Complex nanoconjugate materials obtained from eco-friendly gold and silver nanoparticles and zinc phthalocyanine derivatives

This paper presents the biosynthesis of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) from three different plants with numerous pharmacological benefits: Elderflower (Sambucus nigra L.), Acacia (Robinia pseudacacia L.) and Cornflower (Centaurea cyanus) and also describes the chemical synthesis of two phthalocyanine derivatives: tetracarboxamido-zinc phthalocyanine ZnPc(CONH2)(4) and octacarboxamido-zinc phthalocyanine ZnPc(CONH2)(8), their physical - chemical characterization (e.g.: UV-Vis, FTIR) and the quantum yield of singlet oxygen generation. All the aqueous extracts are characterized by means of qualitative (e.g.: saponins, steroids, terpenoids, antraquinones, cardiac and anthraquinone glycosides, etc.) and quantitative (e.g.: total content of flavonoids, total content of terpenoids, total content of polyphenols, etc.) phytochemical screening using standard analytical methods and the results clearly show the presence of different bioactive compounds that play a key role in the reduction of metal ions to nanoparticles. Antioxidant activity of both aqueous extracts and metalic nanoparticles is measured and the formation of both metalic nanoparticles is confirmed by optical microscopy (OM) images. The easiest way to observe the formation of AgNPs and AuNPs is the visual change in color of the plant extract solutions which is then confirmed by recording the UV-Vis spectra. Biosynthesized silver and gold nanoparticles are compared to those obtained by classic chemical synthesis. AgNPs and AuNPs further react, for 96 hours and under constant stirring at room temperature, with the two Pcs to obtain complex nanoaggregate materials whose potential formation is analyzed by means of spectroscopic investigations (e.g.: UV-Vis, FTIR, DLS).