Results 191 to 200 of about 6,070 (236)
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Spiropyrans of the phenanthridine series
Chemistry of Heterocyclic Compounds, 1974The relative stabilities of the cyclic and open forms of spiropyrans of the phenanthridine series depend on the character and position of the substituents in the chromene ring and also on the polarity of the media. The structure of the open forms of the spiropyrans is closer to the limiting dipolar structure.
�. R. Zakhs +2 more
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ChemInform Abstract: Spiropyrans
ChemInform, 2000AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
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A photochemical synthesis of spiropyrans
Tetrahedron Letters, 1996Abstract A direct photochemical route to the synthesis of some spirobenzopyranochromones via H-abstraction is reported.
Satish C. Gupta +4 more
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Chemistry of Heterocyclic Compounds, 1980
A method was developed for the estimation of the relative stabilities of spirocyclic and merocyanine structures of spiropyrans on the basis of the Pariser-Farr-Pople method in δ,π parametrization with a corresponding estimate of the energy of formation of the spiro node.
B. Ya. Simkin, V. I. Minkin
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A method was developed for the estimation of the relative stabilities of spirocyclic and merocyanine structures of spiropyrans on the basis of the Pariser-Farr-Pople method in δ,π parametrization with a corresponding estimate of the energy of formation of the spiro node.
B. Ya. Simkin, V. I. Minkin
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Mechanism of photodecomposition of spiropyrans
Theoretical and Experimental Chemistry, 1990Spectrophotometric and ESR measurements have been made in a study of photodecomposition and thermodecomposition reactions of spiropyrans (SPs) of the indoline and oxaindan series of solutions and in the crystalline state, at various temperatures. From an analysis of the experimental data, involving certain concepts developed previously regarding the ...
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Photocontraction of Liquid Spiropyran-Merocyanine Films
Science, 1984Amorphous films of a photochromic spiropyran containing a mesogenic group melt, when exposed to heat together with irradiation, to yield a red fluid. This fluid contains aggregates of merocyanine molecules and exhibits marked contraction under light illumination.
I, Cabrera +3 more
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Spiropyran-Functionalized Hydrogels
2014Photoresponsive actuators composed of a hydrogel functionalized with spiropyran are described. The hydrogel exhibits drastic shrinking in rapid response to blue light irradiation in acidic aqueous systems, and is examined for the application of several photoresponsive actuator systems.
Kimio Sumaru +3 more
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Photoisomerization of Spiropyran for Driving a Molecular Shuttle
Organic Letters, 2007A novel light-powered molecular shuttle was synthesized which can switch the movement of a macrocycle between two distinct stations-dipeptide and zwitterionic ME-by exploiting the photoisomerization of spiropyran. The macrocycle resides selectively in the dipeptide station in the SP form and moves to the ME station under the irradiation of UV light ...
Weidong, Zhou +6 more
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Spiropyrans: Structural Features and Photochemical Properties
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, 1990Abstract It has been shown, that in the ground state the Cspiro−O bond, which is broken upon photoexcitation, is weakened and elongated because of specific orbital n-s* interactions. They become stronger in excited photochemically active state, thus facilitating the rupture of this bond.
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