A charge density study of pi-delocalization and intermolecular interactions

作者：Wu, L. -C.; Chung, W. -C.; Wang, C. -C.^*; Lee, G. -H.; Lu, S. -I.; Wang, Y.

来源：Physical Chemistry Chemical Physics, 2015, 17(21): 14177-14184.

DOI：10.1039/c5cp01575h

• CENTER-DOT-O
• X-RAY-DIFFRACTION
• THEORETICAL ELECTRON-DENSITY
• TRANSITION-METAL COMPOUNDS
• AVERAGED FERMI HOLES
• BOND CHARACTERIZATION
• HYDROGEN-BOND
• COORDINATION POLYMER
• MOLECULAR-CRYSTALS
• STACKING INTERACTIONS

The compound trans-4,4'-azo-1,2,4-triazole (atrz) is a planar molecule with two planar triazole rings bridged by an azo group. The molecule is a good donor ligand and has an interesting pi-delocalized character. In addition, intermolecular interactions in the crystalline state through pi-pi stacking are found between triazole rings with a very short inter-planar distance of 3.17 angstrom. The electron density distribution is obtained from both high resolution X-ray diffraction data at 100 K and density functional theory (DFT) calculations using the omega B97X-D functional. Bond characterization is performed in terms of the charge density distribution and the associated topological properties. The Laplacian distribution around each atom reveals the shape of the valence-shell charge concentration and demonstrates a sp(2) hybrid orbital shape for each atom in the molecule. The pi-delocalization of the planar molecule is further illustrated by the Fermi-hole distribution. The weak intermolecular pi-pi interactions and hydrogen bonds are further illustrated by the Hirshfeld surface. The energies of weak intermolecular pi-pi interactions and hydrogen bonds have been calculated using omega B97X-D/6-311++G(3df,2p) at experimental geometry.

• 出版日期2015
• 单位苏州大学