Direct synthesis of heterocyclic [(RP)nE]– anions using [E(NMe2)3] (E = Sb, As); implications to the mechanism of formation of Zintl compounds

Abstract

The low-temperature reactions of [Sb(NMe₂)₃] with [CyPH₂] and [CyPHNa] (1:1:1 equiv.) and of [As(NMe₂)₃] with [^tBuPHLi] (1:3 equiv.) in TMEDA–thf [TMEDA = Me₂NCH₂)₂] produce [{cyclo-(CyP)₄Sb}Na·Me₂NH·TMEDA]₂ 1 and [{cyclo-(^tBuP)₃As}Li·TMEDA·thf] 2, respectively; at higher temperatures these reactions generate Zintl compounds containing Sb₇^3– and As₇^3– anions.