两个新的希夫碱基,TIC((E)-N'-(2-羟基亚苄基)-5-(噻吩-2-基)异恶唑-3-碳酰肼)和TIE((E)-N'-(3-乙氧基-2-羟基亚苄基)-5-(噻吩-2-基)异恶唑-3-碳酰肼),已被设计和合成为化学传感器，用于识别Ga3和Fe3离子。当与DMSO/H2O缓冲溶液中的Ga3离子配位时，TIE表现出明显的“打开”响应，其特征是清晰的荧光。相比之下,TIC还显示出蓝色荧光的“打开”响应，由于TIE的乙氧基的空间位阻，该响应比TIE更具选择性和敏感性。新形成的复合物TIC-Ga3和TIE-Ga3可以充当针对Fe3离子的选择性“关闭”荧光探针。对Ga3离子的TIC和TIE的检测极限为7.8809×10-9M和2.6277×10-8M，分别。TIC-Ga3和TIE-Ga3对Fe3离子的检测极限为8.6562×10-9M和3.3764×10-7M，分别。传感器与Ga3+或Fe3+离子之间的配合物的摩尔比均为1:2,质谱,和理论计算。两种传感器均用于测定环境水样中的目标离子，并研制成功了检测Ga3+离子的便携式纸质传感器。
Two new Schiff bases, TIC ((E)-N\'-(2-hydroxybenzylidene)-5-(thiophene-2-yl)isoxazole-3-carbohydrazide) and TIE ((E)-N\'-(3-ethoxy-2-hydroxybenzylidene)-5-(thiophene-2-yl)isoxazole-3-carbohydrazide), have been designed and synthesized as chemosensors for distinct recognition of Ga3+ and Fe3+ ions. TIE demonstrated a prominent \"turn on\" response characterized by clear distinguished fluorescence when coordination with Ga3+ ions in the DMSO/H2O buffer solution. In comparison, TIC also showed \"turn on\" response of blue fluorescence which was more selective and sensitive than that of TIE due to the steric hindrance of ethoxy group of TIE. The newly formed complexes TIC-Ga3+ and TIE-Ga3+ may act as selective \"turn-off\" fluorescent probes towards Fe3+ ions. Limits of detection of TIC and TIE towards Ga3+ ions were 7.8809 × 10-9 M and 2.6277 × 10-8 M, respectively. Limits of detection of TIC-Ga3+ and TIE-Ga3+ towards Fe3+ ions were 8.6562 × 10-9 M and 3.3764 × 10-7 M, respectively. The molar ratio of the complex between the sensor and Ga3+ or Fe3+ ions were all 1:2 determined through Job\'s Plot, mass spectrometry, and theoretical calculations. Both sensors were utilized for the determination of target ions in environment water samples, and the portable paper sensors for detecting Ga3+ ions have been successfully developed.
