Isolation and Structural Characterization of New Indium(III) Aqua Complexes:trans-[InCl2(H2O)4]+ andtrans-[InCl4(H2O)2]− as Supramolecular Adducts with Cucurbituril and Related Studies

Abstract

Aqua and aqua-chloride complexes of AlIII and InIII have been isolated from aqueous solutions and structurally characterized by X-ray analysis as supramolecular adducts with cucurbituril. Using this approach, trans-[InCl2(H2O)4]+ and trans-[InCl4(H2O)2]− species were detected and isolated for the first time as parts of supramolecular assemblies of [InCl2(H2O)4]3Cl3·(C36H36N24O12)·4H2O (1) and (H3O)3[InCl4(H2O)2]3·2(C36H36N24O12)·17H2O (2). The hexaaqua indium(III) cation is present in [In(H2O)6](NO3)3·(C36H36N24O12)·9H2O (3), and its geometry has been established by X-ray crystallography for the first time. The preparation and crystal structure of an AlIII hexaaqua ion − cucurbituril adduct [Al(H2O)6]Cl3·(C36H36N24O12)·18H2O (4) is also reported. A comparison of InIII with its analogs in Group 13 shows closer similarity between InIII and TlIII in the chloroaqua complexes than between In and its lighter congeners.