Anthracene-tethered aminomethyl oxadiazole chemosensor: a probe offering selective chromo- and fluorogenic signalings for targeting Cu(II)
作者:Sabir H. Mashraqui、Tabrez Khan、Mukesh Chandiramani、Rupesh Betkar、Kiran Poonia
DOI:10.1007/s10847-009-9717-4
日期:2010.8
A new optical chemosensor featuring anthracene as a fluorophore and an aminomethyl oxadiazole moiety as a bidentate chelate has been synthesized. From photophysical studies, we find the probe to offer remarkably selective chromo- and fluorogenic signaling responses towards biologically and environmentally significant Cu2+. In the presence of Cu2+, fluorescence is quenched to the extent of 95%, while the absorbance due to the anthracene chromophore is nearly completely bleached out. On the other hand, Li+, Na+, K+, Ba2+, Ca2+, Zn2+, Mg2+, Cd2+, Co2+, Ni2+, Ag+, Pb2+ and Hg2+ even at 10 times higher concentration than Cu2+ do not cause detectable photophysical perturbations. The stability constants, logK for Cu2+ were calculated to be 4.36 and 4.76 on the basis of spectrophotometric and fluorimetric titrations, respectively. However, logKs for other metal ions are too low (<0.1) to pose any interferences in the optical detection of Cu2+. Though, not fully defined, the uncommon phenomenon of the absorbance bleaching by Cu2+ is tentatively explained by invoking the involvement of non-covalent anthracene-Cu2+ complex.
我们合成了一种新的光学
化学传感器,它以
蒽为荧光团,以
氨基甲基噁二唑分子为双叉螯合物。通过光物理研究,我们发现该探针对具有
生物和环境意义的 Cu2+ 具有显著的选择性发色和荧光信号反应。在 Cu2+ 存在的情况下,荧光被淬灭 95%,而
蒽发色团的吸光度几乎完全被漂白。另一方面,Li+、Na+、K+、Ba2+、Ca2+、Zn2+、Mg2+、Cd2+、Co2+、Ni2+、Ag+、Pb2+ 和 Hg2+ 即使浓度比 Cu2+ 高 10 倍,也不会引起可检测到的光物理扰动。根据分光光度法和荧光滴定法计算,Cu2+ 的稳定常数 logK 分别为 4.36 和 4.76。然而,其他
金属离子的 logK 太低(0.1),不会对 Cu2+ 的光学检测造成任何干扰。Cu2+ 对吸光的漂白这一不常见的现象虽然还没有完全确定,但可以初步解释为非共价
蒽-Cu2+ 复合物的参与。