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.

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

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.

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.

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.

Thermal isomerization of spiropyran to merocyanine in aqueous media and its application to colorimetric temperature indication

Shiraishi, Yasuhiro,Itoh, Masataka,Hirai, Takayuki

, p. 13737 - 13745 (2010)

Thermally-induced isomerization of spiropyran derivatives in aqueous media has been studied. The colorless spirocyclic (SP) forms of spiropyran derivatives are isomerized to colored merocyanine (MC) forms even in dark conditions at elevated temperature. Equilibrium, kinetic, and deuterium experiments reveal that the thermal SP → MC isomerization is due to the stabilization of MC form by a hydrogen bonding interaction with water molecules. This leads to the ground state energy of the MC form decreasing to lower than that of the SP form, resulting in SP → MC isomerization. The thermal isomerization property is applicable to a rough indication of solution temperature. The spiropyran derivatives, when dissolved in aqueous media under irradiation of visible light with an appropriate light intensity, demonstrate an increase in MC absorbance with a rise in temperature. The absorption response occurs reversibly regardless of the heating/cooling sequence. The spiropyran derivatives therefore have a potential for colorimetric temperature indication.

Flannery,jun.

, p. 5660 (1968)

Photo- and solvatochromic properties of nitrobenzospiropyran in ionic liquids containing the [NTf2]- anion

Byrne, Robert,Fraser, Kevin J.,Izgorodina, Ekaterina,MacFarlane, Douglas R.,Forsyth, Maria,Diamond, Dermot

, p. 5919 - 5924 (2008)

The photo-, thermo- and solvatochromic properties of 2,3-dihydro-1′, 3′,3′-trimethyl-6-nitrospiro-[1-benzopyran-2,2′-1H-indole] (BSP-NO2) were studied in ILs containing the anion [NTf 2]- by UV-Vis absorption spectroscopy, ab initio molecular orbital theory and density functional theory (DFT) calculations. It was found that the kinetics and thermodynamics of the BSP-NO2 ? MC (merocyanine) equilibrium was sensitive to the nature of the cation. It was also observed that the imidazolium cation can form a through-space orbital interaction with the MC isomer, rather than a simple electrostatic interaction, thus preventing the MC conversion back to the BSP-NO2 isomer. The BSP-NO2 ? MC equilibrium thus serves as a model system for studying modes of interaction of the cations in ionic liquids. the Owner Societies.

Transmission spectroscopy and kinetics in crystalline solids using aqueous nanocrystalline suspensions: The spiropyran-merocyanine photochromic system

Breslin, Vanessa M.,Garcia-Garibay, Miguel A.

, p. 637 - 642 (2017)

A comparison of the solution and solid state thermal decay kinetics of five photochromic spiropyrans with different N-Alkyl groups (SP1-SP5) was carried out in acetonitrile and nanocrystalline suspensions at 298 K. The change in absorbance at ca. 550 nm was measured as a function of time for the merocyanine (MC) using transmission UV-vis spectroscopy. We found that the thermal decay kinetics are slower and follow a biexponential decay in the solid state compared to a faster, monoexponential decay that was measured in solution. We observed that, while the kinetic range measured in solution varies by a factor of 13, the decay kinetics in the solid state cover a range of ca. 150, indicating that crystal packing has an influence much greater than that of the effects of N-Alkyl substitution. A fluorescence analysis of irradiated samples of SP1 in solution could be used to determine the formation of the MC species and its subsequent decay. By contrast, a similar analysis of nanocrystalline suspensions displayed changes as a function of time that are consistent with selfquenching.

ASSOCIATION OF PHOTOCHROMIC 6-NITROINDOLINOSPYROPYRANS IN A NONPOLAR SOLVENT

Arsenov, V. D.,Parshutkin, A. A.,Marevtsev, V. S.,Cherkashin, M. I.

, p. 1799 - 1806 (1984)

-

THERMAL AND PHOTOSTABILITY OF 5',7'-DIALKOXY-5,6'-DINITRO-1,3,3,-TRIMETHYLSPIRO(INDOLIN-2,2'-CHROMENES)

Arsenov, V. D.,Manakova, I. V.,Przhiyalgovskaya, N. M.,Suvorov, N. N.

, p. 961 - 964 (1987)

Some photochromic indoline spiropyrans have been synthesized and their thermal and photostability examined in films and in solution.Introduction of the NO2 group into the indoline moiety of the molecule stabilized the spiropyran form in solution and in films, but blocking the NO2 group in the pyran moiety by adjacent alkoxy groups enhances the light stability of the compounds.

