitals as well as to analyze the intermolecular interactions, in order to obtain models of the 2-D molecular ordering on the substrate.

Scanning Tunneling Microscopy Study of α,ω-Dihexylsexithiophene Adlayers on Au(111): A Chiral Separation Induced by a Surface

2012 ◽  
Vol 18 (4) ◽  
pp. 885-891 ◽  
Author(s):  
Yonghai Song ◽  
Yu Wang ◽  
Lingli Wan ◽  
Shuhong Ye ◽  
Haoqing Hou ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Self Assembly ◽  
Room Temperature ◽  
Three Dimensional ◽  
Microscopy Study ◽  
Molecular Structures ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Left Handed ◽  
Bulk Structure

AbstractThe self-assembly of α,ω-dihexylsexithiophene molecules on an Au(111) surface was examined by using scanning tunneling microscopy at room temperature, revealing the internal molecular structures of the sexithiophene backbones and the hexyl side chains. The α,ω-dihexylsexithiophene formed a large and well-ordered monolayer in which the molecule lay flatly on the Au(111) surface and was separated into two chiral domains. A detailed observation reveals that the admolecules were packed in one lamellae with their molecular axis aligned along the main axis of the Au(111) substrate with their hexyl chains deviated from ⟨110⟩ direction of the Au(111) substrate by 12 ± 0.5°. In contrast to the behavior in the three-dimensional bulk structure, flat-lying adsorption introduced molecular chirality: right- and left-handed molecules separate into domains of two different orientations, which are mirror symmetric with respect to the ⟨121⟩ direction of the Au(111) substrate. Details of the adlayer structure and the chiral self-assembly were discussed here.

scholarly journals Realizing Two-Dimensional Spin Arrays on Surfaces via Halogen-Bonding Molecular Self-Assembly

2021 ◽  
Author(s):  
Dingguan Wang ◽  
Zishen Wang ◽  
Shaofei Wu ◽  
Arramel Arramel ◽  
Xinmao Yin ◽  
...  
Keyword(s):  
Single Molecule ◽  
Self Assembly ◽  
Halogen Bonding ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Halogen Bonds ◽  
Tunneling Microscopy ◽  
Single Molecule Level ◽  
Magnetic Devices ◽  
Temperature Scanning

Well-ordered spin arrays are highly desirable for next-generation molecule-based magnetic devices, and yet its synthetic method remains a challenging task. Herein, we demonstrate the realization of two-dimensional supramolecular spin arrays on surfaces via halogen-bonding molecular self-assembly. A bromine-terminal perchlorotriphenymethyl radical with net carbon spin was synthesized and deposited on Au(111) to achieve two-dimensional supramolecular spin arrays. By taking advantage of the diversity of halogen bonds, five supramolecular spin arrays are presented with ultrahigh spin densities (up to the value of 3 × 10<sup>13</sup> spins at the size of a flash drive), as probed by low-temperature scanning tunneling microscopy at the single-molecule level. First principle calculations verify that the formation of three distinct types of halogen bonds can be used to tailor supramolecular phases via molecular coverage and annealing temperature. Our work demonstrates supramolecular self-assembly as a promising method to engineering 2D spin arrays for potential application in magnetic devices.

scholarly journals Halogen Bonds Fabricate 2D Molecular Self-Assembled Nanostructures by Scanning Tunneling Microscopy

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1057
Author(s):  
Yi Wang ◽  
Xinrui Miao ◽  
Wenli Deng
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Self Assembly ◽  
Density Functional ◽  
Deep Understanding ◽  
Halogen Bonding ◽  
The Self ◽  
Scanning Tunneling ◽  
Halogen Bonds ◽  
Tunneling Microscopy ◽  
Self Assembled

Halogen bonds are currently new noncovalent interactions due to their moderate strength and high directionality, which are widely investigated in crystal engineering. The study about supramolecular two-dimensional architectures on solid surfaces fabricated by halogen bonding has been performed recently. Scanning tunneling microscopy (STM) has the advantages of realizing in situ, real-time, and atomic-level characterization. Our group has carried out molecular self-assembly induced by halogen bonds at the liquid–solid interface for about ten years. In this review, we mainly describe the concept and history of halogen bonding and the progress in the self-assembly of halogen-based organic molecules at the liquid/graphite interface in our laboratory. Our focus is mainly on (1) the effect of position, number, and type of halogen substituent on the formation of nanostructures; (2) the competition and cooperation of the halogen bond and the hydrogen bond; (3) solution concentration and solvent effects on the molecular assembly; and (4) a deep understanding of the self-assembled mechanism by density functional theory (DFT) calculations.

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