Molecular Switches Flipped by Oxygen

Zehm, Daniel; Fudickar, Werner; Linker, Torsten

doi:10.1002/anie.200700443

Cited by 81 publications

(58 citation statements)

References 55 publications

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“…in 13 C NMR analysis (Supplementary Fig. S9a)2021. The 9,10-endoperoxide was also formed by 4 under the same experimental conditions (Supplementary Fig.…”

Section: Resultsmentioning

confidence: 73%

“…3a) peaks of the anthracene chromophore of 4 in solution had completely disappeared after just 2 h (Supplementary Figs S5 and S6). This could be attributed to conversion of the anthracene unit into 9,10-endoperoxides upon irradiation20. The 1 H resonance characteristics of the parent anthracene protons exhibited significant changes upon irradiation (Supplementary Fig.…”

Section: Resultsmentioning

confidence: 97%

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Nonvolatile liquid anthracenes for facile full-colour luminescence tuning at single blue-light excitation

et al. 2013

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Nonvolatile room-temperature luminescent molecular liquids are a new generation of organic soft materials. They possess high stability, versatile optical properties, solvent-free fluid behaviour and can effectively accommodate dopant dye molecules. Here we introduce an approach to optimize anthracene-based liquid materials, focussing on enhanced stability, fluorescence quantum yield, colour tunability and processability, with a view to flexible electronic applications. Enveloping the anthracene core in low-viscosity branched aliphatic chains results in stable, nonvolatile, emissive liquid materials. Up to 96% efficient energy-transfer-assisted tunable emission is achieved by doping a minute amount of acceptor dye in the solvent-free state. Furthermore, we use a thermoresponsive dopant to impart thermally controllable luminescence colours. The introduced strategy leading to diverse luminescence colours at a single blue-light excitation can be an innovative replacement for currently used luminescent materials, providing useful continuous emissive layers in developing foldable devices.

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“…in 13 C NMR analysis (Supplementary Fig. S9a)2021. The 9,10-endoperoxide was also formed by 4 under the same experimental conditions (Supplementary Fig.…”

Section: Resultsmentioning

confidence: 73%

Section: Resultsmentioning

confidence: 97%

Nonvolatile liquid anthracenes for facile full-colour luminescence tuning at single blue-light excitation

et al. 2013

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“…Zehm, Fudickar, and Linker [41] set up molecular rotary switches of bisarylanthracenes flipped by covalent binding [42], then release of oxygen (Fig. 8b,c).…”

Section: Molecular Switchesmentioning

confidence: 99%

Synthetic Molecular Machines and Polymer/Monomer Size Switches that Operate Through Dynamic and Non-Dynamic Covalent Changes

Stadler

Ramírez

2011

Constitutional Dynamic Chemistry

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The present chapter is focused on how synthetic molecular machines (e.g. shuttles, switches and molecular motors) and size switches (conversions between polymers and their units, i.e., conversions between relatively large and small molecules) can function through covalent changes. Amongst the interesting examples of devices herein presented are molecular motors and size switches based on dynamic covalent chemistry which is an area of constitutional dynamic chemistry.

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“…[ 7 ] The predominant mechanism for this molecule involves activation of O 2 molecules by the initially-formed excited state; this either generates singlet O 2 species or a superoxide O 2 − which then adds back across appropriate carbon centres in TIPS-pentacene to produce an endoperoxide (EPO), which is seen as the main product by NMR. [ 7 ] Recent studies using chemically generated [ 8,9 ] singlet O 2 have further demonstrated that the superoxide route is the most favoured of the two for TIPS-pentacene, contributing around 90% to the overall rate of EPO formation. Electron transfer rates from excited-state pentacenes are also observed to be fast and solvent-dependent.…”

Section: Concentration-and Solvent-dependent Photochemical Instabilitmentioning

confidence: 99%

Concentration‐ and Solvent‐Dependent Photochemical Instability of 6,13‐Bis(triisopropysilylethynyl)pentacene

Abu-Sen

Morrison

Horn

et al. 2014

Advanced Optical Materials

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lifetimes are also strongly environment-dependent, ranging from around 7 ns in dilute solution [ 17 ] to sub-ps in thin fi lms. [ 15 ] Direct observation of the kinetics of singlet fi ssion of TIPSpentacene in anhydrous, O 2 -free CHCl 3 solution over a range of concentrations reveals a singlet lifetime of ∼13 ns, [ 18 ] whilst a high-concentration triplet yield of 200% and triplet formation at a rate approaching the diffusion limit indicates the effi ciency of the process. Physical quenching must also be considered as a deactivation route in any condensed medium. Stability in solution is therefore controlled by the rates and quantum yields of these processes, many of which are not known. Recent reports of half-life increase by the attachment of stable radical species to pentacenes is further evidence of the importance of the initial singlet state lifetime. [ 19 ] In this communication, a systematic study of the half-life of TIPS-pentacene in a variety of air-equilibrated common solvents (including toluene, tetrahydrofuran (THF), dichloromethane, chloroform, isopropanol (IPA), decane and dodecane) by UVvisible spectroscopy at concentrations ranging from 2.5 × 10 −6 M to 2 × 10 −2 M is reported. Correlation of the variation of halflife for TIPS-pentacene photoxidation with TIPS-pentacene concentration, solubility parameters, dissolved O 2 concentrations and intermolecular distances yields important new insight into the processes involved. In particular, a non-linear concentration dependence is observed which points to a further perturbation in solution due to the onset of aggregation.UV-visible spectra for TIPS-pentacene in toluene over a range of concentrations from 270-800 nm in a 10 mm pathlength cuvette are characterized by three long-wavelength bands at 643, 592, and 549 nm ( Figure 1 a). These spectral features correspond to the known HOMO-LUMO gap with its associated vibrational structure. [ 20,21 ] The λ max values of the longest wavelength absorption do not appear to vary with concentration over the range shown but are observed to vary slightly with solvent (Supporting Information, S4.1). Upon photodegradation, these longer wavelength bands decrease with exposure whilst new features grow in below 450 nm. Mass spectra and NMR spectra confi rm that the main product is the 6,13-endoperoxide of TIPS-pentacene (Supporting Information, S1); this shows no features in the visible absorption spectra because the conjugated π-system in the product is too short (comprising 2 naphthalene rings). The new features observed below 450 nm are due to small quantities of the 5,14-endoperoxide (effectively a substituted anthracene. [ 6 ] For each sample, plots of normalized A/A 0 at 643 nm versus time were made as shown in Figure 1 b. These absorbance-time profi les were found to be reproducible to +/-5%, with all formulations showing retardation in rate beyond t 1/2 . Comparable decays were also measured in THF, dichloromethane, IPA, chloroform, dodecane and decane over the same concentration range (Supporting Information, ...

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Molecular Switches Flipped by Oxygen

Cited by 81 publications

References 55 publications

Nonvolatile liquid anthracenes for facile full-colour luminescence tuning at single blue-light excitation

Nonvolatile liquid anthracenes for facile full-colour luminescence tuning at single blue-light excitation

Synthetic Molecular Machines and Polymer/Monomer Size Switches that Operate Through Dynamic and Non-Dynamic Covalent Changes

Concentration‐ and Solvent‐Dependent Photochemical Instability of 6,13‐Bis(triisopropysilylethynyl)pentacene

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