In 2022,Kole, Goutam Kumar; Koscak, Marta; Amar, Anissa; Majhen, Dragomira; Bozinovic, Ksenija; Brkljaca, Zlatko; Ferger, Matthias; Michail, Evripidis; Lorenzen, Sabine; Friedrich, Alexandra; Krummenacher, Ivo; Moos, Michael; Braunschweig, Holger; Boucekkine, Abdou; Lambert, Christoph; Halet, Jean-Francois; Piantanida, Ivo; Mueller-Buschbaum, Klaus; Marder, Todd B. published an article in Chemistry – A European Journal. The title of the article was 《Methyl Viologens of Bis-(4′-Pyridylethynyl)Arenes – Structures, Photophysical and Electrochemical Studies, and their Potential Application in Biology》.Quality Control of 4-Ethynylpyridine The author mentioned the following in the article:
A series of bis-(4′-pyridylethynyl)arenes (arene = benzene, tetrafluorobenzene, and anthracene) were synthesized and their bis-N-methylpyridinium compounds were investigated as a class of π-extended Me viologens. Their structures were determined by single crystal X-ray diffraction, and their photophys. and electrochem. properties (cyclic voltammetry), as well as their interactions with DNA/RNA were investigated. The dications showed bathochromic shifts in emission compared to the neutral compounds The neutral compounds showed very small Stokes shifts, which are a little larger for the dications. All of the compounds showed very short fluorescence lifetimes (<4 ns). The neutral compound with an anthracene core has a quantum yield of almost unity. With stronger acceptors, the analogous bis-N-methylpyridinium compound showed a larger two-photon absorption cross-section than its neutral precursor. All of the dicationic compounds interact with DNA/RNA; while the compounds with benzene and tetrafluorobenzene cores bind in the grooves, the one with an anthracene core intercalates as a consequence of its large, condensed aromatic linker moiety, and it aggregates within the polynucleotide when in excess over DNA/RNA. Moreover, all cationic compounds showed highly specific CD spectra upon binding to ds-DNA/RNA, attributed to the rare case of forcing the planar, achiral mol. into a chiral rotamer, and negligible toxicity toward human cell lines at ≤10μM concentrations The anthracene-analog exhibited intracellular accumulation within lysosomes, preventing its interaction with cellular DNA/RNA. However, cytotoxicity was evident at 1μM concentration upon exposure to light, due to singlet oxygen generation within cells. These multi-faceted features, in combination with its two-photon absorption properties, suggest it to be a promising lead compound for development of novel light-activated theranostic agents. The experimental part of the paper was very detailed, including the reaction process of 4-Ethynylpyridine(cas: 2510-22-7Quality Control of 4-Ethynylpyridine)
4-Ethynylpyridine(cas: 2510-22-7) belongs to pyridine. Pyridine’s structure is isoelectronic with that of benzene, but its properties are quite different. Pyridine is completely miscible with water, whereas benzene is only slightly soluble. Like all hydrocarbons, benzene is neutral (in the acid–base sense), but because of its nitrogen atom, pyridine is a weak base.Quality Control of 4-Ethynylpyridine