A Tripodal [2]Rotaxane on the Surface of Gold

Nikitin, Kirill; Lestini, Elena; Lazzari, M.; Altobello, Silvano; Fitzmaurice, Donald

doi:10.1021/la701657r

Cited by 39 publications

(28 citation statements)

References 31 publications

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“…Tripodala nchors with three binding sites are one type of most employed molecules with multiple contact sites. Among them, the C 3 -symmetric platform tetraphenylmethane, [45][46][47] tetraphenylsilane and related structures, [48][49][50] 1,3,5,7-tetrasubstitted adamantane, [51,52] and 9,9'-spirobifluorene [53,54] have received considerable interest. Figure 1s hows the representative molecules 1-4 of these four kinds of platforms with thiol groupsa st he contact sites.…”

Section: Tripodal Anchorsmentioning

confidence: 99%

Multidentate Anchors for Surface Functionalization

Tang

Zhong

2019

Chemistry An Asian Journal

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The bottom‐up functionalization of solid surfaces shows increasing importance for a wide range of interdisciplinary applications. Multidentate anchors with more than two contact points can bind to solid surfaces with strong chemisorption, well‐defined upright configuration, and tailored functionality. The surface functionalization using multidentate anchors with three (tripodal), four (quadripodal), or more binding points is summarized herein, with a focus on those beyond classical tripodal anchors. In particular, the molecular design on how to achieve multisite interaction between anchor and substrate and the introduction of functional groups to thin films are discussed.

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Section: Tripodal Anchorsmentioning

confidence: 99%

Multidentate Anchors for Surface Functionalization

Tang

Zhong

2019

Chemistry An Asian Journal

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“…The ratio of TiO 2 NP surface area to the footprint of the tripodal linker is about 800, hence, the NP surface can be approximately treated as locally flat. [44] Nevertheless, the presence of large, separated stalks of tripodal axles on the surface would create a complex potential surface that is concave between the linkers and convex around them to match their potential. However, since our interest is mainly in the immediate vicinity of the stalks, Equation (7) for the diffuse layer can be reduced to one dimension, x, along the surface normal.…”

Section: Effect Of the Adsorption On Tio 2 Npsmentioning

confidence: 99%

“…Additionally, the large footprint of the tripodal linkers helps to prevent unwanted side-to-side interactions between the adsorbed molecules. [44] The influence of the length and type of the linker between the anchor and the electroactive unit is another important aspect of interfacial ET, often considered within the framework of donor-bridge-acceptor formalism (D-B-A). [45] Most studies on the bridge effect concerned ferrocene-or viologen-modified self-assembled monolayers on gold surfaces, [46,47] although the findings are applicable for many TiO 2 NP-based systems in which TiO 2 can be either an electron donor (e.g.…”

Section: Introductionmentioning

confidence: 99%

Electron Transfer and Switching in Rigid [2]Rotaxanes Adsorbed on TiO₂ Nanoparticles

et al. 2012

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Bistable [2]rotaxanes have been attached through a bulky tripodal linker to the surface of titanium dioxide nanoparticles and studied by cyclic voltammetry and spectroelectrochemical methods. The axle component in the [2]rotaxane contains two viologen sites, V(1) and V(2), interconnected by a rigid terphenylene bridge. In their parent dication states, V(1)(2+) and V(2)(2+) can both accommodate a crown ether ring, C, but are not equivalent in terms of their affinity towards C and have different electrochemical reduction potentials. The geometry and size of the tripodal linker help to maintain a perpendicular [2]rotaxane orientation at the surface and to avoid unwanted side-to-side interactions. When the rigid [2]rotaxane or its corresponding axle are adsorbed on a TiO(2) nanoparticle, viologen V(2)(2+) is reduced at significantly more negative potentials (-0.3 V) than in flexible analogues that contain aliphatic bridges between V(1) and V(2). These overpotentials are analysed in terms of electron-transfer rates and a donor-bridge-acceptor (D-B-A) formalism, in which D is the doubly reduced viologen, V(1)(0), adjacent to the TiO(2) surface (TiO(2)-V(1)(0)), B is the terphenylene bridge and A is viologen V(2)(2+). We have also found that, in contrast with earlier findings in solution, no molecular shuttling occurs in rigid [2]rotaxane adsorbed at the surface. The observations were explained by the relative position of the viologen stations within the electrical double layer, screening of V(2)(2+) by the counterions and high capacity of the medium, which reduces the mobility of the crown ether. The results are useful in transposing of solution-based molecular switches to the interface or in the design and understanding of the properties of systems comprising electroactive and/or interlocked molecules adsorbed at the nanostructured TiO(2) surface.

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“…In contrast to many current approaches, we aimed to separate these additional anchoring points from the conductive backbone of the molecule and avoid sp 3 ‐hybridisation in the conductive pathway. We note that while this study focuses on the molecular electronics applications of our new anchoring motif, it may also prove adaptable as a useful scaffold for other applications, for example, gold surface‐assemblies of optoelectronic materials, switches or polymerisation initiators …”

Section: Introductionmentioning

confidence: 99%

Carbazole‐Based Tetrapodal Anchor Groups for Gold Surfaces: Synthesis and Conductance Properties

et al. 2019

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As the field of molecular‐scale electronics matures and the prospect of devices incorporating molecular wires becomes more feasible, it is necessary to progress from the simple anchor groups used in fundamental conductance studies to more elaborate anchors designed with device stability in mind. This study presents a series of oligo(phenylene‐ethynylene) wires with one tetrapodal anchor and a phenyl or pyridyl head group. The new anchors are designed to bind strongly to gold surfaces without disrupting the conductance pathway of the wires. Conductive probe atomic force microscopy (cAFM) was used to determine the conductance of self‐assembled monolayers (SAMs) of the wires in Au–SAM–Pt and Au–SAM–graphene junctions, from which the conductance per molecule was derived. For tolane‐type wires, mean conductances per molecule of up to 10−4.37 G0 (Pt) and 10−3.78 G0 (graphene) were measured, despite limited electronic coupling to the Au electrode, demonstrating the potential of this approach. Computational studies of the surface binding geometry and transport properties rationalise and support the experimental results.

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A Tripodal [2]Rotaxane on the Surface of Gold

Cited by 39 publications

References 31 publications

Multidentate Anchors for Surface Functionalization

Multidentate Anchors for Surface Functionalization

Electron Transfer and Switching in Rigid [2]Rotaxanes Adsorbed on TiO₂ Nanoparticles

Carbazole‐Based Tetrapodal Anchor Groups for Gold Surfaces: Synthesis and Conductance Properties

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A Tripodal [2]Rotaxane on the Surface of Gold

Cited by 39 publications

References 31 publications

Multidentate Anchors for Surface Functionalization

Multidentate Anchors for Surface Functionalization

Electron Transfer and Switching in Rigid [2]Rotaxanes Adsorbed on TiO2 Nanoparticles

Carbazole‐Based Tetrapodal Anchor Groups for Gold Surfaces: Synthesis and Conductance Properties

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Electron Transfer and Switching in Rigid [2]Rotaxanes Adsorbed on TiO₂ Nanoparticles