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CuIn-ethylxanthate a a??versatile precursora?? for photosensitization of graphene-quantum dots and nanocatalyzed synthesis of imidazopyridines with ideal green chemistry metrics
摘要： Recently, the development of hybrid nano catalyst involving earth abundant transition metals for photosensitization and multi-component reaction in industry and academia has been a matter of intense study. Such hybridized catalytic systems minimize the production cost and acts as a bridged system by diversifying the application in different areas. In the present study copper indium ethylxanthate was used as a versatile precursor for synthesis of colloidal chalcopyrite phase copper indium sulphide (CC-CIS NPs) in photosensitization of graphene quantum dots and reusable powdered wurzite phased copper indium sulphide nanoparticles (PW-CIS500 NPs) for selective and efficient single pot sustainable synthesis of substituted imidazopyridines via A3 coupling strategy of an aldehyde, amine and alkyne. The material was characterized by various spectroscopic techniques viz HR-TEM, PXRD, FESEM, elemental mapping studies, UV visible spectroscopy, photoluminescence, XPS, BET and ICP-OES/MS etc. Quenching of photoluminescence intensity of colloidal CuInS2 on anchoring the graphene quantum dots (GQDs) was confirmed by photosensitization of GQDs via efficient charge transfer in CIS-GQD interface. On the other hand, the PW-CIS500 NCs catalyzed A3 coupling strategy demonstrates the high catalytic efficiency for A3 coupling reaction giving substituted imidazopyridines without losing its activity and could be recycled with a total turnover number of > 210, good E-factor of 0.13 and high RME of 88%.
关键词： multicomponent reactions,heterogenous catalysis,copper indium sulphide,copper indium ethylxanthate,imidazopyridines,graphene quantum dots,charge transfer
更新于2025-09-23 15:19:57
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Unique Luminescence of Hexagonal Dominant Colloidal Copper Indium Sulphide Quantum Dots in Dispersed Solutions
摘要： Luminescent hexagonal dominant copper indium sulphide (h-dominant ciS) quantum dots (QDs) by precursor-injection of mixed metal-dialkyldithiocarbamate precursors. Owing to the different reactivity of the precursors, this method allowed the ciS QDs to grow while retaining the crystallinity of the hexagonal nucleus. The photoluminescence (PL) spectra exhibited dual emission (600–700 nm red emission and 700–800 nm NIR emission) resulting from the combined contributions of the hexagonal (wurtzite) h-ciS and tetragonal (chalcopyrite) t-ciS QDs, i.e. the niR and red emissions were due to the h-ciS QDs and coexisting t-ciS QDs (weight ratio of h-ciS/t-CIS ~ 10), respectively. The PL intensities of the h-ciS as well as t-ciS QDs were enhanced by post-synthetic heat treatment; the t-ciS QDs were particularly sensitive to the heat treatment. By separating h-ciS and t-ciS successfully, it was demonstrated that this phenomenon was not affected by size and composition but by the donor-acceptor pair states and defect concentration originating from their crystal structure. the h-dominant CIS QDs in this work provide a new technique to control the optical property of Cu-In-S ternary NCs.
关键词： defect states,copper indium sulphide,quantum dots,photoluminescence,crystal structure
更新于2025-09-16 10:30:52