We report the detection of Cu(II) and NO at micro and nano-molar concentrations, respectively, by poly(aryl ether) dendron derivatives containing anthracene moiety attached through an acylhydrazone âmolecular loopâ. In the absence of Cu(II), the acylhydrazone moiety undergoes cisâtrans photo-isomerization, resulting in negligible emission from anthracene. Conversely, specific binding of Cu(II) by the acylhydrazone unit arrests the isomerization process and triggers aggregation of the molecules through hydrogen bonding and ÏâÏ interactions. The metal ion driven self-assembly leads to significant enhancement of the emission intensity from the anthracene excimer with a dendritic effect on the emission quantum yield (maximum Φexcimer emis. â¼0.11 ± 0.01). The binding constants (log K) for the 1â:â1 complexes between the dendron derivatives and Cu(II) were determined using a fluorescence titration method and the values fall between 9.13 and 10.16. The Cu(II)âdendron systems were then exposed to nitric oxide (NO) along with other gases and the systems exhibit specific fluorescent âoffâ signal towards NO at nano-molar concentrations. The mechanism of quenching was analyzed and the results suggest that the presence of NO leads to de-aggregation in the system.
我们报告了通过酰基腙 "分子环 "连接的含有
蒽分子的聚(芳基醚)树枝状衍
生物在微摩尔和纳米摩尔浓度下分别检测
铜(II)和氮氧化物的情况。在没有 Cu(II)的情况下,酰基腙会发生顺反光异构化,从而导致
蒽的发射微乎其微。相反,Cu(II)与酰基腙单元的特异性结合会阻止异构化过程,并通过氢键和ÏâÏ相互作用引发分子聚集。
金属离子驱动的自组装显著增强了
蒽准分子的发射强度,并对发射量子产率产生了树枝状效应(最大δ准分子发射率为0.11±0.01)。利用荧光滴定法测定了树枝状衍
生物与Cu(II)之间1:â1复合物的结合常数(log K),其值介于9.13和10.16之间。然后将 Cu(II)-树枝膦系统与其他气体一起暴露于
一氧化氮(NO)中,在纳米摩尔浓度下,系统对 NO 显示出特定的荧光 "熄灭 "信号。对淬灭机制进行了分析,结果表明
一氧化氮的存在导致了体系的去聚集。