Unraveling the molecular conformations of a single ruthenium complex adsorbed on the Ag(111) surface by calculations

Calculations have revealed the adsorption properties of the tris(dibenzoylmethanato)ruthenium (Ru(dbm)3) molecule on Ag(111).</p

Unraveling the molecular conformations of a single ruthenium complex adsorbed on the Ag(111) surface by calculations

International audienceThe tris(dibenzoylmethanato)ruthenium (Ru(dbm)3) molecule has recently been characterized by scanning tunneling microscopy (STM) experiments upon adsorption on Ag(111). The adsorbed Ru(dbm)3 molecule shows two conformations with respect to the [1-10] direction of the substrate, one with a three-lobed feature and the other one with a bi-lobed structure. For each of these structures, the molecule can take two geometries (states). Molecular mechanics calculations in a semi-empirical framework and STM calculated images reveal that these states on the substrate originate from the enantiomer of the Ru(dbm)3 molecule in the case of three-lobed structure and from the rotation of the two phenyls in the top dbm moities for the bi-lobed form

Calculated and structural analyses of self-assembly formed by [7]thiaheterohelicene-2,13-carboxaldehyde molecules on Au(111)

International audienceRecently, the electronic and structural properties of large self-assembled domains of [7]thiahetero- helicene-2,13-carboxaldehyde helicene ([7]TH-dial) molecules on Au(111), Cu(001), and NiAl(110) metal surfaces have been characterized by scanning tunneling microscopy (STM). Several distinct areas of the self-assembled structures can be observed. To describe and explore the morphology of and the interactions in these distinct self-assembled nanostructures, we combine the results obtained through calculations in a semi-empirical framework and calculated STM images. It is revealed that these supramolecular nanostructures, on metallic substrates, originate from the two orientations P and M of the [7]TH-dial molecules linked in different orientations (head-to-tail, sideways, head-on, and tail-on) through van der Waals interactions. The results presented here provide valuable insights for understanding the intermolecular and substrate–molecule interactions within the self-assembled nanostructures of [7]TH-dial molecules on metallic surfaces

Self-Assembly of Molecular Landers Equipped with Functional Moieties on the Surface: A Mini Review

The bottom-up fabrication of supramolecular and self-assembly on various substrates has become an extremely relevant goal to achieve prospects in the development of nanodevices for electronic circuitry or sensors. One of the branches of this field is the self-assembly of functional molecular components driven through non-covalent interactions on the surfaces, such as van der Waals (vdW) interactions, hydrogen bonding (HB), electrostatic interactions, etc., allowing the controlled design of nanostructures that can satisfy the requirements of nanoengineering concepts. In this context, non-covalent interactions present opportunities that have been previously explored in several molecular systems adsorbed on surfaces, primarily due to their highly directional nature which facilitates the formation of well-ordered structures. Herein, we review a series of research works by combining STM (scanning tunneling microscopy) with theoretical calculations, to reveal the processes used in the area of self-assembly driven by molecule Landers equipped with functional groups on the metallic surfaces. Combining these processes is necessary for researchers to advance the self-assembly of supramolecular architectures driven by multiple non-covalent interactions on solid surfaces

Structural and electronic properties of hexa-adamantyl-hexa-phenylbenzene molecules studied by low temperature scanning tunneling microscopy

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Observation and manipulation of hexa-adamantyl-hexa-benzocoronene molecules by low temperature scanning tunneling microscopy

cited By 2International audienceLarge molecules made of a central hexa-adamantyl-hexa-benzocoronene plateau surrounded by six adamantyl groups have been investigated by low temperature scanning tunneling microscopy and scanning tunneling spectroscopy coupled with image calculations and molecular mechanics. The structure of large self-assembled domains reveals that the intermolecular interactions between adamantyl peripheral groups dominate film growth. At very low coverage, the molecules can exhibit a certain instability for negative bias voltages which induces a partial rotation. Manipulations of single objects using the STM tip are used to create small clusters of two or three molecules. The formed structures can be obtained and manipulated provided that the flexible adamantyl moieties of neighbouring molecules are brought in close contact promoting a robust mechanical anchoring

UHV-STM Investigations and Numerical Calculations of a Ruthenium β-Diketonato Complex with Protected Ethynyl Ligand: [Ru(dbm) 2 (acac-TIPSA)]

International audienceThe quest of molecular electronic devices necessitates addressing model molecular systems as starting points. Among the targeted functions, electron transfer between specific moieties inside a molecule is expected to play a fundamental role for ultimate logical gates. Here we propose a coordination complex exhibiting two inorganic centers (Ru and Si) that constitutes a step towards a more complex architecture. Starting from the complex 1 [Ru(dbm)2(acac-I)] (dbm = dibenzoylmethanate ion, acac-I = 3-iodo-2,4-pentanedionate ion), the complex 2 [Ru(dbm)2(acac-TIPSA)] (acac-TIPSA=3-(triisopropylsilyl)acetylene-2,4-pentanedionate ion) was obtained through Sonogashira cross coupling reaction under classical conditions. This complex 2 was characterized by elemental analysis, IR, 1H NMR, 13C NMR, UV-Vis, cyclic voltammetry, mass spectroscopy as well as X-ray single crystal diffraction. It crystallized with empirical formula of C46H49O6Ru1Si1 in a monoclinic crystal system and space group P21/c with a = 21.077(3) Å, b = 9.5130(7) Å, c = 21.8790(12) Å, beta = 94.125(7)°, V = 4375.5(7) Å3 and Z = 4. Additionally, scanning tunneling microscopy measurements at liquid He temperature and in an ultra-high vacuum (UHV-STM) were conducted on complex 2 on a Ag(111) surface. The STM images, supported by adsorption and STM image calculations, demonstrate that the molecules exist in two stable forms when adsorbed on the metallic surface