Rosa Indica flower petal anthocyanin mediated biogenic synthesis of PdNPs: Catalyst intended for the Suzuki-Miyaura reactions

In the present work, the Rosa Indica flower petals anthocyanin extract has been employed as a "green" natural source for the synthesis and topping of noble metal nanoparticles [palladium nanoparticles (PdNPs)]. The Rosa Indica flower petals anthocyanin extract effectively replaces the toxic chemicals and stabilizers. The formed PdNPs were exposed to their structural properties examination by the Ultraviolet-Visible absorption, Energydispersive X- ray and Fourier Transform Infrared spectroscopic analysis. The diffraction pattern of the PdNPs@ rose-anthocyanin to the X-ray recognizes their crystalline nature. In addition, the detailed analysis of the X-ray pattern and microscopic images of FESEM, TEM reveals that formed PdNP@ rose-anthocyanin possesses FCC crystal lattice with average dimensions of the particle - 12 nm. The EDS analysis shows that the PdNPs@ rose-anthocyanin contains - 80 wt% PdNPs. Further, the PdNP@ rose-anthocyanin were efficiently catalyses the Suzuki-Miyaura cross-coupling (C-C) reactions between an aryl halide and phenylboronic acid in the presence of K2CO3 as a suitable base. To catalyse the reaction, PdNPs@ rose-anthocyanin works as heterogeneous catalyst in the absence of heating. Moreover, it provides a good to high yield of the corresponding coupled products under aerobic conditions with optimum reaction time in the aqueous medium, particularly at room temperature with a virtuous Turnover number relative to several synthesized PdNPs. Further, the catalyst PdNP@ rose-anthocyanin shows righteous catalytic activity without significant loss in its efficiency up to four reusable cycles.