Synthesis, properties, and multinuclear (1H, 13C, 77Se) nuclear magnetic resonance studies of selenoethers containing two or more selenium atoms

Abstract

A convenient synthesis of MeSeLi from MeLi and Se₈ in tetrahydrofuran (THF) has been used to prepare the bis-selenoethers MeSe[CH₂]_nSeMe (n= 1,2,3,6, or 12) and cis-MeSeCHCHSeMe. PhSe[CH₂]_nSePh (n= 1–3) and cis-PhSeCHCHSePh have been prepared from PhSe^–, itself produced from Ph₂Se₂ and LiAIH₄–THF or sodium hydroxymethanesulphinate. The bis-selenoethers o-C₆H₄(SeR)₂(R = Me or Ph) were obtained from R₂Se₂ and benzyne. The syntheses of (RSeCH₂)₃CMe (R = Me or Ph), (MeSeCH₂)₄C, and (MeSeCH₂CH₂CH₂)₂Se are also described. The ¹H, ¹³C, and ⁷⁷Se n.m.r. spectra of these selenoethers have been recorded, and the chemical shifts and coupling constants (ⁿJ_Se–H, ⁿJ_Se–C) are discussed in terms of structures. Mass spectra of the selenoethers have been recorded and the principle fragmentation modes identified.