In chemistry, triphenylcarbenium,[1]triphenylmethyl cation, tritylium ,[2] or trityl cation is an ion with formula [C19H15]+ or (C6H5)3C+, consisting of a carbon atom with a positive charge connected to three phenyl groups. It is a charged version of the triphenylmethyl radical(C6H5)3C•. The name is often abbreviated to triphenylmethyl or trityl in salts, although these names also denote the chemical group in compounds like triphenylmethyl chloride that do not contain the cation.[3]
Triphenylcarbenium is a relatively stable carbenium ion, because the positive charge is partially distributed among 10 of the carbon atoms (the 3 carbon atoms in the ortho and para positions of each of the three phenyl groups, plus the central carbon atom).[4][5]
Triarylmethane dyes are derivatives that are stabilized versions of the trityl cation. They are water-soluble and are often obtained as the chloride salts. These dyes have strong electron donor groups, often amines, at the p-positions of two or three of the aryl groups.[7]
^ abMichael E. Jung, Roman Lagoutte, and Ullrich Jahn (2011): "Triphenylcarbenium Tetrafluoroborate". In Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rt362.pub2
^Naidu, Veluru Ramesh; Ni, Shengjun; Franzén, Johan (2015). "The Carbocation: A Forgotten Lewis Acid Catalyst". ChemCatChem. 7 (13): 1896–1905. doi:10.1002/cctc.201500225. S2CID98267361.
^ abN. C. Deno, J. J. Jaruzelski, and Alan Schriesheim (1955) "Carbonium ions. I. An acidity function (C0) derived from arylcarbonium ion equilibria." Journal of the American Chemical Society, voume 77, issue 11, pages 3044–3051. doi:10.1021/ja01616a036
^E. Molins, M. Mas, W. Maniukiewicz, M. Ballester and J. Castañer (1996): "Perchlorotriphenylcarbenium Hexachloroantimonate(V)". Acta Crystallographica Section C (Structural Chemistry), volume C52, pages 2412-2414. doi:10.1107/S0108270196007287