ZnO yarı-iletken nanopartikülleri kullanılarak heterojen fotokataliz sistemi ile azid-alkin çıt-çıt reaksiyonu

In the past decade, selectivity, efficiency and diversity are the most important and required subjects for various reaction systems. "Click chemistry" can be given as an example for these systems offering remarkable advantages. Copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) reactions between azides and terminal alkynes which developed by the groups of Sharpless and Meldal, have become the most popular click reactions to date. These reactions are versatile, regiospecific, and exhibit a high efficiency under mild reaction conditions with little or no by-products. Although there are a variety of metals that can be used as a catalyst for the azide-alkyne cycloaddition reactions, copper stands out as the only metal for the reliable, simple, fast and 1,4-regiospecific catalysis. With all these excellent features, CuAAC has found precious applications in different fields such as drug discovery, biochemistry, polymer chemistry and materials science. Recently, there is an explosive growth of research in the field of nanomaterials due to their operation for materials and devices using different techniques at nanometer scale. Nanoparticles are a part of nanomaterials that are defined as a single particles 1–100 nm in diameter and they have been a common material to develop new cutting-edge applications in communications, energy storage, optics, transmission, environmental protection, cosmetics, biology, and medicine due to their attractive optical, electrical, and magnetic properties. Moreover, nanoparticles can be combined with a wide range of metals and semiconductor core materials that bring in advantageous properties such as fluorescence and magnetic treatment. Amongs all the various types, zinc oxide - semiconductor metal oxide nanoparticles- are the most preferred type with their own importance due to their vast area of applications, such as, gas sensor, chemical sensor, bio-sensor, cosmetics, storage, optical and electrical devices, solar cells, and drug-delivery. In this thesis, a visible light-induced copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) strategy is carried out benefiting from the electron transfer reactions of zinc oxide nanoparticles (ZnO NPs) to achieve the required catalyst for the coupling process. Semiconductor ZnO NPs as a heterogeneous photocatalyst releases electrons on UV/VIS irradiation resuting in the photoreduction of air-stable copper(II) ions to copper(I) which is the catalyst of the CuAAC reaction A variety of azide and alkyne components has been examined and the system tolerates different substrates in the click reaction well. 1H-NMR and FTIR spectroscopy are used for the characterization of the reactions and it was determined that a triazole forms with the consumption of the starting azide and alkyne molecules.