Development of Novel Photo-responsive Compounds with Multi Molecular Recognition Sites

本文研究了新型光响应宿主分子对碱金属和碱土金属阳离子的选择性识别。通过这项工作得到的结果总结如下：1)合成了两种两侧臂端各有芘基团的双臂链醚，并利用荧光光谱研究了它们对碱金属和碱土金属阳离子的络合性能。金属离子络合后，芘准分子发射降低，单体发射增加。这一发现是由于与金属阳离子络合作用抑制了两个芘环的冠环和两个侧臂中的一个的运动，从而改变了两个芘环的空间距离。碱土金属阳离子的选择性高度依赖于宿主腔的适合度和客体尺寸。2)描述了一种新型含芘环的单氮型荧光指示剂及其荧光特性，考察了水中碱金属和碱土金属阳离子存在时的荧光特性。基于PET机制，通过改变宿主化合物的荧光强度来检测金属阳离子。在水溶液中，由于Ba^<2+>与Ba^<2+>的络合能力非常弱，所以加入Ba^<2+>后荧光团的荧光性很小，但Triton X-100胶束的共存使得荧光团对Ba^<2+>的检测具有很高的灵敏度和选择性。此外，利用单氮代荧光团与Ba^<2+>之间的络合行为作为一种新的芘功能化探针来测定CMC。将PET法测定的CMC值与DPH、ANS、芘探针等常规荧光法测定的CMC值及文献值进行比较，发现PET法可用于测定各种非离子和阴离子表面活性剂的CMC值，也可用于测定CMC值较低的非离子表面活性剂的CMC值，且比其他荧光法更有效。这一显著的成就可能是由于芘环的高灵敏度，探针对芘的高溶解度（由于存在隐位功能），以及基于PET机制的荧光强度的剧烈变化

This research deals with the selective discrimination of alkali metal and alkaline earth metal cations by novel photo-responsive host molecules. -The results obtained through this work are summarized as follows.1)Two types of double-armed lariat ethers with pyrene moieties at each end of two sidearms were synthesized and their complexation properties toward alkali metal and alkaline earth metal cations were examined by fluorescence spectroscopy. Pyrene excimer emission decreased accompanied by an increase in monomer emission upon metal ion complexation. This finding is ascribed to the change of the spatial distance of two pyrene rings by movement suppression of both the crown ring and one of the two sidearms based on complexation with the metal cation The selectivity for alkaline earth metal cations was highly dependent on the fitness of the host cavity and the guest size.2)Novel monoazacryptand-type fluorescent indicators with a pyrene ring were described and their fluorescent charact … More eristics in the presence of alkali metal and alkaline earth metal cations in waterwere examined. The detection of metal cations was performed by the change of the fluorescence intensity of host compounds based on PET mechanism. In aqueous solution, the fluorophore showed little fluorescence upon the addition of Ba^<2+> because of the very weak complexation ability with Ba^<2+>, but the coexistence of Triton X-100 micelles enabled the fluorophore to detect Ba^<2+> with very high sensitivity and selectivity. Moreover, the complexation behavior between the monoazacryptand-type fluorophore and Ba^<2+> was utilized as anew pyrene-functionalized probe for CMC determination. From a comparison of the CMC values obtained by the PET method versus the CMC values obtained by conventional fluorescent methods utilizing DPH, ANS and pyrene probes as well as the literature values, one can conclude that this PET method was useful for the CMC determination of various nonionic and anionic surfactants, and for the CMC determination of nonionic surfactants with arvery low CMC, and was more effective than any other fluorescent method. This notable achievement may be due to the high sensitivity of the pyrene ring, the higher solubility of the probe (due to the presence of the cryptand functionality) over pyrene, and a drastic change in the fluorescence intensity based on the PET mechanism Less