4n+2 Systems: Spiropyrans

Guglielmetti, R.

doi:10.1016/b978-044451322-9/50012-9

Cited by 26 publications

(11 citation statements)

References 190 publications

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“…References 2 and 3 present a good overview over the wide variety of potential applications of these compounds. The ring-opening process is accompanied by a strong increase of the ground-state dipole moment . But not much is known about the electric dipole moment of the first singlet excited states of the closed and open form.…”

Section: Introductionmentioning

confidence: 99%

Ground- and First-Excited-Singlet-State Electric Dipole Moments of Some Photochromic Spirobenzopyrans in Their Spiropyran and Merocyanine Form

Bletz¹,

Pfeifer-Fukumura²,

Kolb³

et al. 2002

J. Phys. Chem. A

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The dipole moments of four photochromic derivatives of indolinospirobenzopyran have been studied in their spiro and their open merocyanine form, in dioxane. Determinations have been done by electrooptical absorption measurements (EOAM). To prepare either a pure spiropyran or a pure merocyanine form solution, the experimental setup had to be modified by addition of a second light beam. In this way thermal equilibration between the spiropyran and the merocyanine form and switching from one form to the other induced by the measuring light beam could be avoided. The ground-state dipole moment of the spiro form amounts to (10-15) × 10 -30 C m and increases strongly to about 60 × 10 -30 C m with the excitation to the first excited singlet state. The ground-state dipole moment of the merocyanine form is much larger and amounts to (50-60) × 10 -30 C m. In contrast to the spiro form it decreases to about 40 × 10 -30 C m, when exciting to the first excited singlet state of the merocyanine form. † Part of the special issue "Noboru Mataga Festschrift".

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Section: Introductionmentioning

confidence: 99%

Ground- and First-Excited-Singlet-State Electric Dipole Moments of Some Photochromic Spirobenzopyrans in Their Spiropyran and Merocyanine Form

Bletz¹,

Pfeifer-Fukumura²,

Kolb³

et al. 2002

J. Phys. Chem. A

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“…6-Nitro-BIPS was purchased from Aldrich. 6,8-Dinitro-BIPS and 6-nitro-8-bromo-BIPS were prepared by standard synthetic routes . The preparation of the C3-deuterated forms was described previously. − It involves exchange from deuterium oxide layered over the MC forms dissolved in chloroform or evaporation of the solvent from a CH 3 OD solution.…”

Section: Methodsmentioning

confidence: 99%

Quadrupole Coupling Parameters of Olefinic Deuterons: ²H MAS NMR Spectroscopy of Photochromic Spiropyran and Merocyanines

Parker¹,

Hobley²,

Malatesta³

2002

J. Phys. Chem. A

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Three molecules with olefinic deuterons were obtained through H-D exchange of the C3 proton on the central bridging double bond of spiropyran photomerocyanines with deuterium oxide solution. Quadrupole coupling parameters were determined by simulation of the spinning sideband manifolds in spectra obtained using solid-state deuterium MAS NMR spectroscopy. The C3-deuterated forms of the closed-ring spiropyran 1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2-indoline] (3D-6-nitro-BIPS) and the open-ring merocyanines 1′,3′,3′-trimethyl-6,8-dinitrospiro[2H-1-benzopyran-2,2-indoline] (3D-6,8-dinitro-BIPS) and 1′,3′,3′-trimethyl-6-nitro-8-bromospiro[2H-1-benzopyran-2,2-indoline] (3D-6-nitro-8-bromo-BIPS) had the same quadrupole coupling constants (QCCs) of 176 ( 4 kHz. This value, the second reported for an olefinic deuteron, is slightly less than the QCCs known for rigid aromatic deuterons (180-185 kHz). The asymmetry parameters (η) for the latter two molecules (open rings) were 0.10 ( 0.03, slightly larger than that observed for the closed-ring 3D-6-nitro-BIPS (0.00 ( 0.03). This slight asymmetry of the electric field gradient around deuterium in the merocyanines is attributed to a small deviation of the C-D bond from perfect axial symmetry, probably resulting from a through-space interaction between C3-D and C9-O.

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“…Thus, a change of the polymer conformation and properties can be obtained photochemically, by introducing compounds like spiro benzopyran. The spiro benzopyran chromophores as well as the closely related spiro benzoxazines and spiro naphthoxazines are well known for the formation of a merocyanine zwitterion, by a ring-opening reaction (Bertelson, 1971;Bertelson, 1999;Guglielmetti, 2003). Upon irradiation with UV light, the rupture of the C-O linkage takes place, according to the mechanism shown in Fig.…”

Section: Polysaccharide Derivatives Forming Ionic Structures Upon Irrmentioning

confidence: 97%

Photoactive polysaccharides

Wondraczek

Kotiaho

Fardim

et al. 2011

Carbohydrate Polymers

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a b s t r a c tLight is a non-invasive stimulus or probe, which retains more and more attention in science and technology. In the present review the reader is informed about the important issue of the interactions of polysaccharides and light. Considering some aspects of polysaccharide structure and properties, topics such as absorption and fluorescence of polysaccharides, the structural analysis using light as a probe, and creation of new materials by combining chromophores and polysaccharides are discussed. Attention is also be given to polysaccharide derivatives, where absorption of light induces structural changes, including photocrosslinking and photochromism.

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4n+2 Systems: Spiropyrans

Cited by 26 publications

References 190 publications

Ground- and First-Excited-Singlet-State Electric Dipole Moments of Some Photochromic Spirobenzopyrans in Their Spiropyran and Merocyanine Form

Ground- and First-Excited-Singlet-State Electric Dipole Moments of Some Photochromic Spirobenzopyrans in Their Spiropyran and Merocyanine Form

Quadrupole Coupling Parameters of Olefinic Deuterons: ²H MAS NMR Spectroscopy of Photochromic Spiropyran and Merocyanines

Photoactive polysaccharides

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4n+2 Systems: Spiropyrans

Cited by 26 publications

References 190 publications

Ground- and First-Excited-Singlet-State Electric Dipole Moments of Some Photochromic Spirobenzopyrans in Their Spiropyran and Merocyanine Form

Ground- and First-Excited-Singlet-State Electric Dipole Moments of Some Photochromic Spirobenzopyrans in Their Spiropyran and Merocyanine Form

Quadrupole Coupling Parameters of Olefinic Deuterons: 2H MAS NMR Spectroscopy of Photochromic Spiropyran and Merocyanines

Photoactive polysaccharides

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Quadrupole Coupling Parameters of Olefinic Deuterons: ²H MAS NMR Spectroscopy of Photochromic Spiropyran and Merocyanines