Dithia-diaza[n. 2] paracyclophane-enes

Funke, Ulrike; Grützmacher, Hans‐Friedrich

doi:10.1016/s0040-4020(01)86864-2

Cited by 36 publications

(11 citation statements)

References 4 publications

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“…[83] Thermally stable cis isomers were isolated when the chain contains four, six and seven atoms, but these compounds photo chemically decomposed upon irradiation with UV light. A thermal equilibrium was observed, when the connecting chain was elongated to eight and nine atoms.…”

Section: Some Years Ago Grützmacher Synthesized Macrocyclic Azo Compomentioning

confidence: 99%

Shape‐Switchable Azo‐Macrocycles

et al. 2009

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The synthesis of four shape‐switchable macrocycles comprising different peripheral substituents is described. The macrocycles 1–4 consist of m‐terphenyl semicircles interlinked by two azo joints. These macrocycles were assembled from nitro‐functionalized m‐terphenyl moieties through reductive dimerization. The semicircles were assembled through Suzuki cross‐coupling reactions. The molecular weights of the macrocycles were determined by vapour pressure osmometry, because mass spectrometry failed in the cases of 2 and 3. The E → Z photoisomerization reactions were analysed by UV/Vis spectroscopy complemented by 1H NMR studies. A very slow thermal back‐reaction indicated considerable stabilization of the Z isomer. The reduced efficiency of the thermal back‐reaction probably arises from the reduced degree of freedom due to the mechanical interlinking of the two azo groups. The photostationary state consisted of all‐Z (85 %) and all‐E isomers (15 %). The E → Z transformation induced by irradiation displayed simple exponential kinetics, which indicates pairwise switching of the two azo groups in a macrocycle, at least on the timescale under investigation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Section: Some Years Ago Grützmacher Synthesized Macrocyclic Azo Compomentioning

confidence: 99%

Shape‐Switchable Azo‐Macrocycles

et al. 2009

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“…In some cases, bulky substituents can inhibit the cis ĺ trans relaxation process, thereby allowing the cis state to persist for days [15,16] . It is also worth noting that the cis form of the parent azobenzene can in fact be stabilized and isolated by crystallization [17,18] .…”

Section: Methodsmentioning

confidence: 99%

Principle of direct-inscribing diffractive phase elements by linearly polarized light

Duan

Wang

2009

2009 9th International Conference on Electronic Measurement &Amp; Instruments

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A novel method for fabricating diffractive phase elements on azobenezene polymer film is proposed. Distinguished from the common direct-inscribing systems, polarized light illuminates on sample films in this polarizedlight direct-inscribing system. By composite control of the intensity and polarization direction of the inscribing light and exposure time, a special phase-delay distribution graph can be achieved. Based on the proposal, a series of phase-type gratings were produced. Our speculation was supported by polarizing optical microscopy and scanning near-field optical microscopy (SNOM). Some qualitative analyses were made in the article. Compared with the holographic interference method, the one above is more flexible, and undemanding for the experimental environment. It may get extensive application.

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Section: Chapter 1: Azobenzene Polymers For Photonic Applicationsmentioning

confidence: 99%

“…Of course, one can also generate a system that starts in the cis state and where isomerization (in either direction) is completely hindered. For instance, attachment to a surface (Kerzhner et al, 1983), direct synthesis of ringlike azo molecules (Funke and Gruetzmacher, 1987), and crystallization of the cis form (Hartley, 1938(Hartley, , 1937 can be used to maintain one state, but such systems are obviously not bistable photoswitches.A bulk azo sample or solution under illumination will achieve a photostationary state, with a steady-state trans-cis composition based on the competing The trans and cis extinction coefficients are denoted by e trans and e cis . The F refer to quantum yields of photoisomerization, and g is the thermal relaxation rate constant.…”

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confidence: 99%