The binding properties of triptycene-derived oxacalixarenes containing 1,8-naphthyridine subunits 1a and 1b toward metal ions were investigated in detail by spectroscopic methods. A couple of new N,O-bridged diazadioxacalixarenes 2a, 2b were synthesized and their binding properties to metal ions were also evaluated. The results showed that the oxacalixarene 1a, a cis-isomer with a boat-like 1,3-alternate conformation and a symmetrical cavity structure, exhibited a highly selective fluorescence response toward Hg2+ ions, while 1b, 2a and 2b did not show selective response towards any specific metal ions. Such selectivity can thus be controlled by the bridging heteroatoms and cavity structures of the macrocycles. Moreover, it was found that the fluorescence of 1a was considerably quenched upon the addition of Hg2+, and a 1 : 2 stoichiometry host–guest complex was proposed on the basis of the Job plot and 1H NMR titrations.
通过光谱学方法详细研究了含有
1,8-萘啶亚基1a和1b的三
联苯衍生的氧杂杯
芳烃对
金属离子的结合特性。合成了几种新的N,O桥联二氮杂氧杂杯
芳烃2a,2b,并评估了它们对
金属离子的结合特性。结果表明,氧杂杯
芳烃1a是一种具有船形1,3交替构象和对称空腔结构的顺式异构体,对Hg2+离子表现出高度选择性的荧光响应,而1b、2a和2b对任何特定
金属离子均未表现出选择性响应。因此,这种选择性可以通过大环的桥联杂原子和空腔结构来控制。此外,发现1a的荧光在添加Hg2+后显着淬灭,并根据Job图和1H NMR滴定提出了1:2的
化学计量主客体复合物。