Benzotriazolate cage complexes of tin(II) and lithium: halide-influenced serendipitous assembly

The one-pot reactions of the tin(II) halides SnX(2) (X = F, Cl, Br, I) with lithium hexamethyldisilazide, Li(hmds)], and benzotriazole, (bta)H, produce contrasting outcomes. Tin(II) fluoride does not react with Li(hmds)] and (bta)H, the outcome being the formation of insoluble Li(bta)](∞). Tin(II) chloride and tin(II) bromide react with Li(hmds)] and (bta)H in toluene to produce the hexadecametallic tin(II)-lithium cages (hmds)(8)Sn(8)(bta)(12)Li(8)X(4)]·(n toluene) X = Cl, 3·(8 toluene); X = Br, 4·(3 toluene)]. The reaction of tin(II) iodide with Li(hmds)] and (bta)H in thf solvent produces the ion-separated species {(thf)(2)Li(bta)}(3){Li(thf)}](2)SnI(4)]·(thf), 5](2)SnI(4)]·(thf), the structure of which contains a cyclic trimeric unit of lithium benzotriazolate and a rare example of the tetraiodostannate(II) dianion.