A novel and convenient synthesis towards 2-pyridylselenium compounds:: X-ray crystal structure of 4,4′-dimethyl-2,2′-dipyridyl diselenide and tris(2-pyridylseleno)methane

Various 2,2'-dipyridyl diselenides were prepared by a simple and convenient method employing non-cryogenic conditions. The diselenide anion, Se-2(2-) formed by reducing elemental selenium with 100% hydrazine hydrate in sodium hydroxide reacts in situ with 2-bromopyridines to afford the title compounds in good to excellent yields. Hydrazine hydrate readily cleaves the selenium-selenium bond in these diselenides to generate 2-pyridylselenolate anion, which reacts with halomethanes to afford 2-pyridylseleno methanes. X-ray crystal structure of 4,4'-dimethyl-2,2'-dipyridyl diselenide (4) and tris(2-pyridylseleno)methane (10) is described. (C) 2002 Elsevier Science B.V. All rights reserved.