Design, synthesis and photophysical studies of simple fluorescent anion PET sensors using charge neutral thiourea receptors
Design, synthesis and photophysical studies of simple fluorescent anion PET sensors using charge neutral thiourea receptors
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DOI：
10.1039/b404706k
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发表时间：
2004-01-01
影响因子：
3.2
通讯作者：
Glynn, M
中科院分区：
文献类型：
--
作者：
Gunnlaugsson, T;Davis, AP;Glynn, M
本文报道了四种阴离子荧光光诱导电子转移（PET）化学传感器的合成。这些都是基于一个简单的设计，采用电荷中性的脂肪族或芳香族硫脲阴离子受体连接到蒽荧光团通过亚甲基间隔。此处，阴离子识别通过硫脲质子与阴离子之间的1：1氢键发生，如通过观察DMSO-d（6）中的H-NMR的变化所证明的，其中两个硫脲质子在添加阴离子后向下移动。而1-3被设计用于检测阴离子，如氟离子，乙酸根或磷酸根，4是用于识别N-保护的氨基酸。所有的传感器表现出“理想”的行为，其中只有荧光发射被淬灭后，阴离子识别，由于增强的效率，从受体的荧光团的激发态的电子转移淬灭。通过简单地改变硫脲取代基的性质，可以调节或调谐硫脲受体部分的酸度，改变阴离子识别的灵敏度。对于1，阴离子选择性和荧光猝灭程度的顺序为F- > AcO- > H_2PO_4-，未检测到Cl-和Br-。
The synthesis of four fluorescent photoinduced electron transfer (PET) chemosensors 1-4 for anions is described. These are all based on a simple design employing charge neutral aliphatic or aromatic thiourea anion receptors connected to an anthracene fluorophore via a methylene spacer. Here the anion recognition occurred through 1 : 1 hydrogen bonding between the thiourea protons and the anion, as demonstrated by observing the changes in the H-1 NMR in DMSO-d(6) where the two thiourea protons were shifted down field upon addition of anions. Whereas 1-3 were designed for the detection of anions such as fluoride, acetate or phosphate, 4 was made for the recognition of N-protected amino acids. All the sensors showed 'ideal' behaviour where only the fluorescence emission was quenched upon anion recognition, due to enhanced efficiency of electron transfer quenching from the receptor to the excited state of the fluorophore. By simply varying the nature of the thiourea substituent it was possible to modulate, or tune, the acidity of the thiourea receptor moiety, altering the sensitivity of the anion recognition. For 1, the anion selectivity and the degree of the fluorescence quenching were in the order of F- > AcO- > H2PO4-, with Cl- or Br- not being detected.