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

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

Synthesis and Characterization of a Series of Ruthenium Tris(β-diketonato) Complexes by an UHV-STM Investigation and Numerical Calculations

International audienceA series of ruthenium tris(beta-diketonate), was investigated using electrochemistry, UV-Vis spectroscopy, 1H and 13C NMR and FAB mass spectroscopy. Several new mononuclear mixed-ligand ruthenium(III) complexes including - dibenzoylmethanate ion (dbm); [Ru(dbm)3] 1 - one or two acetylacetonate ion (2,4-pentanedionate, acac-); [Ru(dbm)2(acac)] 2, [Ru(dbm)(acac)2] 3 - acetonitrile ligand; [Ru(dbm)2(CH3CN)2][CF3SO3] 4 - or functionalized acetylacetonate ion; [Ru(dbm)2(acac-I)] 5 (acac-I = 3-iodo-2,4-pentanedionate ion), [Ru(dbm)2(acac-Br)] 6 (acac-Br = 3-bromo-2,4-pentanedionate ion) were prepared. In addition, X-Ray structures for complexes 1, 2, 3, 4 and 6 were determined. Scanning tunneling microscopy measurement at liquid He temperature and in ultra high vacuum (UHV-STM) of complex 1 on Ag(111) surface was conducted. This indicates that the complex can be successfully evaporated and observed after adsorption on a metallic substrate. Analysis of the STM images, supported by adsorption and STM image calculations demonstrates that the molecules exist in two stable forms when adsorbed on the surface

Bicomponent hydrogen-bonded nanostructures formed by two complementary molecular Landers on Au(111)

International audienceThe co-adsorption of two molecular Landers equipped with functional groups capable of forming a complementary triple hydrogen-bonding motif is investigated with scanning tunneling microscopy and molecular mechanics calculations. Surprisingly, the anticipated complementary motif is not realised in 2-D terrace structures, but is observed in 1-D structures at step edges where molecular conformational flexibility is confined

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

The 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 toward a more complex architecture. Starting from the complex <b>1</b> [Ru­(dbm)₂(acac-I)] (dbm = dibenzoylmethanate ion, acac-<i>I</i> = 3-iodo-2,4-pentanedionate ion), the complex <b>2</b> [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 <b>2</b> 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 <i>P</i>2₁/<i>c</i> with <i>a</i> = 21.077(3) Å, <i>b</i> = 9.5130(7) Å, <i>c</i> = 21.8790(12) Å, β = 94.125(7)°, <i>V</i> = 4375.5(7) ų and <i>Z</i> = 4. Additionally, scanning tunneling microscopy measurements at liquid He temperature and in an ultrahigh vacuum (UHV-STM) were conducted on complex <b>2</b> 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

Three-dimensional hydrogen bonding between Landers and planar molecules facilitated by electrostatic interactions with Ni adatoms

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