A benzimidazole appended triazole linked 1,3-diconjugate of calix[4]arene (L) has been synthesized and characterized. The conjugate L has been found to recognize Cu2+ among the thirteen different metal ions studied by exhibiting ratiometric fluorescence changes through newly generated excimer band at ∼380 nm. Fluorescence off–on–off behavior has been clearly demonstrated on the basis of the binding variability of Cu2+ to L. The binding has been elicited through the changes observed in the fluorescence, ESI MS and 1H NMR titrations. All the other metal ions studied do not show any new band and further do not interfere with the recognition of Cu2+ by L, even when these are present in the same medium. The structural features of both the mono- and di-nuclear complexes were established by DFT computational calculations and found to display highly distorted geometry about the copper centers that deviate from both the tetrahedral and the square planar.
一种苯并咪唑附加三唑连接的 1,3-二共轭钙[4]炔(L)已被合成并表征。在所研究的 13 种不同金属离子中,共轭物 L 通过在 ∼380 nm 处新产生的准分子带显示出比率荧光变化,从而识别 Cu2+。通过荧光、ESI MS 和 1H NMR 滴定中观察到的变化,可以诱发这种结合。所研究的所有其他金属离子都没有显示任何新的波段,也不会进一步干扰 L 对 Cu2+ 的识别,即使这些金属离子存在于同一介质中也是如此。通过 DFT 计算确定了单核和双核配合物的结构特征,并发现铜中心的几何形状高度扭曲,偏离了四面体和方形平面。