دانلود گزارش کارورزی و کار آموزی

چکیده :

Elongation of the conjugated chain of resveratrol has been proved to be an effective strategy to further

improve its antioxidative capacity and radical scavenging ability. In this work, quantum chemical calculations

based on density functional theory have been employed at B3LYP/6-311G(d,p) level of theory to

study the influence of the conjugated chain length on equilibrium geometries and properties of relevant

species. Our results show elongation of conjugated chain significantly decreases 40-OH bond dissociation

enthalpy (BDE), ionization potential (IP) and proton affinities (PAs) of phenolate ions in gas phase. In

aqueous solution 40-OH BDE, IP are lower as compared to that in gas phase, for PAs of phenolate ions

almost no change is induced, but significant decrease in electron transfer enthalpy (ETE) is presented.

These indicate that longer conjugated chain is favorable for the radical scavenging capacity and antioxidative

activity. In addition, stable s-cis conformers of long chain reservatrol analogs are found to be more

favorable for production of phenoxyl radicals and cation radicals as compared to trans conformers, with

concomitant enhancement of the antioxidative activity