1498-88-0Relevant academic research and scientific papers
Decoloration rates of a photomerocyanine dye as a visual probe into hydrogen bonding interactions
Ciampi, Simone,Eggers, Paul K.,Haworth, Naomi L.,Darwish, Nadim,Wagner, Pawel,Coote, Michelle L.,Wallace, Gordon G.,Raston, Colin L.
, p. 4815 - 4818 (2015)
We have developed a visual marker for the investigation of hydrogen bonding (HB) effects. The decoloration rate of a photochromic dye that incorporates a latent intra-molecular HB feature can be linked to the HB character of the media. Kinetic and thermodynamic parameters of this simple decoloration approach for HB sensing are investigated both experimentally and by high level theoretical studies. This principle has been applied for the detection of changes in the HB character of stationary and fluidic systems. A major finding is the observation of a shear-related perturbation of the balance between intra- and inter-molecular HB within a dynamic thin film.
Spiropyran as a reusable chemosensor for selective colorimetric detection of aromatic thiols
Shiraishi, Yasuhiro,Yamamoto, Kohei,Sumiya, Shigehiro,Hirai, Takayuki
, p. 12137 - 12142 (2014)
Design of optical molecular probes for selective detection of aromatic thiols has attracted much attention. Although several types of probes have been proposed, all of them exhibit colorimetric or fluorometric response via irreversible reaction with aromatic thiols and cannot be reused. Here we report that a spiropyran dye is the first example of a reusable chemosensor for aromatic thiols. A colorless spiropyran dye (1) dissolved in aqueous media containing aromatic thiols is selectively isomerized to the colored merocyanine form in the dark. In contrast, visible light irradiation of the merocyanine form promotes successful reversion to the colorless spirocyclic form. Kinetic absorption analysis and ab initio calculations of the transition states revealed that this colorimetric response in the dark is ascribed to the decrease in activation energy for isomerization via the nucleophilic interaction between the aromatic thiol and the olefinic carbon of the dye.
Dicondensed indolinobenzospiropyrans as precursors of thermo- and photochromic spiropyrans. Part II: Assignment of 1H and 13C NMR spectra
Keum, Sam-Rok,Ahn, Su-Mi,Roh, Se-Jung,Park, Su-Jin,Kim, Sung-Hoon,Kon, Kwangnak
, p. 90 - 94 (2006)
The 1H and 13C NMR spectra of dicondensed indolinobenzospiropyrans as precursors of thermo- and photochromic spiropyrans, DC1-DC5, were completely assigned. Especially, the 1H assignment and coupling characteristics of the diastereotopic protons at the carbon-3 position of the benzopyran rings were achieved by conducting 1H-1H COSY and nOe experiments. The dihedral angles (θ1, θ2 and θ3) calculated from the experimental values of the vicinal coupling constants (3J) of DC5 are in good agreement with the observed values in the solid state. All of the carbons in the DC dye molecules were investigated through a combination of heteronuclear 2D-shift correlation spectroscopy (HETCOR) and DEPT135. Copyright
Light induced tuning of quantum cascade lasers
Basnar,Mujagic,Andrews,Roch,Schrenk,Strasser
, (2010)
A method for tuning the emission of a midinfrared quantum cascade laser using ultraviolet light is presented. The method uses a quantum cascade laser where a photochromic material is deposited as the top waveguide cladding. Changing the state of the cladding causes variations in the absorbance of the cladding. Wavelength dependent changes in the waveguide losses occur, forcing the laser to emit at a wavelength correlated with an absorbance minimum of the cladding. A blueshift by about 6 cm-1 was obtained at room temperature under UV irradiation which was fully reversed by exposure to visible light or room temperature relaxation.
1',3',3'-Trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-indoline]: Its thermal enantiomerization and the equilibration with its merocyanine
Kiesswetter, Roland,Pustet, Nikola,Brandi, Friedrich,Mannschreck, Albrecht
, p. 4677 - 4687 (1999)
The enantiomers of the title compound, the important photochromic material (RS)-1b, have been enriched semipreparatively by liquid chromatography. As a consequence, we were able to determine the barrier of the thermal interconversion (R)-1b?(S)-1b via time-dependent polarimetry, amounting to ΔG(≠)=85.9 kJ/mol at 22.0°C in d6-DMSO (Table 2). The thermal equilibration of the corresponding merocyanine 2b was monitored in d6-DMSO by time-dependent 1H NMR, resulting in ΔG1(≠)=102.8 and ΔG2(≠)=92.0 kJ/mol at 22°C (Table 1). This means that, starting from (RS)-1b, the opened isomer 2b is attained by a slow reaction (ΔG1(≠)=102.8 kJ/mol, Fig. 4). Therefore, the merocyanine 2b cannot be identified with the intermediate required for the fast process of C(sp3)-O bond cleavage (ΔG(≠)=85.9 kJ/mol) upon the above enantiomerization of (RS)-1b. Apparently, these two thermal isomerizations (Fig. 4) are independent of each other. The structure of the unknown intermediate of the interconversion (R)- 1b?(S)-1b must therefore differ from the known one of merocyanine 2b. (C) 2000 Elsevier Science Ltd.
