Quantum Chemistry Calculation of Substituent Effect on Intermolecular Interaction of Amide Molecules and Intermolecular Interaction of Polypeptide

• Main Authors: Zhi-Yong Zeng, 曾志踴
• Other Authors: 趙聖德
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/99897531186244430267

碩士 === 國立臺灣大學 === 應用力學研究所 === 103 === The first part of this research is studying the N-H...O=C type hydrogen bond by substitution alkyl groups on amide molecules. All the quantum chemistry calculations were performed at the wB97XD/aug-cc-pVDZ using the Gaussian 09 program to calculate the intermolecular interaction of formamide dimer, acetamide dimer, propioamide dimer, N-methylformamide dimer, N-methylacetamide dimer, N-methylpropionamide dimer. In addition, PSI4 software was utilized through SAPT method to decompose the intermolecular interaction into four parts, as electrostatic energy; induction energy; dispersion energy; exchange energy, to discuss the alkyl groups how to influence N-H...O=C type hydrogen bond. The second part is simulating the intermolecular interaction of beta-sheet structure. The method wB97XD/6-31+G* was used to optimize the structure and calculate the intermolecular interaction of antiparallel beta-sheet structure. In this part, we focus on the intramolecular hydrogen bond and intermolecular hydrogen bond of of beta-sheet structure. We also have carried out the vibrational spectrum of formamide, acetamide and propionamide through harmonic and anharmonic model. IR spectrum calculated by monomers can obtain the functional group. When comparing the vibrational spectrum of the monomer and dimer, we can find the red shift of frequencies due to hydrogen bond. And compare with the experiment, we can confirm our simulation spectrum.