Mixed NHC-thiolato complexes of palladium: understanding the formation of di- mononuclear complexes.

The preference for the formation of mono- dinuclear mixed carbene/thiolato complexes of Pd has been studied with three types of N-heterocyclic carbenes derived from benzimidazole, imidazole and 1,2,4-triazole. The complexes were prepared by treatment of halido/NHC precursors with sodium isopropylthiolate in a salt metathesis reaction. Mononuclear complexes are formed when the sulfur and carbon donors are exclusively to each other, while their arrangement preferably leads to dinuclear complexes with μ-bridging thiolato ligands.

Flavonoid loaded nanoparticles as an effective measure to combat oxidative stress in Ribonuclease A.

Flavonoids like quercetin and myricetin serve as naturally occurring antioxidants but their bioactivity is limited due to low aqueous solubility and oxidation under physiological conditions. In this current study, the antioxidant activity of quercetin and myricetin loaded chitosan nanoparticles during the induced oxidation of Ribonuclease A (RNase A) has been compared with the corresponding free flavonoids. Oxidation of RNase A leads to intermolecular dityrosine (DT) bond formation which shows a characteristic fluorescence emission around 405 nm.