Theoretical Study On The Hydrogen-bonding Formed By The Side Chain Of Serine Dipeptide And Different Kinds Of Small Molecules

Hydrogen bond plays a significant role in chemistry, life science area and functional material field. So discussing its energy and structure must be much more vital. In our article, we use MP2 method computing the energies, structures and potential energy curves of hydrogen-bonding dimers formed by different small molecules and serine dipeptide. The main task of the research can be reduced to two parts as following:1. We choose four kinds of typical hydrogen bonds in life and biology system:C=O…-O, O…H-O, S…H-O and N…H-O. There are fifteen hydrogen-bonded structures using inner-coordinate to make it clear that just only one hydrogen bond in each dimer. From calculation we can find:The energy of hydrogen bond N…H-O is the lowest one and its hydrogen bond is most stable. When the substituents are the same, the energy of sp3 hybird orbital O atom in acceptor is much more stable than sp2 hybird orbital O atom in acceptor.2. For C=O…H-O hydrogen bond, the small molecules are proton acceptor. When the substituents are electron withdrawing groups, they make the length of C=O and O-H longer. When the substituents are electron donating groups, they make the length of C=O and C-O shorter. Also in S…H-O hydrogen bond and O…H-O hydrogen bond. When the substituents are electron withdrawing groups, they make the length of O-H longer.3. For the fourteen kinds of dimers, we use a new method for computing hydrogen-bonded potential energy curves with the parameters of Sun. Comparing the curves with basis set superposition error, it does well in the potential energy curves with BSSE of C=O…H-O hydrogen-bonding.