Departamento de Química Orgánica, Universidad de Murcia, Campus de Espinardo, 30100, Murcia, Spain.
Dalton Trans. 2018 Nov 13;47(44):15941-15947. doi: 10.1039/c8dt03736a.
A 2-haloimidazole-tetraphenylethylene ion-pair receptor 1 is shown to recognise only HSO4- anions in the presence of a cobound Zn2+ cation guest species, which induced a remarkable increase with concomitant blue shift of the emission band of the complex [1·2Zn]4+ whereas no affinity of the free receptor 1 by the anions is observed. In addition, the downfield shifts observed by 1H NMR of the Ha, Hb and Hc protons of the complex [1·2Zn]4+ upon the addition of HSO4- anions indicate their participation in the recognition event. According to DFT studies, upon chelating a Zn2+ cation with two imidazole nitrogen atoms, receptor 1 adopts a conformation ideally fitted to recognise HSO4- through a combination of C(sp2)-HO and C(sp3)-HO hydrogen bondings, C+(sp2)-BrO halogen bonding and C(sp2)O tetrel bonding.
一种 2-卤代咪唑-四苯乙烯离子对受体 1 被证明仅在存在共束缚 Zn2+阳离子客体物种的情况下识别 HSO4-阴离子，这导致配合物 [1·2Zn]4+的发射带发生显著蓝移伴随其增强，而游离受体 1 对阴离子没有亲和力。此外，在添加 HSO4-阴离子时，通过 1H NMR 观察到配合物 [1·2Zn]4+的 Ha、Hb 和 Hc 质子的向场位移表明它们参与了识别事件。根据 DFT 研究，当用两个咪唑氮原子螯合 Zn2+阳离子时，受体 1 采用一种构象，通过 C(sp2)-HO 和 C(sp3)-HO 氢键、C+(sp2)-BrO 卤键和 C(sp2)O 四键的组合，理想地适合于识别 HSO4-。
