Coordination‐Based Molecular Assemblies of Oligofurans and Oligothiophenes

Barak, Adva Hayoun; Ruiter, Graham de; Lahav, Michal; Sharma, Sagar; Gidron, Ori; Evmenenko, Guennadi; Dutta, Pulak; Bendikov, Michael; Boom, Milko E. van der

doi:10.1002/chem.201300034

Cited by 20 publications

(7 citation statements)

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“…The effects of both the UV irradiation and the electrolyte concentration indicate that ET through the conjugated backbone of BPEB is of minor importance. This observation is expected and is in agreement with reported experimental and theoretical studies that rule out a significant conjugation between the conjugated popypyridyl-based components, coordinated through PdCl 2 . The differences in the electrochemical properties of the assemblies before and after UV irradiation (as shown in Figure ) are not because of variations of their composition, thickness, and roughness, as confirmed by spectroscopic ellipsometry, atomic force microscopy (AFM), synchrotron X-ray reflectivity (XRR), and X-ray photoelectron spectroscopy (XPS).…”

Section: Resultssupporting

confidence: 90%

“…In-depth profiling of the assemblies before and after UV irradiation confirms that the relative positions of the redox-active components are not affected by the photochemical reaction. As expected, the conjugation of the interlayer spacers plays a relatively minor role in the ET properties; rather, the distance between the redox-active layers and their permeability play a major role. Increasing the permeability results in a higher charge carrier density, which, in turn, results in increased electrochemical reversibility of the Os- and Ru-based redox processes.…”

Section: Discussionsupporting

confidence: 75%

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Light-Induced Conversion of Chemical Permeability to Enhance Electron and Molecular Transfer in Nanoscale Assemblies

et al. 2016

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In this paper, we demonstrate how photochemically enhancing the permeability of metal-organic assemblies results in a significant enhancement of the electrochemical activity of metal complexes located within the assembly. The molecular assemblies consist of different layers of redox-active metal complexes ([M(mbpy-py)][PF]; M = Ru or Os) that are separated by redox-inactive spacers consisting of 1,4-bis[2-(4-pyridyl)ethenyl]benzene (BPEB) and PdCl of variable thicknesses (0-13.4 nm). UV-irradiation (λ = 254 nm) of our assemblies induces a photochemical reaction in the redox-inactive spacer increasing the permeability of the assembly. The observed increase was evident by trapping organic (BuNBF) and inorganic (NiCl) salts inside the assemblies, and by evaluating the electrochemical response of quinones absorbed inside the molecular assemblies before and after UV irradiation. The increase in permeability is reflected by higher currents and a change in the directionality of electron transfer, i.e., from mono- to bidirectional, between the redox-active metal complexes and the electrode surface. The supramolecular structure of the assemblies dominates the overall electron transfer properties and overrules possible electron transfer mediated by the extensive π-conjugation of its individual organic components.

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Section: Resultssupporting

confidence: 90%

Section: Discussionsupporting

confidence: 75%

Light-Induced Conversion of Chemical Permeability to Enhance Electron and Molecular Transfer in Nanoscale Assemblies

et al. 2016

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“…In particular, these oligofurans are of special interest because they exhibit properties similar to those of oligothiophenes . We compared the molecular properties of assemblies MA- 4 and MA- 5 , which were constructed with derivatives of terthiophene and terfuran ( 4 and 5 ) . The electrochemical investigation reveals some cooperative effects in MA- 4 and MA- 5 , where thickness-dependent oxidation processes were observed.…”

Section: Self-assembly Of Organic Compounds On Surfacesmentioning

confidence: 99%

“…So far, we discussed organic chromophores ( 1 – 5 ) with two pyridine moieties. ,,,, The ability to form extended networks, upon increasing the number of pyridine moieties, has been explored as well. , Stang et al showed that molecular rectangles on Au surfaces can be formed having a long-range order with a virtually defect-free topology . These rectangles exhibit an in-plane orientation with respect to the Au surface.…”

