Cation-Selective and Anion-Controlled Fluorogenic Behaviors of a Benzothiazole-Attached Macrocycle That Correlate with Structural Coordination Modes

• Published in: Inorganic chemistry 2016-08, Vol.55 (15), p.7448-7456
• Main Authors: Ju, Huiyeong, Chang, Duk Jin, Kim, Seulgi, Ryu, Hyunsoo, Lee, Eunji, Park, In-Hyeok, Jung, Jong Hwa, Ikeda, Mari, Habata, Yoichi, Lee, Shim Sung
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.6b00690

We report how the metal cation and its counteranions cooperate in the complexation-based macrocyclic chemosensor to monitor the target metal ion via the specific coordination modes. The benzothiazolyl group bearing NO2S2-macrocycle L was synthesized, and its mercury­(II) selectivity (for perchlorate salt) as a dual-probe channel (UV–vis and fluorescence) chemosensor exhibiting the largest blue shift and the fluorescence turn-off was observed. In the mercury­(II) sensing with different anions, except ClO4 – and NO3 –, no responses for mercury­(II) were observed with other anions such as Cl–, Br–, I–, SCN–, OAc–, and SO4 2–. A crystallographic approach for the mononuclear mercury­(II) perchlorate complex [Hg­(L)­(ClO4)2]·0.67CH2Cl2 (1) and polymeric mercury­(II) iodide complex [Hg­(L)­I2] n (2) revealed that the observed anion-controlled mercury­(II) sensing in the fluorescence mainly stems from the endo- and exocoordination modes, depending on the anion coordinating ability, which induces either the Hg–Ntert bond formation or not. The detailed complexation process with mercury­(II) perchlorate associated with the cation sensing was also monitored with the titration methods by UV–vis, fluorescence spectroscopy, and cold-spray ionization mass spectrometry.