scholarly journals Polymorphic self-assembly of pyrazine-based tectons at the solution–solid interface

2019 ◽  
Vol 10 ◽  
pp. 494-499
Author(s):  
Achintya Jana ◽  
Puneet Mishra ◽  
Neeladri Das
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Building Blocks ◽  
Molecular Structures ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Equal Distribution ◽  
Solid Interface ◽  
Supramolecular Architectures ◽  
Microscopy Investigation

Exploring the surface self-assembly of small molecules that act as building blocks (tectons) for complex supramolecular structures is crucial for realizing surface-supported functional molecular devices. Here, we report on the synthesis and surface self-assembly of a new pyrazine-derived molecule with pyridine pendants. Ambient scanning tunneling microscopy investigation at the solution–solid interface reveals polymorphic self-assembly of these molecules on a HOPG substrate. Two different molecular packing structures with equal distribution are observed. Detailed analysis of the STM images emphasizes the crucial role of weak intermolecular hydrogen bonding, and molecule–substrate interactions in the formation of the observed polymorphs. Such weak hydrogen bonding interactions are highly desirable for the formation of modular supramolecular architectures since they can provide sufficiently robust molecular structures and also facilitate error correction.

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.

Supramolecular Chemistry at the Liquid/Solid Interface a Scanning Tunneling Microscopy Approach

2007 ◽  
Vol 121-123 ◽  
pp. 369-372
Author(s):  
S. de Feyter ◽  
A. Miura ◽  
H. Uji-i ◽  
P. Jonkheijm ◽  
A.P.H.J. Schenning ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Scanning Tunneling Microscopy ◽  
Supramolecular Chemistry ◽  
Organic Molecules ◽  
Molecular Conformation ◽  
Scanning Tunneling ◽  
Conjugated Oligomers ◽  
Two Dimensional ◽  
Tunneling Microscopy ◽  
Solid Interface

With scanning tunneling microscopy (STM), the intramolecular conformational and intermolecular ordering aspects have been investigated of a variety of organic molecules physisorbed at the liquid-solid interface. By balancing the interplay between intramolecular and intermolecular interactions (hydrogen bonding), leading to control of the molecular conformation, foldamers were created which order into well-defined two-dimensional crystals. The nature of the hydrogen bonding groups in conjugated oligomers leads to the formation of infinite stacks and cyclic multimers, expressing the chiral nature of the molecules.

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.

CHIRAL SUPRAMOLECULAR SELF-ASSEMBLY OF 2,2’:6’,2”-TERPYRIDINE-4’-CARBOXYLIC ACID MOLECULES CHEMICALLY ADSORBED ON Cu(111)

2016 ◽  
Vol 23 (06) ◽  
pp. 1650061 ◽  
Author(s):  
DANFENG JIANG ◽  
YAN LU ◽  
JIE LING ◽  
XINLI LENG ◽  
XIAOQING LIU ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Self Assembly ◽  
Density Functional ◽  
Nearest Neighbor ◽  
Building Blocks ◽  
Scanning Tunneling ◽  
Large Area ◽  
Tunneling Microscopy ◽  
Self Assembled Monolayer ◽  
Standing Up

In this paper, large-area chiral supramolecular self-assembly of 2,2’:6’,2”-terpyridine-4’-carboxylic acid (C[Formula: see text]H[Formula: see text]N3O2; Y) molecules on Cu(111) is studied using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. The basic building blocks of such a self-assembled monolayer are triangular vortex-shaped supramolecular structures containing three twisted Y molecules. Chirality is maintained and transferred from one vortex to the adjacent vortex in successive molecular domains within the same atomic terrace. The twisted Y molecule, bridging two nearest-neighbor Cu atoms, is stabilized by symmetric Cu–O bonds on the surface. The near perpendicularity of these bonds to the surface is the main reason for the formation of “standing-up” Y molecules.

The role of halogens in on-surface Ullmann polymerization

2017 ◽  
Vol 204 ◽  
pp. 453-469 ◽  
Author(s):  
Gianluca Galeotti ◽  
Marco Di Giovannantonio ◽  
Josh Lipton-Duffin ◽  
Maryam Ebrahimi ◽  
Stefano Tebi ◽  
...  
Keyword(s):  
Building Blocks ◽  
Molecular Structures ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Elastic Band ◽  
X Ray ◽  
Molecular Precursors ◽  
Diffusion Paths ◽  
Ullmann Coupling

Ullmann coupling is the most common approach to form surface-confined one- and two-dimensional conjugated structures from haloaryl derivatives. The dimensions of the formed nanostructures can be controlled by the number and location of halogens within the molecular precursors. Our study illustrates that the type of halogen plays an essential role in the design, orientation, and extent of the surface-confined organometallic and polymeric nanostructures. We performed a comparative analysis of five 1,4-dihalobenzene molecules containing chlorine, bromine, and iodine on Cu(110) using scanning tunneling microscopy, fast-X-ray photoelectron and near edge X-ray absorption fine structure spectroscopies. Our experimental data identify different molecular structures, reaction temperatures and kinetics depending on the halogen type. Climbing image nudged elastic band simulations further clarify these observations by providing distinct diffusion paths for each halogen species. We show that in addition to the structure of the building blocks, the halogen type has a direct influence on the morphology of surface-confined polymeric structures based on Ullmann coupling.

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.

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