A new visible light excitable Hg2+ sensor, NBD-TAEE, was prepared by bridging a 4-amino-7-nitro-benzoxadiazole (ANBD) fluorophore with thiaazacrown ethervia an ethylene spacer. Besides the specific Hg2+-induced absorption shift from 466 to 513 nm, this sensor exhibits the specific Hg2+-induced emission enhancement (∼29-fold) and fluorescent pH-independence from pH 6 to 13. Hg2+ addition even leads to the emission red shift from 532 to 570 nm, although NBD-TAEE is not a ratiometric fluorescent sensor due to its emission band being overlaid by the Hg2+-induced band. The instant and reversible “turn-on” Hg2+ response, fine cell permeability and cell imaging ability display its potential application in both environmental and Hg2+-polluted biological samples. Its analogue without the ethylene spacer, NBD-TAE, possesses the higher quantum yield and very poor Hg2+ binding ability. Their different emission behavior and sensing ability suggest that the spacer is quite essential for sensor construction.
通过将 4-amino-7-nitro-benzoxadiazole (ANBD) 荧光团与
噻唑冠
乙醚和
乙烯间隔物桥接,制备了一种新型可见光可激发 Hg2+ 传感器 NBD-TAEE。除了由 Hg2+ 引起的从 466 纳米到 513 纳米的特定吸收位移外,这种传感器还表现出由 Hg2+ 引起的特定发射增强(29 倍)以及从 pH 值 6 到 13 的荧光 pH 值无关性。由于 NBD-TAEE 的发射带被 Hg2+ 诱导的发射带所覆盖,因此它不是一种比率测量型荧光传感器,但 Hg2+ 的加入甚至会导致其发射带从 532 纳米红移到 570 纳米。NBD-TAEE 对 Hg2+ 的瞬时可逆 "开启 "反应、良好的细胞渗透性和细胞成像能力显示了其在环境和 Hg2+ 污染
生物样本中的应用潜力。没有
乙烯间隔的类似物 NBD-TAE 具有更高的量子产率,但与 Hg2+ 的结合能力很差。它们不同的发射行为和传感能力表明,间隔物对传感器的构建至关重要。