Photo-, Thermo-, Solvato-, and Electrochromic Spiroheterocyclic Compounds

Минкин, Владимир И.

doi:10.1021/cr020088u

Cited by 862 publications

(618 citation statements)

References 172 publications

(151 reference statements)

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“…1 Among the best known photochromic molecules are spirooxazines which have been extensively investigated because they are expected to exhibit greater photostability than their spiropyran analogs. 2 Another advantage is their versatility, allowing modulation of their properties by playing with the position and nature of the substituents.…”

Section: Introductionmentioning

confidence: 99%

Solvation effect and aggregation of semipermanent spiro[indole-phenanthrolinoxazines] in CH3CN / H2O binary solvent

Gaeva¹,

Metelitsa²,

Voloshin³

et al. 2005

Arkivoc

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Section: Introductionmentioning

confidence: 99%

Solvation effect and aggregation of semipermanent spiro[indole-phenanthrolinoxazines] in CH3CN / H2O binary solvent

Gaeva¹,

Metelitsa²,

Voloshin³

et al. 2005

Arkivoc

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“…22 Similar solvatochromic effects were not observed for SO as the compound did not contain a solvatochromic moiety. …”

Section: Polarity and Solvatochromic Effectsmentioning

confidence: 73%

Investigating Nanostructuring within Imidazolium Ionic Liquids: A Thermodynamic Study Using Photochromic Molecular Probes

et al. 2009

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Following previous studies involving the thermal relaxation of spirocyclic compounds we extended our studies to investigate the formation of nano-structured domains in ionic liquids (ILs). Two compounds, spiropyran (BSP) and spirooxazine (SO) were added to imidazolium cation based ionic liquids with increasing chain lenghts (C 2 -C 12 ). Increasing side-chain length was found to have only minor effects on the rate of thermal relaxation of BSP and SO. BSP was found to be a suitable probe molecule as linear correlations in parameters were observed for this compound. This is believed to be due to the fact that BSP-IL interactions were based on hydrogen bonding between MC BSP and the cation compared to MC SO The resulting reorganisation of the system produced positive entropies of activation, 13.79 J.K -1 .mol -1 for C 4 mIm to 46.15 J.K -1 .mol -1 for C 12 mIm, following an increase in disorder due to probe dye closure from MC to BSP and migration of dye to regions of preferential solvation. The ability for spirocyclic compounds to form both polar and non-polar isomers resulted in the ability to analyse both solvent regions using a single probe dye. Ground state equilibrium, K e , examined non-polar regions of the IL while equilibrium of activation, K ‡ , examined the polar regions. A linear response to side chain length to equilibrium of activation was believed to be due to the fact that polar regions were possibly expanding due to increasing influence of non-polar side chain interactions upon the over solvent structure. The result of such reordering and dispersion of polar regions reduces solvent-solute interactions which increases rate of MC-BSP relaxation.

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“…Cis-trans isomerisation of the molecule results in a planar molecule with a delocalised charge across the molecule forming a zwitterionic/quinoid system. 10 The resulting delocalisation of charge also shifts the absorbance of the molecule into the visible region of the spectum allowing for spectroscopic verification of the switching process (figure 1b). The compound can also be returned to its closed, colourless form by irradiation with white light or through thermal reversion in the dark.…”

Section: Introductionmentioning

confidence: 99%

Photochromic imidazolium based ionic liquids based on spiropyran

Coleman

Byrne

Alhashimy

et al. 2010

Phys. Chem. Chem. Phys.

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We investigate the photo, solvate and thermochromic properties of a novel photoswitchable spiropyran derivative; SP Im in imidazolium based ionic liquids (ILs). SP Im was prepared by alkylation of the photoswitchable compound to an imidazolium cation and is added to imidazolium based ILs with increasing chain length to examine the stability of funtionalised cations its merocyanine (MC) and spiropyran (SP) forms and compared to standard spiropyran; BSP. The rate of thermal relaxation of the new derivative is found to be about ten times faster than that of BSP as reflected in rates of 13.9 x10 -3 s -1 and 1.0 x10 -3 s -1 for SP Im and BSP respectively in [C 6 mIm][NTf 2 ]. Since ILs are believed to form nano-structured domains it is proposed that the covalent attachment of the imidazolium side group of SP Im fully integrates the photoswitchable moiety into the non-polar region through side-chain association. In contrast, unbound BSP is relatively free to migrate between both polar and non-polar regions and the MC form is more readily stablised by the IL charge via through space interactions and spontaneous movement to charged nano-domains leading to enhancement of the MC lifetime. At higher concentrations, rheological and transport properties were investigated to determine the impact of covalent attachment of the BSP fragment to an imidazolium cation had upon the ionic liquid structure. Ionic Conductivity was found to decrease by up to 23% for SP Im with effects increasing with cation side-chain length. Unlike BSP, the photoswitching of the SP Im did not affect conductivity or viscosity values. This may indicate that the mobility of the photoswitchable compound and the resulting disruption of such movement may be critical to the evolution of this physical property.2

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Photo-, Thermo-, Solvato-, and Electrochromic Spiroheterocyclic Compounds

Cited by 862 publications

References 172 publications

Solvation effect and aggregation of semipermanent spiro[indole-phenanthrolinoxazines] in CH3CN / H2O binary solvent

Solvation effect and aggregation of semipermanent spiro[indole-phenanthrolinoxazines] in CH3CN / H2O binary solvent

Investigating Nanostructuring within Imidazolium Ionic Liquids: A Thermodynamic Study Using Photochromic Molecular Probes

Photochromic imidazolium based ionic liquids based on spiropyran

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