Density Functional Theory Study of Hydrogen Bonding Dimers with 4-Pyridinecarboxylic Acid Hydrazine

The H-bonding dimers of 4-pyridinecarboxylic acid hydrazine were studied using density functional theory (DFT) at B3LYP/6-311++G** level. The results showed that the most stable dimer D1 had two same linear N-H center dot center dot center dot O hydrogen bonds, and the interaction energy between them was 51.038 kJ.mol(-1) which was corrected by the basis set superposition error and zero-point. The stretching vibration frequency of N-H bond had a red shift because of the hydrogen bonds. The natural bond orbital analysis showed that each N-H center dot center dot center dot O hydrogen bond in D1 had the biggest interaction stabilization energy of 69.078 kJ.mol(-1). Thermodynamic analysis indicated that the formation process of D1 was exothermic and spontaneous at low and room temperatures.