STANNYLATION EXPERIMENTS WITH NH-FUNCTION AL AMINOIMINOPHOSPHORANES -SYNTHESIS AND STRUCTURE OF THE TRICYCLIC STANNAPHOSPHAZENES [ME2SN((BU2PN)-BU-T)NH](2) AND [(BU2SN)-BU-N(PH2PN)(2)NH](2)

Aminoiminophosphoranes (Bu2P)-Bu-t(NH)NH2 (1) and (H2NPPh2)N(Ph2PNH) ( 2) react with diaminostannanes R2Sn(NEt2)(2) by cyclocondensation to g ive cyclostanna-phosphazenes [Me2Sn((Bu2PN)-Bu-t)NH](2) (3) and [R2Sn( Ph2PN)(2)NH](2) (4 a, b) (a: R = Me, b: R = Bu-n). With 2 and Me3SnNEt 2 the ring compound Me2Sn(Ph2PN)(2)NSnMe3 (5) besides Me4Sn is formed by per-N-stannylation and Sn-methyl group transfer. The crystal struct ures of 3 and 4b were determined by X-ray structure analysis. 3 forms a planar heterotricyclus containing three four-membered rings with two pentacoordinated tin atoms (space group P (1) over bar (No. 2); Z = 1 ). 4b consists of a tricyclic molecule with two puckered six-membered rings and one planar four membered tin-nitrogen ring with two pentacoo rdinated tin atoms (space group P (1) over bar (No. 2); Z = 1).