Density functional theory study on the interaction between formamide and adenine

Abstract

The hydrogen bonding of complexes formed between formamide and adenine molecules has been investigated using density functional theory method at 6-311++G(d, p) level. Nine stable cyclic structures with two hydrogen bonds being involved in the interaction have been found on the potential energy surface. According to the different hydrogen donors offered by formamide molecules, the nine complexes can be divided into two groups. For AF1-AF5, the hydrogen donors are carbon atoms of the formamide molecules, while the nitrogen atoms act as the hydrogen donors in AF6-AF9. The complex AF6 is most stable amongst all the complexes and N8 atom and N9-H15 group form the strongest hydrogen bonds. The hydrogen bonds with the participation of C3-H11 group are the weakest. The vibrational frequency shifts and IR intensities shifts are also reported.