Conductance Switching in Single Molecules Through Conformational Changes

Donhauser, Zachary J.; Mantooth, Brent A.; Kelly, Kevin F.; Bumm, Lloyd A.; Monnell, Jason D.; Stapleton, Joshua J.; Price, David W.; Rawlett, Adam M.; Allara, David L.; Tour, James M.; Weiss, Paul S.

doi:10.1126/science.1060294

Cited by 1,218 publications

(1,163 citation statements)

References 25 publications

Supporting

Mentioning

1,134

Contrasting

Unclassified

Order By: Relevance

“…The difference in height enables the identification of the two molecular species at various stages of their exchange reaction. 27,43 Figure 1 details a morphological comparison of single-component C10 and C12Se SAMs on Au{111}.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Exchange Reactions between Alkanethiolates and Alkaneselenols on Au{111}

et al. 2014

View full text Add to dashboard Cite

When alkanethiolate self-assembled monolayers on Au{111} are exchanged with alkaneselenols from solution, replacement of thiolates by selenols is rapid and complete, and is well described by perimeter-dependent island growth kinetics. The monolayer structures change as selenolate coverage increases, from being epitaxial and consistent with the initial thiolate structure to being characteristic of selenolate monolayer structures. At room temperature and at positive sample bias in scanning tunneling microscopy, the selenolate–gold attachment is labile, and molecules exchange positions with neighboring thiolates. The scanning tunneling microscope probe can be used to induce these place-exchange reactions.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 99%

Exchange Reactions between Alkanethiolates and Alkaneselenols on Au{111}

et al. 2014

View full text Add to dashboard Cite

show abstract

“…[1][2][3][4][5][6][7][8] . A comprehensive analysis of the properties of these systems could be very useful for designing highly biocompatible materials and specific biosensors [9][10][11][12][13][14] .…”

Section: Introductionmentioning

confidence: 99%

Dispersion corrected DFT approaches for anharmonic vibrational frequency calculations: nucleobases and their dimers

Fornaro

Biczysko

Monti

et al. 2014

Phys. Chem. Chem. Phys.

101

113

View full text Add to dashboard Cite

Computational spectroscopy techniques have become in the last years effective means to analyze and assign infrared (IR) spectra for molecular systems of increasing dimensions and in different environments. However, transition from compilations of harmonic data to full anharmonic simulations of spectra is still under way. The most promising results for large systems have been obtained, in our opinion, by perturbative vibrational approaches based on potential energy surfaces computed by hybrid (especially B3LYP) density functionals and medium size (e.g. SNSD) basis sets. In this framework, we are actively developing a comprehensive and robust computational protocol aimed to a quantitative reproduction of the spectra of nucleic acid bases complexes and their adsorption on solid supports (organic/inorganic). In this contribution we report the essential results of the first step devoted to isolated monomers and dimers. It is well known that in order to model the vibrational spectra of weakly bound molecular complexes dispersion interactions should be taken into proper account. In this work, we have chosen two popular and inexpensive approaches to model dispersion interaction, namely the semi-empirical dispersion correction (D3) and pseudopotential based (DCP) methodologies both in conjunction with the B3LYP functional. These have been used for simulating fully anharmonic IR spectra of nucleobases and their dimers through generalized second order vibrational perturbation theory (GVPT2). We have studied, in particular, isolated adenine, hypoxanthine, uracil, thymine and cytosine, the hydrogen-bonded and stacked adenine and uracil dimers, and the stacked adenine-naphthalene heterodimer. Anharmonic frequencies are compared with standard B3LYP results and experimental findings, while the computed interaction energies and structures of complexes are compared to the best available theoretical estimates.

show abstract

“…A number of studies have found that for saturated chains on Au β ≈ 1.0 ± 0.1 Å −1 , 55−63 whereas for phenylene ethynylene molecules, with mixed sp and sp 2 hybridization, it is approximately a factor of 2 lower and β ≈ 0.57 ± 0.02 Å −1 . 64,65 Note that phenylene vinylene and other all sp 2 -hybridized systems have β values another factor of two lower 66 and thus are more conductive (and would be expected to quench even faster than the tether in Azo2).…”

Section: Sectionmentioning

confidence: 99%

Effect of Tether Conductivity on the Efficiency of Photoisomerization of Azobenzene-Functionalized Molecules on Au{111}

Pathem

Yong

Payton

et al. 2012

J. Phys. Chem. Lett.

View full text Add to dashboard Cite

ABSTRACT:We establish the role of tether conductivity on the photoisomerization of azobenzene-functionalized molecules assembled as isolated single molecules in well-defined decanethiolate self-assembled monolayer matrices on Au{111}. We designed the molecules so as to tune the conductivity of the tethers that separate the functional moiety from the underlying Au substrate. By employing surface-enhanced Raman spectroscopy, time-course measurements of surfaces assembled with azobenzene functionalized with different tether conductivities were independently studied under constant UV light illumination. The decay constants from the analyses reveal that photoisomerization on the Au{111} surface is reduced when the conductivity of the tether is increased. Experimental results are compared with density functional theory calculations performed on single molecules attached to Au clusters. SECTION:Physical Processes in Nanomaterials and Nanostructures P recise control over the reversible isomerization of functional molecules when assembled on solid surfaces is of great importance to understand the rules of molecular-and supramolecular-scale action. 1−14 Various kinds of photochromic molecules such as azobenzene, 15−24 diarylethene, 9,25−27 spiropyran, 28−30 and more recently dihydroazulene 31−34 have been investigated as possible candidates for molecular switches. These families of functional molecules have relative advantages and disadvantages due to factors such as their ease of molecular assembly on substrates, quantum yield of photoisomerization, reversibility of isomerization, and quenching of isomerization by the underlying substrate. Of these families of photochromic molecules, azobenzenes have thus far attracted the greatest attention.Azobenzene (henceforth Azo) exists in a near-planar trans conformation in its thermodynamically stable state with nearly zero dipole moment. 35,36 When irradiated with UV light at ∼365 nm, the molecule isomerizes to a nonplanar cis conformation via rotation of a phenyl group out of the plane of the azobenzene moiety, carrying a dipole moment of 3 D. 36 Upon subsequent irradiation with ∼420 nm visible light, the cis conformation reverts back to its original trans conformation, although thermal relaxation from cis to trans has also been shown to be a common pathway for the reverse reaction where relaxation times typically depend on the substituents on the azobenzene moiety ranging from minutes (for alkyl-substituted molecules) to days (for unsubstituted azobenzenes). Because of their difference in planarity, it has been established that trans form is approximately 100 times more conductive than cis, 16 and hence azobenzenes are considered to be a type of molecular switches. 22 Various theoretical and experimental studies have been performed to understand the mechanisms of photoisomerization of azobenezenes in the gas phase, in various solvents, and on solid substrates when isolated as single molecules or in ensembles. For instance, it has been wellestablished that photoisomerization of...

show abstract

Conductance Switching in Single Molecules Through Conformational Changes

Cited by 1,218 publications

References 25 publications

Exchange Reactions between Alkanethiolates and Alkaneselenols on Au{111}

Exchange Reactions between Alkanethiolates and Alkaneselenols on Au{111}

Dispersion corrected DFT approaches for anharmonic vibrational frequency calculations: nucleobases and their dimers

Effect of Tether Conductivity on the Efficiency of Photoisomerization of Azobenzene-Functionalized Molecules on Au{111}

Contact Info

Product

Resources

About