scholarly journals Thiocyanate Anchors for Salt-like Iron(II) Complexes on Au(111): Promises and Caveats

2014 ◽  
Vol 69 (11-12) ◽  
pp. 1164-1180 ◽  
Author(s):  
Philipp Stock ◽  
Andreas Erbe ◽  
Manfred Buck ◽  
Dennis Wiedemann ◽  
Hervé Ménard ◽  
...  
Keyword(s):  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Sulphur Atom ◽  
X Ray ◽  
New Class ◽  
Scanning Tunnelling ◽  
Assembled Monolayers ◽  
Tunnelling Microscopy ◽  
Self Assembled ◽  
Ionic Iron

Abstract The formation of self-assembled monolayers (SAMs) on Au(111) from solution has been investigated for two ionic iron(II) complexes of the type [Fe(L)](BF4)2, where L is tripodal hexadentate and contains three thiocyanate anchor groups. The ligands (L1, L2; donor set: N6) are obtained by Schiff base condensation of a tripodal triamine (L1: tris-(2-aminoethyl)amine, ‘tren’; L2: 1,1′,1″- trimethyl(thiophosphoryl)trihydrazide) with 5-(4-thiocyanatobutoxy) pyridine-2-carbaldehyde. Layers of the complexes adsorbed on Au(111) from methanol solution have been characterised using scanning tunnelling microscopy (STM), infrared reflectance absorbance (IRRAS), X-ray photoelectron (XPS) and UV=Vis reflectance spectroscopies, as well as ellipsometry. Complex [Fe(L1)](BF4)2 deposits intact on a gold surface and retains its optical addressability. Elaboration of this result may provide access to a new class of self-assembled layers, employing salt-like tripodal coordination compounds with thiocyanate anchors. The second complex, [Fe(L2)](BF4)2, which contains a sulphur atom in the ligand backbone, is not sufficiently stable under the same conditions.

scholarly journals STM visualisation of counterions and the effect of charges on self-assembled monolayers of macrocycles

2011 ◽  
Vol 2 ◽  
pp. 674-680 ◽  
Author(s):  
Tibor Kudernac ◽  
Natalia Shabelina ◽  
Wael Mamdouh ◽  
Sigurd Höger ◽  
Steven De Feyter
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Self Assembled Monolayers ◽  
Assembly Process ◽  
Organic Monolayers ◽  
Preferential Adsorption ◽  
Scanning Tunnelling ◽  
Assembled Monolayers ◽  
Tunnelling Microscopy ◽  
Self Assembled

Despite their importance in self-assembly processes, the influence of charged counterions on the geometry of self-assembled organic monolayers and their direct localisation within the monolayers has been given little attention. Recently, various examples of self-assembled monolayers composed of charged molecules on surfaces have been reported, but no effort has been made to prove the presence of counterions within the monolayer. Here we show that visualisation and exact localisation of counterions within self-assembled monolayers can be achieved with scanning tunnelling microscopy (STM). The presence of charges on the studied shape-persistent macrocycles is shown to have a profound effect on the self-assembly process at the liquid–solid interface. Furthermore, preferential adsorption was observed for the uncharged analogue of the macrocycle on a surface.

Scanning tunnelling microscopy investigations of self-assembled monolayers of poly(3-decyl-thiophene) on graphite

1993 ◽  
Vol 2 (6) ◽  
pp. 295-299 ◽  
Author(s):  
Annalisa Bonfiglio ◽  
Rita Paradiso ◽  
Ermanno Di Zitti ◽  
Davide Ricci ◽  
Alberto Bolognesi ◽  
...  
Keyword(s):  
Scanning Tunnelling Microscopy ◽  
Self Assembled Monolayers ◽  
Scanning Tunnelling ◽  
Assembled Monolayers ◽  
Tunnelling Microscopy ◽  
Self Assembled

Self-Assembled Monolayers of Heme Derivatives on a Gold Surface

2000 ◽  
Vol 73 (9) ◽  
pp. 1993-2000 ◽  
Author(s):  
Kazutoshi Kobayashi ◽  
Shin'ichiro Imabayashi ◽  
Katsuhiko Fujita ◽  
Kazuhide Nonaka ◽  
Takashi Kakiuchi ◽  
...  
Keyword(s):  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Assembled Monolayers ◽  
Self Assembled

Spectral and cyclic voltammetric characterization of self-assembled monolayers on gold of pyrene end-labeled oligonucleotide duplexes

1999 ◽  
Vol 77 (5-6) ◽  
pp. 1077-1084 ◽  
Author(s):  
R Scott Reese ◽  
Marye Anne Fox
Keyword(s):  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Self Assembled Monolayer ◽  
Surface Emission ◽  
Assembled Monolayers ◽  
Oligonucleotide Duplex ◽  
Self Assembled ◽  
Duplex Formation

