Green synthesis: The use of brown algae in the synthesis of palladium nanoparticles and their application as catalysts in the synthesis of important pharmaceutical intermediates

Abstract

Environmental awareness and concern have led to the development of green chemistry protocols which aim to mitigate the negative impact of the pharmaceutical industry on the environment. The biaryl ring system is common to a number of active pharmaceutical ingredients (APIs). The aim of the current study is to utilize waste biomass generated during the isolation of seaweed natural products to synthesise “green” palladium nanoparticles (PdNPs) that will be used to catalyze biaryl coupling reactions. Green chemistry is defined as the design of chemical processes and products that reduce or eliminate the generation and use of hazardous substances. This protocol is guided by a set of rules, commonly known as the 12 principles of green chemistry. Many synthetic methods that were used before the development of this protocol made use of toxic reagents and solvents that were harmful or detrimental to the environment. Green chemistry, therefore, makes use of less harmful substances, such as plants, seaweeds, and green reagents and/or solvents. This study will further explain the use of Sargassum incisifolium, a species of brown algae found on the west coast of Southern Africa to synthesize palladium nanoparticles. Two types of extracts- an aqueous extract (AE) and an organic aqueous extract (OAE) were prepared from the seaweed. Before any further use, the extracts were characterized by NMR and UVVisible spectroscopy, and their polyphenolic content, reducing capacity, and radical scavenging ability was determined. Further characterization of the extracts was carried out by FTIR and TGA analyses.