Photochromism of spiropyran in molecular sieve voids: Effects of host-guest interaction on isomer status, switching stability and reversibility
Schomburg,Wark,Rohlfing,Schulz-Ekloff,Woehrle
, p. 2014 - 2021 (2001)
Spiropyran or its preferred configurational isomers, respectively, are incorporated in faujasite (NaY, HY and DAY) cages by in situ synthesis, and in Si-MCM-41 channels by wetness impregnation. Luminescence spectra of the colored isomers indicate the non-aggregated incorporation of merocyanine forms. High quantum yields for the photochromism ( ～ 75%) demonstrate the ready access of the chromophores for the photons of the laser pulses, used for the photoinduced switching between the different configurational isomers. The strong retardation of the thermal relaxation rate from the photoproduct cis-merocyanine to the thermodynamically preferred trans-merocyanine in the faujasite hosts (HY, DAY) in comparison to spiropyrans in SiO2 or Al2O3 is attributed to an increase of the rotation barriers by the imposed spatial restrictions. Among the different faujasites the dealuminated Y-zeolite (DAY) exhibits the lowest relaxation rates of the photoproduct and the highest switching reversibilities between the trans- and the cis-merocyanine.
Effects of metal ion complexation on the spiropyran-merocyanine interconversion: Development of a thermally stable photo-switch
Wojtyk, James T.C.,Kazmaier, Peter M.,Buncel, Erwin
, p. 1703 - 1704 (1998)
Spectrophotometric absorption and fluorescence measurements of spiropyrans 2 and 3 modified with chelating functionalities, in the presence of Ca2+ and Zn2+, provide evidence of a thermally stable spiropyran-merocyanine photoswitch that is modulated by the metal cations.
Photochromism of a spiropyran and a diarylethene in bile salt aggregates in aqueous solution
Santos, Cerize S.,Miller, Allyson C.,Pace, Tamara C. S.,Morimitsu, Kentaro,Bohne, Cornelia
, p. 11319 - 11328 (2014)
Bile salt aggregates incorporate aqueous-insoluble photochromic compounds. The photochromism of a spiropyran (1, 1′,3′,3′-trimethyl-6-nitrospiro[2H-1]-benzopyran-2,2′-indoline) and a diarylethene derivative (2, 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluoro-1-cyclopentene) was quantified in different bile salt aggregates. These aggregates act as efficient hosts to solubilize aqueous insoluble photochromic compounds where either both isomers are nonpolar, for example, 2, or compounds where one isomer is hydrophobic and the other is more polar, for example, 1. Methodology was developed to determine molar absorptivity coefficients for solutions containing both isomers and to determine the photoconversion quantum yields under continuous irradiation. The methods were validated by determining parameters in homogeneous solution, which were the same as previously reported. In the case of the colored isomer of 1, the molar extinction coefficient in ethanol at 537 nm ((3.68 ± 0.03) × 104cm-1M-1) was determined with higher precision. The quantum yields for the photoconversion between the isomers of 2 were shown to be the same in cyclohexane and in the aggregates of sodium cholate (NaCh), deoxycholate (NaDC), and taurocholate (NaTC), showing that bile salt aggregates are not sufficiently rigid to affect the equilibrium between the two possible conformers of the colorless form. In contrast, for 1 the quantum yields for the conversion from the colorless to the colored isomer were higher in bile salts than in ethanol, and the quantum yield was highest in the more hydrophobic aggregates of NaDC, followed by NaCh and then NaTC. The structure of the bile salt had no effect on the quantum yield for the conversion of the colored to the colorless isomer of 1, but these values were higher than in ethanol. For all three bile salts, the absorption maximum for the colored form of 1 suggested that this isomer was located in an environment that is more polar than ethanol.
Characterization of organic photochromic materials as 3-D optical data storage media
Kawata, Satoshi,Amistoso, Jose Omar
, p. 23 - 30 (2000)
We present our work on data storage and characterization in photochromic materials, and have succeeded in recording data at a total of 26 overlapping layers. The effect of bit depth and bit size were investigated by varying exposure time of the sample to the laser pulses. Bit size and bit depth were found to increase with exposure time and optimizing their values would increase the density of the possible number of data stored in a photochromic medium.
Direct Access by Mechanochemistry or Sonochemistry to Protonated Merocyanines: Components of a Four-State Molecular Switch
Cola?o, Melwin,Carletta, Andrea,Van Gysel, Mégane,Robeyns, Koen,Tumanov, Nikolay,Wouters, Johan
, p. 520 - 526 (2018)
Direct access to the protonated merocyanine forms of two substituted spiropyrans by mechanosynthesis or sonochemistry was explored. The compounds were formed by the condensation reaction of the methyleneindolium iodide salt with salicylaldehyde derivatives. X-ray crystallography, 1H NMR spectroscopy, ab initio geometry optimization, and absorption spectroscopy were combined to provide a better understanding of the four-state molecular switch system in which the newly synthesized protonated merocyanines were found to play a central role. The results of this study suggest that the stability of the protonated merocyanines requires acidic conditions, as treatment with base led to the corresponding unprotonated merocyanines, which in turn spontaneously converted into photochromic closed spiropyrans.
