描述了两种新型化学传感器1和2的设计,合成和光物理评估,用于选择性检测pH 7.4的水中的Cd(II)。两者均基于使用芳族亚氨基二乙酸酯受体,该受体通过共价甲基间隔基与蒽荧光团连接。这些是高度水溶性的传感器,由于受体对蒽激发态的光诱导电子转移(PET)猝灭,因此在pH值为3-11时荧光会“关闭”。然而,受体质子化后,发射被“接通”。根据这些变化,确定1和2的pK a s为1.8和2.5分别。两者都显示出对Cd(II)优于竞争性离子(如II组和Zn(II),Cu(II),Co(II))的良好选择性。对于具有单个受体的1,对于游离传感器,在pH 7.4(HEPES缓冲液,135 mM NaCl)下仅观察到弱的蒽蒽排放。Zn(II)滴定后,出现了宽红移发射,中心在468 nm。在Cd(II)存在下,也观察到了类似的红移发射,但是这次集中在506 nm处。与这些结果相反,由于抑制了PET,在Zn(
描述了两种新型化学传感器1和2的设计,合成和光物理评估,用于选择性检测pH 7.4的水中的Cd(II)。两者均基于使用芳族亚氨基二乙酸酯受体,该受体通过共价甲基间隔基与蒽荧光团连接。这些是高度水溶性的传感器,由于受体对蒽激发态的光诱导电子转移(PET)猝灭,因此在pH值为3-11时荧光会“关闭”。然而,受体质子化后,发射被“接通”。根据这些变化,确定1和2的pK a s为1.8和2.5分别。两者都显示出对Cd(II)优于竞争性离子(如II组和Zn(II),Cu(II),Co(II))的良好选择性。对于具有单个受体的1,对于游离传感器,在pH 7.4(HEPES缓冲液,135 mM NaCl)下仅观察到弱的蒽蒽排放。Zn(II)滴定后,出现了宽红移发射,中心在468 nm。在Cd(II)存在下,也观察到了类似的红移发射,但是这次集中在506 nm处。与这些结果相反,由于抑制了PET,在Zn(
[GRAPHIC]Compounds 1 and 2 were designed as fluorescent chemosensors for Cd(II). For both, a selective determination of Cd(II) over Zn(II) was achieved. The fluorescence emission of both was pH-independent and switched off between pH 3-11 in 100% water. Whereas the recognition of Cd(II) at pH 7.4 gave rise to the formation of charge-transfer complexes (exciplexes) for both (lambda(max) ca. 500 and 506 nm, respectively), the recognition of Zn(II) only switched on the (monomeric) anthracene emission of 2, while for 1 it was red-shifted (lambda(max) = 468 nm).
Highly selective fluorescent chemosensors for cadmium in water
to typical monomeric anthracene emission, due to suppression of PET, that is, the anthracene emission was ‘switched on’. Nevertheless, in the presence of Cd(II) a broad emission centred at 500 nm was observed, similar to that seen for 1. These ion induced long wavelength emission bands were assigned to the formation of charge-transfer complexes (exciplexes) between the anthracene moieties and the ion-receptor
描述了两种新型化学传感器1和2的设计,合成和光物理评估,用于选择性检测pH 7.4的水中的Cd(II)。两者均基于使用芳族亚氨基二乙酸酯受体,该受体通过共价甲基间隔基与蒽荧光团连接。这些是高度水溶性的传感器,由于受体对蒽激发态的光诱导电子转移(PET)猝灭,因此在pH值为3-11时荧光会“关闭”。然而,受体质子化后,发射被“接通”。根据这些变化,确定1和2的pK a s为1.8和2.5分别。两者都显示出对Cd(II)优于竞争性离子(如II组和Zn(II),Cu(II),Co(II))的良好选择性。对于具有单个受体的1,对于游离传感器,在pH 7.4(HEPES缓冲液,135 mM NaCl)下仅观察到弱的蒽蒽排放。Zn(II)滴定后,出现了宽红移发射,中心在468 nm。在Cd(II)存在下,也观察到了类似的红移发射,但是这次集中在506 nm处。与这些结果相反,由于抑制了PET,在Zn(