In this work we report on the synthesis of a pyridyl/phenolic/benzothiazole functionalized colorimetric receptor (BPAP) that can selectively recognise Fe(III) and Fe(II) ions in aqueous medium with visible, naked eye colour changes. Moreover, BPAP behaves as a ‘turn-on’ fluorescent chemosensor, showing an excellent sensitivity towards Zn²⁺ and Cd²⁺ cations in water by exhibiting fluorometric change. BPAP exhibited a visible detection limit of 5.5 μM and 2.5 μM for Fe³⁺ and Fe²⁺, respectively, and a fluorometric selectivity towards Zn²⁺ and Cd²⁺ ions with lower detection limits of 205 nM and 642 nM. To understand the mode of binding to the sensor, both the nude sensor and the Zn-complex were isolated and characterized by X-ray crystallography. In Zn-BPAP, the ligand acts as neutral tridentate through N_pyridine, N_amine and N_amide donor atoms. The N atom of benzothiazole group and the OH group of the phenole unit are not coordinated. Computational DFT study was performed on the free ligand BPAP and complex with Zn²⁺ to investigate the interaction site, to calculate the energies of the frontier molecular orbitals and to corroborate some of the experimental results.

在这项工作中，我们报告了吡啶/酚/苯并噻唑官能比色受体（BPAP）的合成，该受体可以选择性地识别水性介质中具有可见肉眼颜色变化的Fe（III）和Fe（II）离子。此外，BPAP表现为“开启式”荧光化学传感器，通过显示荧光变化，对水中的Zn ²⁺和Cd ²⁺阳离子显示出极好的敏感性。BPAP对Fe ³⁺和Fe ²⁺的可见检测极限分别为5.5μM和2.5μM ，并且对Zn ²⁺和Cd ²⁺的荧光选择性检出限较低的离子分别为205 nM和642 nM。为了了解与传感器的结合方式，裸传感器和Zn-络合物都被分离并通过X射线晶体学表征。在Zn-BPAP中，配体通过N_吡啶，N_胺和N_酰胺供体原子充当中性三齿。苯并噻唑基的N原子与酚单元的OH基不配位。对游离配体BPAP及其与Zn ^2+的络合物进行了计算DFT研究，以研究相互作用部位，计算前沿分子轨道的能量并证实一些实验结果。