Kinetics and mechanisms of nucleophilic displacements with heterocycles as leaving groups. Part 4. 2,4,6-Triaryl-N-benzylpyridinium cations: rate variation with electronic effects in the leaving group

Katritzky, Alan R.; Adamson, Jeffrey; Elisseou, E. Michael; Musumarra, Giuseppe; Patel, Ranjan C.; Sakizadeh, Kumars; Yeung, Wing Kai

doi:10.1039/p29820001041

Cited by 19 publications

(15 citation statements)

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“…The ratio Φ T /

Φ_{normalT}^{0}

is conveniently determined by taking the ratio of integrated triplet‐triplet absorption decay curves at 570 nm in the laser flash photolysis experiment in the presence and absence of the different concentrations of 1‐bromobutane. In the case of HPY 2+ , the quantum yield of triplet formation,

Φ_{normalT}^{0}

= 0.033 ± 0.02, is significantly smaller than that reported for TPP + ,

Φ_{normalT}^{0}

= 0.48 .

[\frac{Φ_{T}}{Φ_{normalT}^{0}} x \frac{Φ_{normalf}^{0}}{Φ_{f}} - 1] {normalΦ}_{T}^{0} = \frac{Φ_{normalf}^{0}}{Φ_{f}} - 1

…”

Section: Resultsmentioning

confidence: 64%

“…We initially adapted a method used extensively for the synthesis of pyrylium cations, as shown in Scheme , for the construction of HPY 2+ . The reaction is initiated by a base catalyzed condensation between acetophenone and pyridine‐4‐carbaldehyde to give an α‐, β‐unsaturated ketone that immediately undergoes a Michael addition with a second equivalent of acetophenone to give 1,5‐diketone 1 (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

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Synthesis, Characterization, Photophysics and Photochemistry of Pyrylogen Electron Transfer Sensitizers

Clennan

Liao

2013

Photochem & Photobiology

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A series of new dicationic sensitizers that are hybrids of pyrylium salts and viologens has been synthesized. The electrochemical and photophysical properties of these "pyrylogen" sensitizers are reported in sufficient detail to allow rationale design of new photoinduced electron transfer reactions. The range of their reduction potentials (+0.37-+0.05 V vs SCE) coupled with their range of singlet (48-63 kcal mol(-1)) and triplet (48-57 kcal mol(-1)) energies demonstrate that they are potent oxidizing agents in both their singlet and triplet excited states, thermodynamically capable of oxidizing substrates with oxidation potentials as high as 3.1 eV. The pyrylogens are synthesized in three steps from readily available starting materials in modest overall 11.4-22.3% yields. These sensitizers have the added advantages that: (1) their radical cations do not react on the CV timescale with oxygen bypassing the need to run reactions under nitrogen or argon and (2) have long wavelength absorptions between 413 and 523 nm well out of the range where competitive absorbance by most substrates would cause a problem. These new sensitizers do react with water requiring special precautions to operate in a dry reaction environment.

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“…The ratio Φ T /

Φ_{normalT}^{0}

Φ_{normalT}^{0}

= 0.033 ± 0.02, is significantly smaller than that reported for TPP + ,

Φ_{normalT}^{0}

= 0.48 .

[\frac{Φ_{T}}{Φ_{normalT}^{0}} x \frac{Φ_{normalf}^{0}}{Φ_{f}} - 1] {normalΦ}_{T}^{0} = \frac{Φ_{normalf}^{0}}{Φ_{f}} - 1

…”

Section: Resultsmentioning

confidence: 64%

Section: Resultsmentioning

confidence: 99%

Synthesis, Characterization, Photophysics and Photochemistry of Pyrylogen Electron Transfer Sensitizers

Clennan

Liao

2013

Photochem & Photobiology

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“…Using a method of Katritzky et al, [58] base-catalyzed condensation of pyridin-4-carbaldehyde with acetophenone first gave the 1,5-diketone 16, which on treatment with boron trifluorideϪdiethyl ether in acetic acid, in the presence of benzalacetophenone as hydride acceptor, underwent ring closure to give the pyrylium salt 17. [58] Subsequent condensation of 17 with the 4-aminophenol 14 yielded the pyridinium salt 18, which was then Scheme 3. Synthesis of betaine dye 4 with two 2-pyridyl rings in the phenolate part and one 4-pyridyl ring in the pyridinium part Eur.…”

Section: Synthesesmentioning

confidence: 99%

Syntheses and UV/Vis-Spectroscopic Properties of Hydrophilic 2-, 3-, and 4-Pyridyl-Substituted Solvatochromic and Halochromic PyridiniumN-Phenolate Betaine Dyes as New Empirical Solvent Polarity Indicators

et al. 2001

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“…They can be employed as intermediates for the preparation of medicinally active compounds such as those with antimalarial, anticonvulsant and antitumour activities and furthermore in agrochemical active materials such as herbicides, insecticides, desiccants and surfactants . Also, these molecules have been applied for the preparation of organometallic polymers, polyimides,, photoluminescent polymers and chemosensors, and in asymmetric catalysis and supramolecules . Due to the previously mentioned medicinal benefits and applications connected with 2,4,6‐triarylpyridine derivatives, a variety of protocols have been reported for their synthesis …”

Section: Introductionmentioning

confidence: 99%

Catalytic application of sulfonic acid‐functionalized titana‐coated magnetic nanoparticles for the preparation of 1,8‐dioxodecahydroacridines and 2,4,6‐triarylpyridines via anomeric‐based oxidation

Zolfigol

Karimi

Yarie

et al. 2017

Applied Organom Chemis

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We have developed green, efficient and powerful protocols for the preparation of 2,4,6‐triarylpyridines and 1,8‐dioxodecahydroacridines in the presence of Fe3O4@TiO2@O2PO2(CH2)2NHSO3H as a sulfonic acid‐functionalized titana‐coated magnetic nanoparticle catalyst under mild and solvent‐free reaction conditions. These protocols furnished the desired products in short reaction times with good to high yields (20–40 min and 80–86% in the case of 2,4,6‐triarylpyridines; 15–90 min and 80–93% in the case of 1,8‐dioxodecahydroacridines). The final step of the mechanistic route in the synthesis of 2,4,6‐triarylpyridines proceeds via an anomeric‐based oxidation. Also, the nanomagnetic core–shell catalyst can be recycled and reused in both cases of the scrutinized one‐pot multicomponent reactions with high turnover number and turnover frequency.

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Kinetics and mechanisms of nucleophilic displacements with heterocycles as leaving groups. Part 4. 2,4,6-Triaryl-N-benzylpyridinium cations: rate variation with electronic effects in the leaving group

Cited by 19 publications

References 0 publications

Synthesis, Characterization, Photophysics and Photochemistry of Pyrylogen Electron Transfer Sensitizers

Synthesis, Characterization, Photophysics and Photochemistry of Pyrylogen Electron Transfer Sensitizers

Syntheses and UV/Vis-Spectroscopic Properties of Hydrophilic 2-, 3-, and 4-Pyridyl-Substituted Solvatochromic and Halochromic PyridiniumN-Phenolate Betaine Dyes as New Empirical Solvent Polarity Indicators

Catalytic application of sulfonic acid‐functionalized titana‐coated magnetic nanoparticles for the preparation of 1,8‐dioxodecahydroacridines and 2,4,6‐triarylpyridines via anomeric‐based oxidation

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