Ankur Kanti Guha

Structural, electronic and reactivity studies on group 15 analogues of N-heterocyclic carbene

The present article reports density functional studies on the Group 15 analogues of N-heterocyclic carbene (NHC) on their structure, reactivity, stability and ligating properties. Long-range corrected density functionals have been used due to its recent success in predicting orbital energies. These ligands are found to have greater π-accepting ability than NHC. Electron-donating substituents have a dramatic effect on their stability as well as ligating properties. Furthermore, natural resonance theory (NRT) calculations have been performed to determine the percentage weighting of resonance contributing structures. In addition, density-based global reactivity descriptors such as chemical potential, hardness, electrophilicity index and softness are calculated using four different density functional methods, and compared with CCSD(T) results. Moreover, the density-based local reactivity descriptors are employed to study the reactivity of Group 15 analogues. From the plot of dual descriptors, it is found that the “ene” centre of the Group 15 analogues of NHC is pseudodual.

A theoretical study on antioxidant activity of ferulic acid and its ester derivatives

Phenolic compounds play a very crucial role as antioxidant that can prevent various diseases caused by free radicals in human body. Although, lots of natural phenolic compounds having antioxidant activity are available nowadays, the modeling of compounds with naturally available phenolics as building blocks is very important in order to get enhanced antioxidant activity. In this study, Ferulic acid (FA), one natural phenolic acid present in coffee, apples, orange, etc., is taken as building block and its ester derivatives with different alkyl groups are subjected to measure the antioxidant activity by using density functional theory (DFT). Various parameters like bond dissociation enthalpy (BDE), vertical ionization potential (IPv), reactivity descriptors, metal chelation ability, etc. are used to measure the antioxidant activity. All the parameters suggest that the ester derivatives are superior antioxidants to the parent FA. Since FA has been reported to be present as esters in many herbs and plants, hence our study provides a route to study the structure activity relationship of this class of natural phenolics with antioxidant activity.