Indyllithium and the Indyl Anion [InL]- : Heavy Analogues of N-Heterocyclic Carbenes

Reduction of the indate complex In(NONAr)(mu-Cl)(2)Li(OEt2)(2) (NONAr = [O(SiMe2NAr)(2)](2); Ar = 2,6-iPr(2)C(6)H(3)) with sodium generates the In-II diindane species [In(NONAr)](2). Further reduction with a mixture of potassium and [2.2.2] crypt affords the In-I N-heterocyclic indyl anion [In(NONAr)](-), which crystallizes with a non-contacted [K([2.2.2] crypt)](+) cation. The indyl anion can also be isolated as the indyllithium compound In(NONAr)(Li{THF}(3)), which contains an In-Li bond. Density functional theory calculations show that the HOMO of the indyl anion isametal-centred lone pair, and preliminary reactivity studies confirm its nucleophilic behaviour.