Synthesis and sensing behavior of cyanoanthracene modified 1,3-alternate calix[4]benzocrown-6: a new class of Cs+ selective optical sensors
作者:Hai-Feng Ji、Reza Dabestani、Gilbert M. Brown、Robert L. Hettich
DOI:10.1039/b007507h
日期:——
1,3-Calix[4]bis(10-cyano-9-anthrylmethyl-o-benzocrown-6), AnCN2, and 1,3-calix[4]-25,27-bis(allyloxy)-26,28-(10-cyano-9-anthrylmethyl-o-benzocrown-6), AnCN1, were synthesized as the first generation of Cs+ selective optical sensors based on calixarenes. The maximum enhancement in the emission of AnCN2 and AnCN1 upon Cs+ complexation was 11.7 and 8.2 in a 1 ∶ 1 CH2Cl2–MeOH mixture. Their response to various alkali metal ions follows the order Cs+ > Rb+ ≫ K+ ≫ Na+ > Li+ indicating good selectivity towards caesium. The fluorescence and absorption profile for Cs+ complexation suggest a 1 ∶ 1 stoichiometry for the host AnCN1–Cs complex and a stability constant of 107 M−1. AnCN2, on the other hand, shows two plateau regions corresponding to a 1 ∶ 2 stoichiometry for complexation of Cs+. The first complexation constant is much higher (107 M−1) than the second one (104 M−1). The NMR studies further substantiate the complexation of two metal ions by AnCN2. This is the first report of stepwise complexation of metal ions to a 1,3-alternate calix[4]bis(crown-6) derivative.
我们合成了 1,3-Calix[4]bis(10-cyano-9-anthrylmethyl-o-benzocrown-6), AnCN2 和 1,3-Calix[4]-25,27-bis(allyloxy)-26,28-(10-cyano-9-anthrylmethyl-o-benzocrown-6), AnCN1,它们是第一代基于钙钛矿的 Cs+ 选择性光学传感器。在 1 ∶ 1 CH2Cl2-MeOH 混合物中,AnCN2 和 AnCN1 在络合 Cs+ 时的最大发射增强分别为 11.7 和 8.2。它们对各种碱金属离子的反应顺序为 Cs+ > Rb+ ≫ K+ ≫ Na+ > Li+,这表明它们对铯具有良好的选择性。Cs+ 复合物的荧光和吸收曲线表明,宿主 AnCN1-Cs 复合物的化学计量为 1 ∶ 1,稳定常数为 107 M-1。另一方面,AnCN2 显示出两个高原区,对应于 Cs+ 复合物的 1 ∶ 2 化学计量。第一个络合常数(107 M-1)远高于第二个(104 M-1)。核磁共振研究进一步证实了 AnCN2 对两种金属离子的络合作用。这是首次报道金属离子与 1,3-互变钙[4]双(冠-6)衍生物的逐步络合。