光敏离子载体丹磺酰基-单氮杂-18-冠-6的阳离子识别性质研究

Cation Recognition of Luminescent Ionophore-dansyl-monoaza-18-crown-6

以 DNS-MAC( O5)为主体 ,利用其荧光性质研究了该物质在乙腈和水溶液中对阳离子 Li+ ,Na+ ,K+ ,Mg2 + ,Ba2 +和 Pb2 +的识别性质 ,由改进的 B-H方程计算了主 -客体配合物的稳定常数和识别敏感因子 .结果表明 ,阳离子的电荷密度和阳离子与冠醚环空间的匹配程度是影响其识别性质的最重要的两个因素 .DNS-MAC( O5)与阳离子配位时荧光光谱的变化主要受控于阳离子的电荷密度 .阳离子与 DNS-MAC( O5)配位时不仅使这种离子载体的偶极矩增大 ,而且更有利于其实现光诱导分子内的电荷转移 ,所以激发态稳定性增加 ,荧光光谱红移 .

Using the title ionophore DNS MAC(O 5) as the host, its cation recognition properties for Li +, Na +, K +, Mg 2+ , Ba 2+ and Pb 2+ in acetonitrile and in aqueous solution were studied by fluorescence and NP RTP method, respectively. The corresponding stability constants and the recognition sensitive factors for the host guest complexes were determined. The results proved that the charge of guest cation and the spatial matching requirement between azacrown ring and the cation are the two most important factors on the recognition process. DNS MAC(O 5) undergoes obviously a spectral change upon binding with cation. These changes are mainly controlled by the charge density of the cation. When the azacrown ether moiety of the ionophore was coordinated with a cation, not only the dipole moment of the lumino ionophore was increased, but also it was more favorable for the photoinduced intramolecular charge transfer, so the stability of exited state was increased and the fluorescence spectrum was red shifted. At the same time, the relative fluorescence quantum of DNS MAC(O 5) in water and acetonitrile was determined by the comparative method in this paper.