Photocyclization of diarylethenes: The effect of imidazole on the oxidative photodegradation process

Zakharov,Lvov,Rostovtseva,Metelitsa,Chernyshev,Krayushkin,Yadykov,Shirinian

, p. 1101 - 1109 (2019)

We have studied the photoreaction of 1,2-diarylethenes under aerobic conditions in the presence of various amines to prevent side processes promoted by singlet oxygen. It has been found that the most amines quite effectively deactivate processes associated with singlet oxygen, but primary and secondary amines unlike tertiary ones, react with substrates resulting in various side products. Among the studied amines, the most effective additive for preventing side processes, including those associated with singlet oxygen is imidazole, which is practically not consumed in photoreaction. It was shown that imidazole can also prevents the photodegradation of organic photochromes in solutions. The results obtained can be used in various branches of science, technology and medicine to improve the photostability of photosensitive organics (dyes).

Photochromism and photopolymerization induced mesophase transitions in mixtures of spiropyran and mesogenic diacrylate

Kim, Namil,Lam, Harris,Kyu, Thein

, p. 16381 - 16387 (2010)

A phase diagram of a binary mixture of photochromic molecule (spiropyran) and mesogenic diacrylate monomer has been established by means of differential scanning calorimetry and polarized optical microscopy. Subsequently, a theoretical phase diagram has been calculated by self-consistently solving the combined Flory-Huggins free energy for isotropic mixing, Maier-Saupe free energy for nematic ordering, and phase field free energy for crystal solidification. The phase diagram thus obtained consists of various coexistence regions involving single-phase crystals, pure nematic, crystal + liquid, crystal + nematic, and crystal + crystal coexistence gaps. Under UV irradiation, both SP and SP/RM257 mixtures showed the lowering trend of the melting points, which may be attributed to the plasticization effect by the merocyanine isomers. When UV light is illuminated on the 2/98 SP/RM257 mixture for an extended period, mesogenic diacrylate in the mixtures gets polymerized, showing the permanent fixation of isotropic and nematic structures due to the network formation of RM257 caused by the biradicals in the merocyanine intermediate.

Photochromism of nitrobenzospiropyran in phosphonium based ionic liquids

Byrne, Robert,Coleman, Simon,Fraser, Kevin J.,Raduta, Ana,MacFarlane, Douglas R.,Diamond, Dermot

, p. 7286 - 7291 (2009)

The photo-, thermo- and solvatochromic properties of 2,3-dihydro-1′, 3′,3′-trimethyl-6-nitrospiro[1-benzopyran-2,2′-1H-indole] (BSP) and its photo-induced merocyanine isomer (MC) were investigated in phosphonium based ILs by UV-vis absorption spectroscopy. It was found that the kinetics and thermodynamics of the BSP ? MC equilibrium were sensitive to the nature of the anion. The MC λmax shifted from 560 nm to 578 nm when in solutions of [P1,4,4,4][tos] and [P 6,6,6,14][dca], respectively. The BSP isomer was highly favoured at equilibrium in the ILs studied; Ke values observed were similar to non-polar solvents such as dichloromethane. The thermal relaxation of MC in all ILs is first order, and in comparison with aprotic polar solvents possessing comparable polarity (such as acetonitrile). Thermal relaxation rates of MC were monitored over a range of temperatures; at 293 K rates varied from 5.19 to 25.03 × 10-4 s-1. A non-linear relationship between Ke and k was observed; this contradicts what is expected for BSP in molecular solvents and suggests the isomers exhibit different molecular/solvation environments. The energetics of the thermal relaxation of MC in ILs were observed; activation energies ranged from 71 to 90 kJ mol -1 and all ILs exhibit negative activation entropies ranging between -72 and -8.2 J K-1 mol-1. A linear relationship between activation energy and entropy was observed.