Section: Self-assembly Of Organic Compounds On Surfacesmentioning

confidence: 99%

Pyridine Coordination Chemistry for Molecular Assemblies on Surfaces

2014

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CONSPECTUS: Since the first description of coordination complexes, many types of metal-ligand interactions have creatively been used in the chemical sciences. The rich coordination chemistry of pyridine-type ligands has contributed significantly to the incorporation of diverse metal ions into functional materials. Here we discuss molecular assemblies (MAs) formed with a variety of pyridine-type compounds and a metal containing cross-linker (e.g., PdCl2(PhCN2)). These MAs are formed using Layer-by-Layer (LbL) deposition from solution that allows for precise fitting of the assembly properties through molecular programming. The position of each component can be controlled by altering the assembly sequence, while the degree of intermolecular interactions can be varied by the level of π-conjugation and the availability of metal coordination sites. By setting the structural parameters (e.g., bond angles, number of coordination sites, geometry) of the ligand, control over MA structure was achieved, resulting in surface-confined metal-organic networks and oligomers. Unlike MAs that are constructed with organic ligands, MAs with polypyridyl complexes of ruthenium, osmium, and cobalt are active participants in their own formation and amplify the growth of the incoming molecular layer. Such a self-propagating behavior for molecular systems is rare, and the mechanism of their formation will be discussed. These exponentially growing MAs are capable of storing metal salts that can be used during the buildup of additional molecular layers. Various parameters influencing the film growth mechanism will be presented, including (i) the number of binding sites and geometry of the organic ligands, (ii) the metal and the structure of the polypyridyl complexes, (iii) the influence of the metal cross-linker (e.g., second or third row transition metals), and (iv) the deposition conditions. By systematic variation of these parameters, switching between linear and exponential growth could be demonstrated for MAs containing structurally well-defined polypyridyl complexes. The porosity of the MAs has been estimated by using electrochemically active probes. Incorporating multiple polypyridyl complexes of osmium and ruthenium into a single assembly give rise to composite materials that exhibit interesting electrochemical and electrochromic properties. These functional composites are especially attractive as they exhibit properties that neither of each metal complex possesses individually. Some of our MAs have very high coloration efficiencies, redox stability, fast responsive times and operate at voltages < 1.5 V. Moreover, their electrochemical properties are dependent on the deposition sequence of the polypyridyl complexes, resulting in MAs that possesses distinctive electron transfer pathways. Finally, some of these MAs are described in terms of their practical applications in electrochromic materials, storage-release chemistry, solar cells, and electron transport properties.

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“…49 Diese Beobachtung in Kombination mit einem großen An/Aus‐Verhältnis und einer niedrigen Schwellenspannung in OFETs auf Oligofuranbasis bildet einen Ausgangspunkt für zukünftige Entwicklungen von OLETs 48. 51, 52 Zu diesem Zweck untersuchte die Gruppe von Tanigaki vor kurzem die durch Biphenylreste abgeschlossenen Furanoligomere BPFF und BPFT (Tabelle 2). 53 Einkristall‐FET‐Bauelemente aus sowohl BPFF als auch BPFT wiesen eine gute Lochmobilität auf (Tabelle 2), während sich das BPFT‐Bauelement durch eine gute Elektronenmobilität und Elektrolumineszenz auszeichnete.…”

Section: Elektronische Und Optoelektronische Bauelemente Auf Oligounclassified

α‐Oligofurane: eine aufstrebende Klasse konjugierter Oligomere für die organische Elektronik

Gidron

Bendikov

2014

Angewandte Chemie

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Obwohl sich der Bereich der organischen Elektronik im Laufe der letzten Jahre erheblich weiterentwickelt hat, wird er noch immer durch die Zahl verfügbarer Materialien beschränkt. Ein weiterer Ausbau erfordert die Einführung neuartiger π‐konjugierter Rückgrate, geeignete Kandidaten hierfür werden aber nur sehr selten entdeckt. Die Einführung einer neuen Klasse konjugierter Materialien – der langen α‐Oligofurane – wurde daher vor kurzem mit großem Interesse begrüßt. α‐Oligofurane weisen viele Eigenschaften auf, die für Anwendungen in organischen elektronischen Materialien erforderlich sind, und sollen biologisch abbaubar sein. Dieser Kurzaufsatz bietet eine Beschreibung langer Oligofurane aus der Perspektive ihrer Synthese, molekularen Eigenschaften, chemischen Reaktivität und Verwendung in elektronischen Bauelementen.

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Coordination‐Based Molecular Assemblies of Oligofurans and Oligothiophenes

Cited by 20 publications

References 116 publications

Light-Induced Conversion of Chemical Permeability to Enhance Electron and Molecular Transfer in Nanoscale Assemblies

Light-Induced Conversion of Chemical Permeability to Enhance Electron and Molecular Transfer in Nanoscale Assemblies

Pyridine Coordination Chemistry for Molecular Assemblies on Surfaces

α‐Oligofurane: eine aufstrebende Klasse konjugierter Oligomere für die organische Elektronik

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