ABSTRACT
Weak molecular forces are important in controlling the three-dimensional structure of proteins and nucleic acids and play vital roles in regulating biochemical processes. Among noncovalent molecular forces, the hydrogen bond1 is one of the most abundant, and its energy is within the range of 3 to 7 kcal/mol. In the conventional hydrogen bond, Coulomb energy is the most important energy source because this is the interaction between a hard acid (HA) and a hard base (HB) in the context of the Pearson hard soft acid base (HSAB) principle.
