The co-adsorption of trinitrotoluene (TNT), a typical π-electron acceptor, and triphenylene (TP), a typical π-electron donor, on a Au(111) surface was investigated by in situ Electrochemical Scanning Tunneling Microscopy (ECSTM). DFT calculations proved that parallelly stacked and well-overlapped TP and TNT molecules can form Donor-Acceptor dyads through intermolecular π-π charge transfer, which agree well with the experimental results in the present work.
View Article and Find Full Text PDFSpontaneous symmetry-breaking of a racemic mixture of supramolecular triginal prisms into chiral domains on a Au(111) surface is observed by scanning tunneling microscopy (STM). High-resolution STM analysis enables the structural aspects of each enantiomeric domain to be elucidated. The ability to resolve chirality on achiral surfaces has potential applications in heterogeneous stereoselective synthesis and catalysis.
View Article and Find Full Text PDFElectrochemistry and adlayer structure of trinitrotoluene (TNT) on an Au(111) electrode were investigated using cyclic voltammetry and in situ electrochemical scanning tunneling microscopy (ECSTM).
View Article and Find Full Text PDFThe adlayers formed by a series of aza- and/or oxo-bridged calix[2]arene[2]triazines on Au(111) surfaces were investigated by scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. 1,3-Alternate configurations of these molecules are preserved on gold surfaces as in their three-dimensional crystals. STM images show that the cavity sizes of these molecules are finely tuned by substituting the bridging nitrogen atom with oxygen atoms, which change the strengths and densities of the intermolecular hydrogen bonds.
View Article and Find Full Text PDFTwo alkyl-substituted dual oligothiophenes, quarterthiophene (4T)-trimethylene (tm)-octithiophene (8T) and 4T-tm-4T, were used to fabricate molecular structures on highly oriented pyrolytic graphite and Au(111) surfaces. The resulted structures were investigated by scanning tunneling microscopy. The 4T-tm-8T and 4T-tm-4T molecules self-organize into long-range ordered structures with linear and/or quasi-hexagonal patterns on highly oriented pyrolytic graphite at ambient temperature.
View Article and Find Full Text PDFThis report demonstrates a novel electrochemical method for fast and sensitive detection of ultra-trace 2,4,6-trinitrotoluene (TNT) based on modified electrodes by functionalized MWCNTs. To fabricate new kind of functionalized MWCNTs material sensitive to TNT, our work first theoretically investigated the interaction between triphenylene (TP) and TNT by calculating their electrostatic potentials, and secondly characterized this interaction by the fluorescence spectra. The functionalized MWCNTs of TP-MWCNTs were thoroughly characterized by fluorescence and UV-visible spectra, and by analysing these results, the interaction between TP and MWCNTs was also examined.
View Article and Find Full Text PDFUV light irradiation effect on the structural transformation in a self-assembled monolayer of 4-(amyloxy)cinnamic acid (AOCA) on Au(111) has been investigated by using electrochemical scanning tunneling microscopy (ECSTM), cyclic voltammetry, and infrared (IR) spectroscopy. A well-defined 4-(amyloxy)cinnamic acid adlayer with a (4 x 11) symmetry was first prepared on Au(111). After UV-light irradiation onto the adlayer, a new adlayer is observed with different molecular arrangement and a symmetry of (5 x 8).
View Article and Find Full Text PDFThe effect of the molecular structure on the self-assembly of specially designed two-core 1,3,2-dioxaborines has been studied with various techniques. It was found that the molecules spontaneously adsorbed on HOPG surfaces and self-organized into well-ordered two-dimensional (2D) monolayers. The structural details of the 2D assemblies were investigated by scanning tunneling microscopy (STM).
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