Functionalized photochromics for molecular switching: the multistabilities of a dihydroazulene–anthraquinone system

Achatz, J.; Fischer, Christian; Salbeck, Josef; Daub, Jörg

doi:10.1039/c39910000504

Cited by 55 publications

(17 citation statements)

References 12 publications

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“…In fact, these compounds were also included in the investigation, but it rapidly became clear that the switching process could not be observed or did not take place. When we found, however, that rapid switching occurred upon protonation of the DMA residue, we had discovered a new three-way chromophoric molecular switch (for a report on a three-way switch consisting of a DHA group and an acid-sensitive, redox-active anthraquinone moiety, see [29]). The three addressable sub-units in 11, capable of undergoing individual, reversible switching cycles are i) the TEE core, which can be reversibly photoisomerized between its cis-and trans-forms, ii) the DHA unit, which can be transformed into a VHF moiety upon irradiation, and iii) the proton-sensitive DMA group.…”

Section: Scheme 8 Synthesis Of Cis-11amentioning

confidence: 99%

Photoswitchable Tetraethynylethene-Dihydroazulene Chromophores

Gobbi¹,

Seiler²,

Diederich³

et al. 2001

HCA

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The synthesis, characterization, and photophysical as well as electrochemical properties of the photochromic hybrid systems 11 ± 16 and 18, which contain photoswitchable tetraethynylethene (TEE; 3,4-diethynylhex-3-ene-1,5-diyne) and dihydroazulene (DHA) moieties, are presented. The molecular photoswitches were synthesized by a Sonogashira cross-coupling reaction between an appropriate TEE precursor (6 ± 10 and 17) and an iodinated DHA 1 or its vinylheptafulvene (VHF) isomer (4) (Schemes 5 ± 7). X-Ray crystal structures of five DHA derivatives (1, trans-11a, cis-11a, 12, and 13) are discussed (Figs. 2 ± 5). In all compounds, the cyclohexatriene moiety of the DHA chromophore adopts a clear boat conformation (Table 1). Presumably due to crystal-packing effects, the arylated TEE moieties in the hybrid systems show substantial distortions from planarity, with the dihedral angles between the planes of the central TEE core and the adjacent aryl substituents amounting to 448. The switching properties were investigated by electronic absorption spectroscopy. Upon light absorption, DHAs 1, 12 ± 16, and 18 underwent retro-electrocyclization in solution to give the corresponding VHFs (Figs. 6, 11, and 12). The reaction is thermally reversible, with half-lives t 1/2 between 3.9 and 5.8 h at 258 in CH 2 Cl 2 (Figs. 7 and 13 and Table 3). A comparatively slower (E) 3 (Z) isomerization process about the central CC bond of the TEE moiety was also observed. The N,N-dimethylanilino-(DMA) substituted TEE-DHA hybrid systems trans-11a and cis-11a did not react to the corresponding VHFs upon irradiation (Scheme 9). Instead, only the reversible (E) 3 (Z) photoisomerization of the TEE core occurred (Fig. 16 and Table 4). This process was further investigated for photofatigue by electronic-emission spectroscopy (Fig. 17). After protonation of the DMA group, the usual DHA 3 VHF photoreaction took place. Compound 11 represents a three-way chromophoric molecular switch with three addressable sub-units (TEE core, DHA/VHF moiety, and proton sensitive DMA group) that can undergo individual, reversible switching cycles (Scheme 9). A process modeling the function of an AND logic gate (Fig. 19) and three write/erase processes could be performed with this system. Cyclic and linear sweep-voltammetry studies in CH 2 Cl 2 ( Bu 4 NPF 6 ) revealed the occurrence of characteristic first-reduction steps in the TEE-DHA hybrid systems between À 1.6 and À 1.8 V vs. Fc/Fc (ferrocene/ferricinium couple) ( Table 5). Oxidations occur at ca. 1.10 V. After photoisomerization to the VHF derivatives, reduction steps at more positive and oxidation steps at more negative potentials were recorded. No DHA 3 VHF isomerization took place upon electrochemical oxidation or reduction (Fig. 20).

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Section: Scheme 8 Synthesis Of Cis-11amentioning

confidence: 99%

Photoswitchable Tetraethynylethene-Dihydroazulene Chromophores

Gobbi¹,

Seiler²,

Diederich³

et al. 2001

HCA

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“…Furthermore, for several organic compounds a multimode photochromism has been observed (Iyoda et al, 1989;Achatz et al, 1991;Spreitzer and Daub, 1996;Pina et al, 1997;Mrozek et al, 2001). However, all of these systems need combined light excitation and a second external stimulus (rise of temperature or oxidation/reduction of the system) to perform a complete change between the different states.…”

Section: Four-states Data Storage On An Irisfp Coated Surfacementioning

confidence: 98%

Data storage based on photochromic and photoconvertible fluorescent proteins

Adam¹,

Mizuno²,

Grichine³

et al. 2010

Journal of Biotechnology

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“…Daub and co-workers [15][16][17] investigated redox-controlled switching of DHAs functionalized by ferrocene, anthraquinone, or heteroaryl groups in the five-membered ring. Interestingly, the neutral ferrocene-DHA conjugate was not photoactive, while instead the cation underwent ring opening upon irradiation [15].…”

Section: Figmentioning

confidence: 99%

New routes to functionalized dihydroazulene photoswitches

Nielsen

Broman

Petersen

et al. 2010

Pure and Applied Chemistry

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Molecular photoswiches are important for the development of advanced materials and molecular electronics devices. The dihydroazulene (DHA) is a particularly attractive molecule as it undergoes a light-induced ring opening to a vinylheptafulvene (VHF) isomer with altered optical properties. While functionalization of the five-membered ring of DHA has been possible for the last 25 years, this was not the case for the seven-membered ring. This article summarizes our synthetic efforts in achieving this goal. Incorporation of an alkyne at C-7 was accomplished by (i) regioselective bromination of DHA, followed by (ii) elimination of HBr, and (iii) Pd-catalyzed cross-coupling with triisopropylsilylacetylene. Light-induced ring opening of this DHA followed by thermal ring closure provided a mixture of 6-and 7-substituted DHAs with different absorption characteristics. The isomer ratio was controlled by the wavelength of irradiation and the solvent polarity. The dibromide formed in the initial step served as a precursor for a 3-bromo-functionalized azulene that was employed as a building block for acetylenic scaffolding. Incorporation of a dithiafulvene (DTF) unit at the five-membered ring of DHA resulted in a significant red-shift in the longest-wavelength absorption and consequently a lowering of the energy required for ring opening. Incorporation of a redox-active tetrathiafulvalene (TTF) unit allowed for redox-controlled photoswitching.Scheme 4 Synthesis of functionalized azulenes starting from the dibromide 8.Scheme 5 Incorporation of redox-active DTF and TTF units.

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Functionalized photochromics for molecular switching: the multistabilities of a dihydroazulene–anthraquinone system

Cited by 55 publications

References 12 publications

Photoswitchable Tetraethynylethene-Dihydroazulene Chromophores

Photoswitchable Tetraethynylethene-Dihydroazulene Chromophores

Data storage based on photochromic and photoconvertible fluorescent proteins

New routes to functionalized dihydroazulene photoswitches

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