Revisiting the photophysical properties and excited singlet-state dipole moments of several coumarin derivatives
作者:Lamine Cisse、Abdoulaye Djande、Martine Capo-Chichi、François Delatre、Adama Saba、Alphonse Tine、Jean-Jacques Aaron
DOI:10.1016/j.saa.2011.02.053
日期:2011.8
by various solvatochromic methods, using the theoretical ground-state dipole moments which were calculated by the AM1 method. The first excited singlet-state dipole moment values were obtained by the Bakhshiev, Kawski–Chamma–Viallet, Lippert–Mataga, and Reichardt–Dimroth equations, and were compared to the ground-state dipole moments. In all cases, the dipole moments were found to be higher in the excited
溶剂对几种香豆素衍生物的电子吸收和荧光发射光谱的影响,这些香豆素衍生物在7、4位含有氨基,N,N-二甲基-氨基,N,N-二乙基-氨基,羟基,甲基,羧基或卤素取代基,或3,在具有不同极性的八种溶剂中进行了研究。这些香豆素的第一激发单重态偶极矩是通过各种溶剂变色方法,使用通过AM1方法计算的理论基态偶极矩来确定的。通过Bakhshiev,Kawski–Chamma–Viallet,Lippert–Mataga和Reichardt–Dimroth方程获得了第一个激发的单重态偶极矩值,并将其与基态偶极矩进行了比较。在所有情况下,由于两种态的电子密度不同,激发单重态中的偶极矩比基态中的高。大多数化合物在增加溶剂极性时观察到吸收带和荧光发射带的红移,表明电子跃迁具有π–π *性质。