What is "thionine"

Thionine \Thi"on*ine\, n. [Gr. ? brimstone, sulphur.] (Chem.) An artificial red or violet dyestuff consisting of a complex sulphur derivative of certain aromatic diamines, and obtained as a dark crystalline powder; -- called also phenylene violet.

n. (context chemistry English) An artificial red or violet dyestuff consisting of a complex sulfur derivative of certain aromatic diamines.

Thionine, also known as thionine acetate or Lauth's violet, is a strongly staining metachromatic dye, featuring a phenothiazine core, that is widely used for biological staining. Thionine can also be used in place of Schiff reagent in quantitative Feulgen staining of DNA. It can also be used to mediate electron transfer in microbial fuel cells. The dye's name is frequently misspelled, with omission of the e. The -ine ending indicates that the compound is an amine.

When both the amines are dimethylated, the product tetramethyl thionine is famous as methylene blue, and the intermediates are Azure C (Monomethyl thionine), Azure A (when one of the amines is dimethylated and the other remains primary amine), and Azure B (Trimethyl thionine). When methylene blue is "polychromed" by ripening (Oxidized in solution or metabolized by fungal contamination, as originally noted in the thesis of Dr D L Romanowski in 1890s), it forms thionine and all the Azure intermediates.

• Thionin : protein
• Thionine : dye
• (2Z,4Z,6Z,8Z)-Thionine : simple heterocycle