Recently there has been considerable interest in alkali metal derivatives of polyimido anions of p-block elements, for example [Sb(NR) [^-^^ The replacement of one (or more) of the bulky NR groups in the anions of these clusters by the isoelectronic 0x0 ligand may have significant structural consequences, but the diazasulfite anions [0S(NR)(NR)l2 (2) are unknown. We describe here the syntheses of dilithium derivatives of the bis(tert-buty1imido)sulfite dianion, [OS(N~BU),]* -(2a), and the (tert-butylimido)(trimethylsilylimido)sulfite dianion, [OS(NtBu)(NSiMe,)]* -(2b), which adopt unique cluster structures derived from the aggregation of hexagonal prisms and eighteen atom cages, respectively.:
R N & + NRThe reactions of the chalcogen diimides, tBuN=E=NtBu, with two equivalents of LiNHtBu produce the dianions [E(NtBu>,l2-(E = S, Se, Te) in excellent y i e l d~. [~-~] By analogy, the treatment of tert-butylsulfinylimine, tBuNSO, or trimethylsilylsulfinylimine, Me,SiNSO, with two equivalents of lithium tert-butylamide leads to hexameric dilithium bis( tertbuty1imido)sulfite 3 and hexameric dilithium (tert-buty1imido)-(trimethylsily1imido)sulfite 4, respectively [Eq. (a), cf. reac-tions of RNSO with other bases, e.g. Li[N(SiMe,)R], which lead to mixed sulfurdiimides, RNSNR]A crystal structure determination of 3 revealed a remarkable arrangement of thirty-six atoms of main group elements in a Li12N,,0,S, cluster with a central Li,O, core, which comprises two parallel, six-membered Li,O, rings in their chair conformations (Figure l ) . [ ' *The cage structure consists of six pyramidal [0S(NtBu),l2-ions (mean bond angles: NSN 104.2(5)",[*] Prof.