Review of laser flash photolysis of organic molecules (2015–2018)

Shields, Dylan J.; Chakraborty, Mrinal; Abdelaziz, Nayera; Duley, Anju; Guđmundsdóttir, Anna D.

doi:10.1039/9781788016520-00070

Cited by 4 publications

(3 citation statements)

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“…Recientemente se han evaluado los principales factores que afectan su síntesis, y especialmente, los métodos de funcionalización orientados hacia la preparación de materiales mesoporosos basados en MCM-41. Este tipo de tecnología de adsorción ha atraído mucha atención, debido a que es una técnica que requiere el uso de pocos pasos y equipos, es de fácil operación y bajo costo, no genera residuos ni subproductos, es ecológica y de alta eficiencia energética, lo que permite su amplia aplicación en los procesos de remediación (Shields et al, 2020). Polioxometalatos de tipo Keggin H3PW12O40 (PW12), H3PMo12O40 (PMo12) y H4SiW12O40 (SiW12), soportados en polianilina (PANI) recubierta con nanopartículas de CuS (lo cual se realiza mediante un método de modificación gradual sencillo), fueron elaborados y evaluados como dispositivos de adsorción de azul de metileno (MB) y naranja de metilo (MO) (Siadatnasab, Karami & Khataee, 2019).…”

Section: Aplicación De Bases De Schiff Para El Diseño De Materiales Con Potencial Uso En Remediación De Fuentes Hídricasunclassified

Sinergismo para la solución de problemas ambientales: remediación de fuentes hídricas mediante el empleo de bases de Schiff

2020

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Las fuentes de agua potable, necesarias para garantizar la salud de los seres vivos y el medioambiente, son cada vez más escasas. Esta grave problemática exige el desarrollo de nuevas tecnologías eco-amigables que permitan el monitoreo de metales pesados, la prevención y, especialmente, la remediación de fuentes hídricas contaminadas. Dada la necesidad de orientar las investigaciones hacia el diseño de materiales capaces de retener o facilitar la eliminación de contaminantes con alta eficiencia y efectividad, en este artículo se presentan algunos de los últimos avances respecto al desarrollo de nuevos métodos de remediación de agua empleando bases de Schiff, una familia de moléculas de gran importancia en química. Los resultados de estas investigaciones demuestran su capacidad quelatante y como agente catalizador, en especial, su potencial aplicación para fines ambientales, siendo aún un conjunto de investigaciones incipien-tes, con mucho por explorar en este campo de la ciencia y la ingeniería.

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Section: Aplicación De Bases De Schiff Para El Diseño De Materiales Con Potencial Uso En Remediación De Fuentes Hídricasunclassified

Sinergismo para la solución de problemas ambientales: remediación de fuentes hídricas mediante el empleo de bases de Schiff

2020

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“…Photoreactivity in argon matrices is generally followed using IR spectroscopy, whereas solid-state reaction mechanisms are typically elucidated using laser flash photolysis of nanosuspensions or diffuse reflectance laser flash photolysis of solids . However, as not all radicals absorb strongly, laser flash photolysis detection can be difficult.…”

Section: Introductionmentioning

confidence: 99%

α-Cleavage of 2,2-Diazido-2,3-dihydroinden-1-one in Solution and Cryogenic Matrices

James,

Sriyarathne,

Banerjee

et al. 2024

J. Org. Chem.

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The Norrish type I (α-cleavage) reaction is an excellent photochemical method for radical-pair formation in solution. However, in cryogenic matrices, the starting material typically re-forms before the radical pair diffuses apart. This study focused on N 2 extrusion from an azido alkyl radical to prevent radical-pair recombination. Irradiation of 2,2-diazido-2,3-dihydroinden-1-one (1) in methanol mainly yielded methyl 2cyanomethylbenzoate (2) and 2-cyanomethylbenzoic acid (3) via α-cleavage. Laser flash photolysis of 1 in argon-saturated acetonitrile resulted in α-cleavage to form triplet biradical 3 1Br1 (λ max ∼ 410 nm, τ ∼ 400 ns). In contrast, upon irradiation in glassy 2-methyltetrahydrofuran matrices, triplet alkylnitrene 3 1N was directly detected using electron spin resonance (D/hc = 1.5646 cm −1 , E/hc = 0.00161 cm −1 ) and absorption spectroscopy (λ max = 276 and 341 nm). Irradiation of 1 in argon matrices generated 3 1N, benzoyl azide 4, singlet benzoylnitrene 1 4N, and isocyanide 5, as revealed by IR spectroscopy. The experimental results supported by density functional theory calculations [B3PW91/6-311+ +G(d,p)] suggest that irradiation of 1 in matrices results in α-cleavage to form biradical 3 1Br1, which extrudes N 2 to yield 3 1Br2. Rearrangement of 3 1Br2 into 3 1N competes with cleavage of a N 3 radical to form radical 1Ra3. The N 3 /1Ra3 radical pair combines to form 4, which upon irradiation yields 1 4N and 5.

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“…Thus, the understanding of solid-state reactions has typically relied on structure–reactivity correlations, such as those obtained by Schmidt in the 1960s for trans -cinnamic acids . Recent work by Garcia-Garibay and collaborators − has provided an innovative solution by adapting a reprecipitation method first described by Kasai et al to suspend nanocrystals in a solvent. This approach allows for time-resolved spectroscopic analyses because the average size of the crystals is smaller than the irradiation wavelength. , …”

Section: Introductionmentioning

confidence: 99%

Unraveling the Solid-State Photoreactivity of Carbonylbis(4,1-Phenylene)dicarbonazidate with Laser Flash Photolysis

Ahmed,

Kavikarage,

Judkins

et al. 2023

J. Phys. Chem. A

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Solid-state photoreactions are generally controlled by the rigid and ordered nature of crystals. Herein, the solution and solid-state photoreactivities of carbonylbis(4,1-phenylene)dicarbonazidate (1) were investigated to elucidate the solid-state reaction mechanism. Irradiation of 1 in methanol yielded primarily the corresponding amine, whereas irradiation in the solid state gave a mixture of photoproducts. Laser flash photolysis in methanol showed the formation of the triplet ketone (TK) of 1 (τ ∼ 99 ns), which decayed to triplet nitrene 3 1N (τ ∼ 464 ns), as assigned by comparison to its calculated spectrum. Laser flash photolysis of a nanocrystalline suspension and diffuse reflectance laser flash photolysis also revealed the formation of TK of 1 (τ ∼ 106 ns) and 3 1N (τ ∼ 806 ns). Electron spin resonance spectroscopy and phosphorescence measurements further verified the formation of 3 1N and the TK of 1, respectively. In methanol, 3 1N decays by H atom abstraction. However, in the solid state, 3 1N is sufficiently long lived to thermally populate its singlet configuration (1 1N). Insertion of 1 1N into the phenyl ring to produce oxazolone competes with 3 1N cleavage to form a radical pair. Notably, 1 did not exhibit photodynamic behavior, likely because the photoreaction occurs only on the crystal surfaces.

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Review of laser flash photolysis of organic molecules (2015–2018)

Cited by 4 publications

References 0 publications

Sinergismo para la solución de problemas ambientales: remediación de fuentes hídricas mediante el empleo de bases de Schiff

Sinergismo para la solución de problemas ambientales: remediación de fuentes hídricas mediante el empleo de bases de Schiff

α-Cleavage of 2,2-Diazido-2,3-dihydroinden-1-one in Solution and Cryogenic Matrices

Unraveling the Solid-State Photoreactivity of Carbonylbis(4,1-Phenylene)dicarbonazidate with Laser Flash Photolysis

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