Micro-environmental fine-tuning of electronic and kinetic properties of photochromic dyes

Whelan, Jamie,Abdallah, Dalia,Wojtyk, James,Buncel, Erwin

, p. 5727 - 5735 (2010)

Despite the recognition of the importance of Spiropyran (SP)-Merocyanine (MC) photochromic materials in molecular switching, the majority of studies have been reported in solution with relatively few in the solid-state as required in modern displays and other devices. In contrast, the present work bridges solution, condensed phase and solid-phase media and is to our knowledge the first micro-environmental study on electronic and kinetic effects for the SP-MC system. Expanding on our previous work we have investigated the photochromic properties of an SP molecule (1b) attached to a 100 μm commercially available polystyrene micro-particle (Wang Resin). The thermal MC → SP reversion kinetics (5a,b → 4a,b and 2a,b → 1a,b) which reflect the critical lifetime of the open MC form were measured. Reduction in kobs of thermal reversion, MC → SP, up to two orders of magnitude, and a blue-shift up to 58 nm was observed with the potential for tailoring or fine tuning. The use of polymeric micro-particles in controlling both electronic and kinetic properties of photochromic molecular switches has been highlighted. The Royal Society of Chemistry 2010.

Reversible regulation of pyrene excimer emission by light and metal ions in the presence of photochromic spiropyran: Toward creation of a new molecular logic circuit

Guo, Xuefeng,Zhang, Deqing,Wang, Tongxin,Zhu, Daoben

, p. 914 - 915 (2003)

The excimer fluorescence of a bis-pyrene molecule can be reversibly regulated by ultraviolet light, metal ions and visible light in the presence of spiropyran. Based on this result, a new molecular logic circuit is proposed.

Reversible photorheological fluids based on spiropyran-doped reverse micelles

Lee, Hee-Young,Diehn, Kevin K.,Sun, Kunshan,Chen, Tianhong,Raghavan, Srinivasa R.

, p. 8461 - 8463 (2011)

We describe a new class of photorheological (PR) fluids whose rheological properties can be reversibly tuned by light. The fluids were obtained by doping lecithin/sodium deoxycholate (SDC) reverse micelles with a photochromic spiropyran (SP) compound. Initially, the lecithin/SDC/SP mixtures formed highly viscoelastic fluids, reflecting the presence of long, wormlike reverse micelles. Under UV irradiation, the SP was isomerized to the open merocyanine (MC) form, causing the fluid viscosity to decrease 10-fold. When the UV irradiation was switched off, the MC reverted to the SP form, and the viscosity recovered its initial value. This cycle could be repeated several times without loss of response. The rheological transitions are believed to reflect changes in the lengths of the reverse worms. To our knowledge, this is the first example of a simple, reversible PR fluid that can be made entirely from commercially available components.

Synthesis of stereochemically-biased spiropyrans by microwave-promoted, one-pot alkylation-condensation

Perry, Alexis,Davis, Kane,West, Lara

, p. 7245 - 7254 (2018)

A microwave-assisted, two-step, one-pot synthesis of spiropyrans has been developed. This process was used to synthesise a range of sterically-congested spiropyrans from readily available precursors, employing environmentally benign solvents. The unusual substituent pattern possessed by these structures has been shown to influence the stereoselectivity of spiropyran ring-closure.

Determination of critical aggregation concentrations of self-assembling lipids in nonpolar organic media using spiropyrans as photochromic probes

Hachisako, Hiroshi,Nakayama, Hiroki,Ihara, Hirotaka

, p. 1165 - 1166 (1999)

Critical aggregation concentrations of organic gel-forming lipids in nonpolar organic media such as benzene were found to be determined by measuring the first-order rate constants of merocyanine-to-spiropyran thermal isomerizations for spiropyrans added as probes.

A colour tunable microcavity by weak-to-strong coupling regime transition through a light-switchable material

Accorsi, Gianluca,Carallo, Sonia,Mazzeo, Marco,Genco, Armando,Gambino, Salvatore,Gigli, Giuseppe

, p. 1122 - 1124 (2014)

An organic based microcavity showing fully reversible colour tunability has been achieved for the first time. The emission output changes according to the modulation from pure photonic to polaritonic resonant modes through UV irradiation of the light-switchable matrix.

Time-resolved thermodynamic profile upon photoexcitation of a nitrospiropyran in cycloalkanes and of the corresponding merocyanine in aqueous solutions

Williams, Rene M.,Klihm, Gudrun,Braslavsky, Silvia E.

