Cu2O modified g-C3N4 as an effective catalyst for the synthesis of propargylamines: experimental, quantum mechanical mechanistic and kinetic study
In this research, graphite-like carbon nitride (g-C3N4) was prepared via a common method i.e. one-step thermal polycondensation of urea and then modified by copper (I) oxide. After that, the as-prepared g-C3N4/Cu2O composite was used as the superior catalyst for effective coupling reaction between arylaldehydes, alkynes and secondary amines in the formation of wide range of propargylamine derivatives. The new, efficient catalyst was characterized using different techniques including Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The reactions were performed in nearly low reaction times, and the products were obtained in moderate to high yields. At the end of the transformation, using by simple filtration, the catalyst was separated from reaction mixture and reused for four times with minimum loss of activity. The catalyst is simple to prepare and shows higher catalytic activity than some recently reported catalysts. Moreover, the potential energy surface (PES) of the reaction has been studied by density functional theory (DFT) and it was realized that the first step of the reaction, that is, separation of acetylenic hydrogen shows a primary kinetic isotope effect and hence is the rate determining step of the reaction.
KeywordsGraphitic carbon nitride Propargylamine DFT study Mechanism Potential energy surface
The authors gratefully acknowledge Semnan University Research Council for financial support of this work.
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Conflict of interest
The authors declare that they have no conflict of interest.
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