Synthesis of aryl selenides using arylmercurials. Cyclopalladation of Se(R)Ph [R = C6H3(NNC6H4Me-4′)-2,Me-5]. Crystal structures of Se2R2 and [Pd{C6H3[NNC6H3(SePh)-2′,Me-4′]-2,Me-5}Cl]

Abstract

The compound SePhCl reacted with HgR₂ or Hg(R)Cl [R = C₆H₃(NNC₆H₄Me-4′)-2,Me-5] to give Se(R)Ph 1. Reaction between SeCl₄ and Hg(R)Cl or HgR₂ afforded Se(R)Cl, which reacts with HgR₂ affording SeR₂2 and is reduced with hydrazine hydrate to give RCl 3 and Se₂R₂4. Palladium(II) chloride reacted with 1 to give [P[graphic omitted]ePh)-2′,Me-4′]-2,Me-5}Cl]5 and with 2 or 4 to give Se(R)Cl. The crystal structures of compounds 4 and 5 were determined. The geometry of the diselenide 4 offers various possibilities for co-ordination and in the palladium complex 5 two chelate five-membered rings are formed by co-ordination through o-carbon, nitrogen and selenium.