A theoretical study of the photochromic mechanism of a novel photochromic compound: 1-phenyl-3-methyl-4-(4-bromobenzal) pyrazolone-5 thiosemicarbazone

作者：Guo Y; Liu GF; Liu L; Jia DZ^*

来源：Journal of Molecular Structure (Theochem), 2004, 712(1-3): 223-231.

DOI：10.1016/j.theochem.2004.10.031

• DFT
• AM1
• photochromism
• molecular orbital
• conformation
• NBO charge
• crystal structure
• hydrogen bond

Semi-empirical AM1 method and DFT method (B3LYP/6-31G*) are used to investigate the photochromic mechanism of 1-phenyl-3-methyl-4-(4-bromobenzal) pyrazolone-5 thiosemicarbazone. The title compound is photochromic and non-planar. Intermolecular hydrogen bonds are observed between the pairs of atoms O and N(5) [2.853(3) Angstrom], O and N(8) [2.957(4) Angstrom]. The H atom is essentially bonded to the N atom. The crystal structure of the title compound is optimized and characterized as the minima of the potential energy surface at AM I level and DFT (B3LYP/6-31G*) level, respectively. NBO charge distribution, conformation and HOMO and LUMO molecular orbitals are analyzed using the results calculated at B3LYP/6-31G* level. The results can well explain these experimental phenomena and indicate that the title compound';s photochromic mechanism is the function of conformation, charge and orbital. The work is helpful to further study the photochromic intermolecular proton transfer mechanism.

• 出版日期2004-12-31
• 单位中国科学院长春应用化学研究所; 新疆大学