Three homologs of trans-4-stilbenecarboxylic acid, viz., trans-4-stilbeneacetic acid (18), β-(trans-4-stilbene)propionic acid (19), and γ-(trans-4-stilbene)butyric acid (20) were synthesized and, together with the parent trans-4-stilbenecarboxylic acid, used to obtain the corresponding [ω-(trans-4-stilbene)carboxylatoalkylpentaamminecobalt(III) complexes, [(PhCH=CHC6H4(CH2)nCOO)Co(NH3)5]2+ (1-4), where n = 0, 1, 2, or 3. Fluorescence studies suggest that an intramolecular excitation energy transfer occurs from the first excited singlet state of the ligand to the metal giving rise to a charge-transfer triplet-excited state of the complex, based on the analogy with previous work on complex 1. The efficiency of the energy transfer seems to decrease with increasing number of the methylene groups in the ligand.
合成了三种
trans-4-苯基
乙烯羧酸的同源物,即
trans-4-
苯乙酸(
18)、β-(
trans-4-苯基
乙烯)
丙酸(
19)和γ-(
trans-4-苯基
乙烯)
丁酸(
20),并与母体
trans-4-苯基
乙烯羧酸一起用于获得相应的[ω-(
trans-4-苯基
乙烯)
羧酸烷基五胺合
钴(III)配合物,[(PhCH=CHC
6H
4(CH
2)
nCOO)Co(NH
3)
5]
2+ (
1-
4),其中
n= 0、1、2或3。荧光研究表明,从
配体的第一激发单重态到
金属发生了分子内激发能量转移,从而产生了一个荷移三重激发态的配合物,这是基于先前关于配合物
1的工作的类比所得。能量转移的效率似乎随着
配体中亚甲基基团数量的增加而降低。