Self-assembled monolayers of sulfur-terminated oligonucleotide duplexes were formed on flat gold surfaces, either by exposure of a self-assembled monolayer bearing one oligonucleotide strand to the complementary strand or by preformation of a oligonucleotide duplex that was then deposited on a fresh gold surface. Virtually identical spectral behavior was observed whether the duplex was produced before deposition or by in situ complementary association. With a duplex bearing an appropriate pyrene end-label, the resulting thin film was photoresponsive. Surface emission measurements show no evidence for pyrene aggregation on the modified surfaces. The polarity of the photocurrent, reflecting photoinduced electron transfer initiated by photoexcitation of pyrene, is opposite that expected from the oligonucleotide-mediated reduction of the appended pyrene excited state.Key words: oligonucleotide, self-assembled monolayer, duplex formation, photoelectrochemistry, surface emission.

scholarly journals X-ray spectroscopy characterization of self-assembled monolayers of nitrile-substituted oligo(phenylene ethynylene)s with variable chain length

2012 ◽  
Vol 3 ◽  
pp. 12-24 ◽  
Author(s):  
Hicham Hamoudi ◽  
Ping Kao ◽  
Alexei Nefedov ◽  
David L Allara ◽  
Michael Zharnikov
Keyword(s):  
Chain Length ◽  
Photoelectron Spectroscopy ◽  
Self Assembled Monolayers ◽  
Phenylene Ethynylene ◽  
X Ray ◽  
Molecular Length ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Gold Thiolate

Self-assembled monolayers (SAMs) of nitrile-substituted oligo(phenylene ethynylene) thiols (NC-OPEn) with a variable chain length n (n ranging from one to three structural units) on Au(111) were studied by synchrotron-based high-resolution X-ray photoelectron spectroscopy and near-edge absorption fine-structure spectroscopy. The experimental data suggest that the NC-OPEn molecules form well-defined SAMs on Au(111), with all the molecules bound to the substrate through the gold–thiolate anchor and the nitrile tail groups located at the SAM–ambient interface. The packing density in these SAMs was found to be close to that of alkanethiolate monolayers on Au(111), independent of the chain length. Similar behavior was found for the molecular inclination, with an average tilt angle of ~33–36° for all the target systems. In contrast, the average twist of the OPEn backbone (planar conformation) was found to depend on the molecular length, being close to 45° for the films comprising the short OPE chains and ~53.5° for the long chains. Analysis of the data suggests that the attachment of the nitrile moiety, which served as a spectroscopic marker group, to the OPEn backbone did not significantly affect the molecular orientation in the SAMs.

scholarly journals Density Functional Theory with Modified Dispersion Correction for Metals Applied to Self-Assembled Monolayers of Thiols on Au(111)

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
M. P. Andersson
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Dimethyl Disulfide ◽  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Dispersion Correction ◽  
Dissociative Chemisorption ◽  
Functional Theory ◽  
Assembled Monolayers ◽  
Self Assembled

Using sound physical principles we modify the DFT-D2 atom pairwise semiempirical dispersion correction to density functional theory to work for metallic systems and in particular self-assembled monolayers of thiols on gold surfaces. We test our approximation for two functionals PBE-D and revPBE-D for lattice parameters and cohesive energies for Ni, Pd, Pt, Cu, Ag, and Au, adsorption energies of CO on (111) surfaces of Pd, Pt, Cu, Ag, and Au, and adsorption energy of benzene on Ag(111) and Au(111). Agreement with experimental data is substantially improved. We apply the method to self-assembled monolayers of alkanethiols on Au(111) and find reasonable agreement for PBE-D and revPBE-D for both physisorption of n-alkanethiols as well as dissociative chemisorption of dimethyl disulfide as an Au-adatom-dithiolate complex. By modifying the C6 coefficient for Au, we obtain quantitative agreement for physisorption and chemisorption for both PBE-D and revPBE-D using the same set of parameters. Our results confirm that inclusion of dispersion forces is crucial for any quantitative analysis of the thiol and thiolate bonds to the gold surface using quantum chemical calculations.

Self-Assembled Monolayers of Hexapeptides on Gold:  Surface Characterization and Orientation Distribution Analysis†

2004 ◽  
Vol 108 (45) ◽  
pp. 9673-9681 ◽  
Author(s):  
Xingu Wen ◽  
Richard W. Linton ◽  
Fernando Formaggio ◽  
Claudio Toniolo ◽  
Edward T. Samulski
Keyword(s):  
Surface Characterization ◽  
Gold Surface ◽  
Orientation Distribution ◽  
Self Assembled Monolayers ◽  
Distribution Analysis ◽  
Assembled Monolayers ◽  
Self Assembled

scholarly journals Sub-100-nm Pattern Formation through Selective Chemical Transformation of Self-Assembled Monolayers by Soft X-ray Irradiation

Langmuir ◽  
2004 ◽  
Vol 20 (16) ◽  
pp. 6964-6964 ◽  
Author(s):  
Young-Hye La ◽  
Yu Jin Jung ◽  
Hyun Ju Kim ◽  
Tai-Hee Kang ◽  
Kyuwook Ihm ◽  
...  
Keyword(s):  
Pattern Formation ◽  
Chemical Transformation ◽  
Self Assembled Monolayers ◽  
X Ray ◽  
Assembled Monolayers ◽  
Selective Chemical ◽  
Self Assembled
Sign in / Sign up

Export Citation Format

Share Document