DFT Study of conformational flexibilities and interaction profiles of new class of nucleoside analogs having nucleic acid bases pairs (Pyrimidine analogues-Adenine) linked through a 1,2,3-triazole spacer

Abstract

DFT calculations predict the existence of three stable conformations (one opened and two closed conformations) of the new class of nucleoside with various substituents (X = H, CH3, F, Cl, and Br). The calculations predict also that the two closed conformation are stabilized by intramolecular hydrogen bond. The N17–H34 stretching is large red shift by as mush 380–455 cm-1 due to the intramolecular N17–H34…N8 hydrogen bonding. The red shift is accompanied by a large enhancement of the N17–H34 absorption intensity. It shows that these intramolecular hydrogen bonds are classical H–bonds.

Keywords

• red shif
• hydrogen bond
• quantum chemical calculation
• DFT
• conformational analysis
• triazolo-nucleoside