Light effect on Click reaction: Role of photonic quantum dot catalyst

Abstract

Due to the light excitation, the valence band electron of the copper (I) sulfide quantum dot transfer to the conduction band and act as a scavenger of the terminal proton of the alkyne in the presence of organic azide with the formation of 1,4-disubstituted 1,2,3-triazoles, where the copper(I) species of Cu2S act as a catalyst for the reaction. The above cycloaddition reaction between alkyne and azide is commonly known as the Click reaction. In this study, experiments were carried out under the exposure of ultra-violate and daylight and also dark environment. According to the original recommendation for the Click reaction, the role of the base was also considered for this experiment. We found that the effect of conduction band electron is more efficient than the recommended conventional base mediated reaction procedure.

Free‐radical‐mediated copper‐catalyzed triazole formation under UV‐irradiation

“…In the spectrum (b), a characteristic peak at 1027 cm −1 represents the vibration of ‐C‐O‐C‐ in MPEG‐doped Cu (I)‐polyaniline. The detailed characterization of the Cu (I)‐polyaniline system is available elsewhere …”

“…Copper serves as a catalyst for the title reaction, whereas MPEG scavenges the free‐radicals with the formation of stable carbon‐centered free‐radicals that abstract the H‐atom from the alkyne molecule by means of a hydrogen atom transfer mechanism, and finally proceed for the triazole product in the presence of an azide molecule. In association with our ongoing research on the fabrication of effective catalysts for the cyclo‐addition of azide and alkyne molecules, further efforts will undertake in future for the development of new materials as catalyst to perform the similar kind of reactions by involving the heterocycle substituted azide molecules.…”

“…In association with our ongoing research on the development of efficient catalysts for the azide‐alkyne cycloaddition reaction, we have found the crucial role of light energy on the yield of the reaction . Due to the light excitation, the conduction band electron of the Cu (I) sulfide quantum dot acts as a scavenger of the terminal proton of the alkyne in the presence of organic azide with the formation of 1,4‐disubstituted 1,2,3‐triazoles, where the Cu (I) species of Cu 2 S acts as a catalyst for the reaction .…”

“…In association with our ongoing research on the development of efficient catalysts for the azide‐alkyne cycloaddition reaction, we have found the crucial role of light energy on the yield of the reaction . Due to the light excitation, the conduction band electron of the Cu (I) sulfide quantum dot acts as a scavenger of the terminal proton of the alkyne in the presence of organic azide with the formation of 1,4‐disubstituted 1,2,3‐triazoles, where the Cu (I) species of Cu 2 S acts as a catalyst for the reaction . We also have demonstrated that the composite of copper nanoparticles and carbon nitride performs as an effective system for the cycloaddition reaction between azide and alkyne molecules under UV‐radiation conditions where copper nanoparticles serve as active catalyst and the photoactive support material (carbon nitride) plays the role of a promoter …”

A Cu(II)‐Inorganic Co−Crystal as a Versatile Catalyst Towards ‘Click’ Chemistry for Synthesis of 1,2,3‐triazoles and β‐hydroxy‐1,2,3‐triazoles

“…Luz et al showed Copper catalyzed ‘click’ reaction by benzyl azide as substrate . Nandi and co‐workers also showed the Copper catalyzed ‘click’ reaction . Besides, the synthesis of β‐hydroxy‐1,2,3‐triazoles has also been performed through ‘click’ reaction by the use of suitable epoxides with CuSO 4 or CuI .…”