有机光功能材料分子设计研究 Ⅰ.俘精酸酐类光致变色材料量子化学研究

Molecular Design Study of Organic Photo-functional Materials Ⅰ.Quantum Chemical Study on Fulgide Photochromic Materials

用AM1对呋喃基取代的六种俘精酸酐类分子开环体、闭环体基态与激发态的结构进行了优化,所得俘精酸酐1的开环体基态平衡几何结构与已有的实验结果一致.计算结果能较好地解释俘精酸酐的热稳定性和光致变色性能,对取代基对俘精酸酐结构的影响取得了一些新的认识.根据俘精酸酐1开环体上各碳原子的净电荷密度,讨论了它的^(13)CNMR波谱.

In this paper, semi-empirical method AM1 is used to study the relationship between structures and photochromic properties of fulgides. Structures of six kinds of fulgides were optimized. The calculated ground state equilibrium structure of 1E was compared with that of experiment - a and the quantum chemical calculation results of others. Our result indicated that the first singlet excited structures of unclosed and closed fulgides were more similar to eachothe than their ground states, which explained why fulgides were both thermostable and photochromic. The trend of the quantum yield of ring opening (ΦCE) is in agreement with that of bond order of C(10)-C(15) of closure structures of fulgides. However, thequantum yield of ring closure (ΦEC) cannot be interpreted simply in termsof the distance and bond order of C(10) - C ( 1 5 ) . Regarding unclosed fulgides , the reason for the shorter distance between C(10)-C(15) in excited state than that in ground state is believed to be the torsion interaction between furan group and R2. Additionally, carbon atomic net charges of 1E can be used to explain its 13C NMR data.