Gold nanoparticles green synthesis with clove oil: spectroscopic and theoretical study

Certain limitations of obtaining metal nanoparticles with the use of synthetic chemicals have sparked a great interest in scientists to develop green synthesis procedures which use non-toxic and eco-friendly reagents and wastes. Essential oils have the potential to simultaneously act as reducing agents and stabilizers for the synthesis of metal nanoparticles. In the present work, we have synthesized gold nanoparticles (AuNPs) using clove oil (Syzygium aromaticum L. essential oil) as the main reducing agent and stabilizer. The AuNPs solutions were characterized by UV-VIS spectroscopy, and the isolated solid AuNPs were analyzed by Fourier transformed infrared spectroscopy. Various reactivity descriptors determined in terms of Conceptual Density Functional Theory, for the 16 predominant components of clove oil, have been calculated by using the quantum chemical B3LYP/6-311G** level of theory. With the aim to validate the chosen theoretical method, the calculated infrared spectra have been compared with the available experimental spectra. Moreover, the active centers for nucleophilic and electrophilic attacks have been identified through the analysis of atomic partial charges and Fukui function indices. The obtained theoretical results should be considered as a starting point for the prediction of the appropriateness of essential oils for the direct green synthesis of metal nanostructures.