The author of 《Excimer Disaggregation Enhanced Emission: A Fluorescence “”Turn-On”” Approach to Oxoanion Recognition》 were Yang, Jian; Dong, Chao-Chen; Chen, Xu-Lang; Sun, Xin; Wei, Jin-Yan; Xiang, Jun-Feng; Sessler, Jonathan L.; Gong, Han-Yuan. And the article was published in Journal of the American Chemical Society in 2019. Safety of 2,6-Dibromopyridine The author mentioned the following in the article:
A new approach to anion sensing that involves excimer disaggregation induced emission (EDIE) is reported. It involves the anion-mediated disaggregation of the excimer formed from a cationic macrocycle. This leads to an increase in the observed fluorescence intensity. The macrocycle in question, cyclo[1]N2,N6-dimethyl-N2,N6-bis(6-(1H-imidazolium-1-yl)pyridin-2-yl)pyridine-2,6-diamine[1]1,4-dimethylbenzene (12+; prepared as its PF6- salt), is obtained in ca. 70% yield via a simple cyclization. X-ray diffraction analyses of single crystals revealed that, as prepared, this macrocycle exists in a supramol. polymeric form in the solid state. Macrocycle 12+ is weakly fluorescent in acetonitrile. The emission intensity is concentration dependent, with the maximum intensity being observed at [12+] ≈ 0.020 mM. This finding is ascribed to formation of an excimer, followed possibly by higher order aggregates as the concentration of 12+ is increased. Addition of tetrabutylammonium pyrophosphate (HP2O73-) to 12+ (0.020 mM in acetonitrile) produces a ca. 200-fold enhancement in the emission intensity (λex = 334 nm; λem = 390-650 nm). These findings are rationalized in terms of the HP2O73- serving to break up essentially non-fluorescent excited-state dimers of 12+ through formation of a highly fluorescent anion-bound monomeric complex, 12+·HP2O73-. A turn-on in the fluorescence intensity is also seen for H2PO4- and, to a lesser extent, HCO3-. Little (HSO4-, NO3-) or essentially no (N3-, SCN-, F-, Cl-, Br- and I-) response is seen for other anions. Solid-state structural anal. of single crystals obtained after treating 12+ with HP2O73- in the presence of water revealed a salt form wherein a H2P2O72- anion sits above the cone-like macrocycle. In the experimental materials used by the author, we found 2,6-Dibromopyridine(cas: 626-05-1Safety of 2,6-Dibromopyridine)
2,6-Dibromopyridine(cas: 626-05-1) belongs to pyridine. Pyridine is very deactivated towards electrophilic substitution with respect to benzene. For this reason classical formylation, using methods such as the Gattermann or Vilsmeier reactions, are not generally successful. Safety of 2,6-Dibromopyridine