Spiropyran–Amidine: A Molecular Canary for Visual Detection of Carbon Dioxide Gas

Darwish, Tamim A.; Evans, Richard A.; James, M. R.; Hanley, Tracey

doi:10.1002/chem.201101723

Cited by 46 publications

(30 citation statements)

References 35 publications

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“…30 The reaction is reversible as the SP form could be restored either upon irradiation of the lm at 405 nm or through thermal recovery. In parallel, the generation of the exposed negative charge on the phenolic oxygen massively increases the basicity of the system 36 and, as a consequence, subsequent exposure of the lm to CF 3 COOH (TFA) vapors induces the protonation of the phenolate and the immediate color change from purple to yellow.…”

Section: Resultsmentioning

confidence: 99%

Photoactivated acidochromic elastomeric films for on demand acidic vapor sensing

2015

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The acid vapor sensing properties of photochromic elastomeric composite films based on spiropyran molecules embedded in poly(dimethylsiloxane) matrices are investigated. The conversion of the spiropyran molecules to their zwitterionic merocyanine isomers upon UV irradiation is essential for the acidochromic response of the composite system, in order to detect vapors of hydrochloric, trifluoroacetic, formic and acetic acids by means of the protonation of the phenolate ions. The formation of the protonated merocyanine species is accompanied by a change in the absorption spectrum and a clear color transition of the film. Differences in the protonation rate are observed for different acids due to the relative acidity of the vapors, and for different concentrations of merocyanine. The acidochromic detection can be switched on and off several times by UV irradiation and subsequent thermal regeneration of the non-polar spiropyran form with an excellent resistance to photodegradation.The facile method of preparation combined with the fast and reversible optical response activated on demand upon photoexcitation renders this material suitable for the development of portable sensing devices for environmental and industrial applications. † Electronic supplementary information (ESI) available: Optimized molecular geometry of MCH, absorption spectra of a SP/PDMS lm at different irradiation times, lm thickness dependence of the kinetics of protonation of UV irradiated SP/PDMS lms with different thicknesses exposed to vapors of TFA, kinetics of the formation of MCH upon exposure of UV irradiated SP/PDMS lms to vapors of HCl, TFA, HCOOH and AcOH, time evolution of the absorption peak of a MCH/PDMS lm at 417 nm, time evolution of the absorbance at 550 nm of a MC/PDMS lm 0-60 minutes aer UV irradiation, variation of the absorbance at 417 nm during protonation of SP/PDMS lms (SP ¼ 0.5% wt) and of SP/PDMS lms (SP ¼ 0.3% wt) with the same content of MC, video of the protonation of a UV irradiated SP/PDMS lm exposed to vapors of TFA for 9 minutes. To reduce the le size the speed has been accelerated 20Â with respect to the original rate. See

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Section: Resultsmentioning

confidence: 99%

Photoactivated acidochromic elastomeric films for on demand acidic vapor sensing

2015

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“…Newer types of CO2 sensors utilize secondary amines, amidines, guanidines, or in situ generated carbenes as liquid phase CO2 absorbent, in combination with a colorimetric or fluorescent indicator. [18][19][20][21][22][23][24][25][26] The mode of detection is dependent on the physical changes in the sensor media upon dissolution of CO2, such as viscosity, 18,19 pH or polarity 24,25 .…”

Section: Introductionmentioning

confidence: 99%

Sensitive colorimetric sensors for visual detection of carbon dioxide and sulfur dioxide

Chatterjee

Sen

2015

J. Mater. Chem. A

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Reusable, solid-supported colorimetric sensors, prepared from tertiary amino alcohols and pH-sensitive dyes, can detect ppm levels of gaseous CO 2 and SO 2 .A series of highly efficient, solid-state sensors for direct colorimetric detection of gaseous CO2 and SO2 is described. The basic components of the sensors are a CO2 and SO2-responsive, tertiary amino alcohol, such as triethanol amine, and a pH-indicator dye e.g. cresol red, immobilized on a porous -aluminum oxide support. These sensors show distinct visual responses to low levels of CO2 and SO2 present in air. A structure-performance relationship was also established for these sensors. To increase the shelf-life, the tertiary amino alcohols were covalently attached to the porous alumina support. These porous alumina-supported tertiary amino alcohols also offer potential for use as adsorbents for acidic gases such as CO2 and SO2 with the ability to selectively release these under different conditions, allowing easy separation from a gas stream.

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“…The assembly process of the (LDH/FAS) n membranes was monitored by UV–Vis absorption spectroscopy. Figure 2d shows two absorption bands at 224 and 272 nm attributed to FAS 34 , whose intensities increase almost linearly with the bilayer number (inset of Fig. 2d ), indicating a successful step-by-step and controllable growth process.…”

Section: Resultsmentioning

confidence: 91%

High-efficiency CO2 separation using hybrid LDH-polymer membranes

Wang

Zhou

et al. 2021

Nat Commun

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Membrane-based gas separation exhibits many advantages over other conventional techniques; however, the construction of membranes with simultaneous high selectivity and permeability remains a major challenge. Herein, (LDH/FAS)n-PDMS hybrid membranes, containing two-dimensional sub-nanometre channels were fabricated via self-assembly of unilamellar layered double hydroxide (LDH) nanosheets and formamidine sulfinic acid (FAS), followed by spray-coating with a poly(dimethylsiloxane) (PDMS) layer. A CO2 transmission rate for (LDH/FAS)25-PDMS of 7748 GPU together with CO2 selectivity factors (SF) for SF(CO2/H2), SF(CO2/N2) and SF(CO2/CH4) mixtures as high as 43, 86 and 62 respectively are observed. The CO2 permselectivity outperforms most reported systems and is higher than the Robeson or Freeman upper bound limits. These (LDH/FAS)n-PDMS membranes are both thermally and mechanically robust maintaining their highly selective CO2 separation performance during long-term operational testing. We believe this highly-efficient CO2 separation performance is based on the synergy of enhanced solubility, diffusivity and chemical affinity for CO2 in the sub-nanometre channels.

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Spiropyran–Amidine: A Molecular Canary for Visual Detection of Carbon Dioxide Gas

Cited by 46 publications

References 35 publications

Photoactivated acidochromic elastomeric films for on demand acidic vapor sensing

Photoactivated acidochromic elastomeric films for on demand acidic vapor sensing

Sensitive colorimetric sensors for visual detection of carbon dioxide and sulfur dioxide

High-efficiency CO2 separation using hybrid LDH-polymer membranes

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