Utilizing Selective Chlorination to Synthesize New Triangulenium Dyes was written by Jensen, Jesper Dahl;Bisballe, Niels;Kacenauskaite, Laura;Thomsen, Maria Storm;Chen, Junsheng;Hammerich, Ole;Laursen, Bo W.. And the article was included in Journal of Organic Chemistry in 2021.Quality Control of Pyridinehydrochloride This article mentions the following:
Functionalization of new sites on the triangulenium structure has been achieved by early stage chlorination with N-chlorosuccinimide (NCS), giving rise to two new triangulenium dyes (1 and 3). By introducing the chlorine functionalities in the acridinium precursor, positions complementary to those previously accessed by electrophilic aromatic substitution on the final dyes are accessed. The chlorination is selective, giving only one regioisomer for both mono- and dichlorination products. For the monochlorinated acridinium compound a highly selective ring-closing reaction was discovered, generating a single regioisomer of the cationic [4]helicene product. Further investigations into the mechanism of [4]helicene formation lead to the first isolation of the previously proposed intermediate of the two-step SNAr reaction, key to all aza-bridged triangulenium and helicenium systems. Late-stage functionalization of DAOTA+ with NCS gave rise to a different dichlorinated compound (2). The fully ring closed chlorinated triangulenium dyes 1, 2 and 3 show red shift in absorption and emission, while maintaining relatively high fluorescence quantum yields of 36%, 26%, and 41%, and long fluorescence lifetimes of 15 ns, 12.5 and 16 ns, resp. Cyclic voltammetry shows that chlorination of the triangulenium dyes significantly lowers reduction potentials and thus allows for efficient tuning of redox and photoredox properties. In the experiment, the researchers used many compounds, for example, Pyridinehydrochloride (cas: 628-13-7Quality Control of Pyridinehydrochloride).
Pyridinehydrochloride (cas: 628-13-7) belongs to pyridine derivatives. Pyridines are an important class of heterocycles and occur in polysubstituted forms in many naturally occurring biologically active compounds, drug molecules and chiral ligands. Halopyridines are particularly attractive synthetic building blocks in a variety of cross-coupling methods, including the Suzuki-Miyaura cross-coupling reaction.Quality Control of Pyridinehydrochloride