2516-72-5Relevant academic research and scientific papers
Covalent Organic Frameworks toward Diverse Photocatalytic Aerobic Oxidations
Liu, Shuyang,Tian, Miao,Bu, Xiubin,Tian, Hua,Yang, Xiaobo
supporting information, p. 7738 - 7744 (2021/05/07)
Photoactive two-dimensional covalent organic frameworks (2D-COFs) have become promising heterogenous photocatalysts in visible-light-driven organic transformations. Herein, a visible-light-driven selective aerobic oxidation of various small organic molecules by using 2D-COFs as the photocatalyst was developed. In this protocol, due to the remarkable photocatalytic capability of hydrazone-based 2D-COF-1 on molecular oxygen activation, a wide range of amides, quinolones, heterocyclic compounds, and sulfoxides were obtained with high efficiency and excellent functional group tolerance under very mild reaction conditions. Furthermore, benefiting from the inherent advantage of heterogenous photocatalysis, prominent sustainability and easy photocatalyst recyclability, a drug molecule (modafinil) and an oxidized mustard gas simulant (2-chloroethyl ethyl sulfoxide) were selectively and easily obtained in scale-up reactions. Mechanistic investigations were conducted using radical quenching experiments and in situ ESR spectroscopy, all corroborating the proposed role of 2D-COF-1 in photocatalytic cycle.
Kinetic and thermodynamic control of pseudobase formation from C-3 substituted 1-methylquinolinium cations
Bunting, John W.,Fitzgerald, Norman P.
, p. 1301 - 1307 (2007/10/02)
The kinetic and thermodynamic control of pseudobase formation from 3-W-1-methylquinolinium cations has been studied for a variety of substituents (W).Spectral data indicate that, in both aqueous and methanolic solution, the C-2 pseudobases predominate at equilibrium for W=H and Br, while the C-4 pseudobases are thermodynamically preferred species for W=CONH2, CO2CH3, CN, and NO2.Stopped-flow studies indicate that in all cases the C-2 pseudobases are the kinetically-controlled products upon basification of the aqueous solutions of these cations.Equilibrium constants (pKR+) have been measured for pseudobase formation at both C-2 and C-4 for each W in all cases where they are experimentally accessible.Substituent effects upon pK2R+ correlate with ?m for W, while pK4R+ depends upon ?-p.These substituent effects allow the prediction of pK2R+ = 15.4 and pK4R+ = 17.4 for the 1-methylquinolinium cation.Rates of C-2 to C-4 pseudobase equilibration have been measured in all cases where the latter species is thermodinamically more stable.These kinetic data allow the evaluation of rate constants for C-4 pseudobase equilibration with each cation.In all cases except W=CN, C-2 pseudobase formation is complete within the mixing time of the stopped-flow instrument.
