Bond Characterization of N,N''-bis(4-pyridylmethyl)oxalamide and trans-4,4''-azo-1,2,4-triazole─A Combined Experimental and Theoretical Charge Density Study

• Main Authors: Wen-Chun Chung, 仲文君
• Other Authors: Yu Wang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/45070165024130577175

碩士 === 國立臺灣大學 === 化學研究所 === 100 === A combined study of experimental and theoretical charge density (CD) are performed on two organic molecules, N,N''-bis(4-pyridylmethyl) oxalamide (4py-ox, C14H14N4O2) and trans-4,4''-azo-1,2,4-triazole (atrz, C4H4N8). The experimental data is collected at 100 K using high resolution single-crystal X-ray diffraction. The molecular structures of these two compounds have inversion center locating at middle of molecules. The former, two pyridylmethyl fragments are connected by an oxalamide group. Adjacent molecules are then linked through intermolecular N–H...N and C–H...O hydrogen bonds. The later is a planar molecule which two triazole five-member rings are connected by an azo group. Two weak C–H...N hydrogen bonds and strong pi–pi interaction with the inter-planar distance of 3.17 Å are observed. Electron densities are depicted via deformation density and Laplacian distribution. The deformation density shows significant charge accumulation in all covalent bonding regions. The Laplacian distribution applies good agreement with VSEPR concept. The bond characterization of intra- and intermolecular interactions are discussed in terms of topological properties. According to the results, the covalent bond character of C–N, C–C, C–O, and N–N bonds are well described in terms of electron density (rhoBCP) and total energy density (HBCP) at the bond critical points. The BCP position of C–O bond clearly indicates polarization character. All the intermolecular interactions including the hydrogen bonding interactions as well as strong pi–pi interaction are allocated through the BCP and the associated bond paths (BPs).