, p. 2557 - 2576 (2001)

The photoconversion of 2′,3′-dihydro-6-nitro-1′,3′,3′- trimethylspiro[2H-1-benzopyran-2,2′-indole] (Sp) to its open merocyanine form (Mc) in a series of aerated cycloalkanes (cyclopentane, cyclohexane, and trans- and cis-decalin) and of the protonated merocyanine (McH+) to Sp in aqueous solution were studied by laser-induced optoacoustic spectroscopy (LIOAS), The + (11 ± 2) ml mol-1 expansion determined for the ring closure is due to deprotonation of McH+ plus the reaction of the ejected proton with the monoanion of malonic acid (added to stabilize Mc), an intrinsic expansion and a small electrostriction term. The energy difference between Sp and initial McH+ is (282 ± 110) kJ mol-1. An intrinsic contraction of - (47 ± 15) ml mol-1 occurs upon ring opening, forming triplet 3Mc in the cycloalkanes, whereas no volume change was detected for the 3Mc to Mc relaxation. Electrostriction decreases the 3Mc energy, (165 ± 18) kJ mol-1; to 135 kJ mol-1. The difference in the values of the ring-opening (Sp to Mc) reaction enthalpy in cycloalkanes as derived from the temperature dependence of the Sp?Mc equilibrium, (29 ± 8)kJ mol-1, and from the LIOAS data, - (9 ± 25) kJ mol-1, is due to the formation of Mc-Sp aggregates during steady-state measurements. The Sp-sensitized singlet molecular oxygen, O2(1Δg), quantum yield (average ΦΔ = 0.58 ± 0.03) derived from the near-IR emission of O2(1Δg), was taken as a measure of Mc production in the cycloalkanes. These solvents, albeit troublesome in their handling, provide an additional series for the determination of structural volume changes in nonaqueous media, besides the alkanes already used.

Mixed Solvent Chemistry through Synergistic Solvation: Structure, Property and Function of t-Butanol—Dichloromethane Binary Solvent Mixtures

Gupta, Shradhey,Parida, Keshaba Nanda,Mukherjee, Puspal,Sen, Pratik

, p. 461 - 475 (2017)

The present study elucidates the synergetic solvation behavior of t-butanol–dichloromethane (t-BuOH–DCM) binary solvent mixtures. UV–visible absorption, emission and 1H-NMR spectroscopy along with analytical modelling were used to ascertain the nature of interactions present, which are found to be maximum at Xt-BuOH?=?0.40, leading to a super solvation environment. The increased polarity of the t-BuOH–DCM binary solvent mixtures through interactive solvent association is believed provide a unique reaction medium that can alter the fate of chemical processes involving a polar species. This idea has been demonstrated by the transformation of merocyanine to 1′,3′-dihydro-,1′,3′,3′-trimethyl-6-nitropiro[2H-1-benzopyran-2,2′-(2H)-indole] and the oxidation of cholestanol to cholestanone.

Local molecular dynamics of poly(ethylene glycol) dimethacrylate synthesized in the presence of branched poly(methyl methacrylate): A photochromic probe study

Kurmaz,Ozhiganov,Berezin

, p. 1166 - 1171 (2009)

The local molecular dynamics and morphology of poly(ethylene glycol) dimethacrylate networks synthesized in the presence of 0-40% branched poly(methyl methacrylate) were studied using a photochromic probe (6-nitrospiropyran). The change in the free volume of the polymer in the vicinity of the photochromic probe was monitored by the rate of dark bleaching of merocyanine (colored form of 6-nitrospiropyran). The local free volume and the mobility of the polymer chain fragments decrease as the conversion of C=C bonds and the content of branched poly(methyl methacrylate) in the polymer increase. ; 2009 Springer Science+Business Media, Inc.

Synthesis method for producing 1,3,3-trimethylindolinobenzopyrylospiran through one-pot method

-

Paragraph 0016-0024, (2019/08/20)

The invention discloses a synthesis method for producing 1,3,3-trimethylindolinobenzopyrylospiran through a one-pot method, and belongs to the field of organic synthesis. The synthesis method for producing the 1,3,3-trimethylindolinobenzopyrylospiran through the one-pot method comprises the steps of using 2,3,3-trimethylindolenine, iodomethane and 5-nitrosalicylaldehyde as raw materials and usingalkali as a catalyst, and carrying out reaction to produce the 1,3,3-trimethylindolinobenzopyrylospiran. The method is simple in technology, the reaction is completed in one pot, in the reaction process, anhydrous and anaerobic operation is not needed, and the synthesis method for producing the 1,3,3-trimethylindolinobenzopyrylospiran through the one-pot method has the advantages that the synthesis efficiency is high, and little chemical waste is generated.