Tuned Cd²⁺ Selectivity: Showcase of Electronic and Regio-Effect of π-Extended Di-2-Picolylamine-Substituted Quinoline-Based Tolans.

ABSTRACT: π-Extended di-2-picolylamine (DPA)-substituted 8-hydroxyquinoline (8-HQ) tolans (2) were synthesized for testing electronic and regio-effects. The electron-poor CN-tolan (2b) showed clear selectivity for Cd²⁺ (>>Zn²⁺) over other metal ions via turn-on fluorescence, while the electron-rich MeO-tolan (2a) displayed no clear metal selectivity. Furthermore, considering that there was no significant energy difference between the Cd²⁺ complexes of 1 and 2b, the intended regio-effect (7- vs. 5-substituted effect) did not induce steric hindrance. Thus, the regio-effect is mainly electronic. Considering the above, 2a and 2b constitute a complete showcase in which electronic and regio-effects modulate the metal selecti

SUBMITTER: Ko MS 

PROVIDER: S-EPMC7916104 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature