Formation of lithium, sodium and potassium complexes with 1,3,5-triamino-1,3,5-trideoxy-cis-inositol (taci).

Abstract

Single crystals of (1,3-diamino-5-azaniumyl-1,3,5-trideoxy-cis-inositol-κ(3)O(2),O(4),O(6))(1,3,5-triamino-1,3,5-trideoxy-cis-inositol-κ(3)O(2),O(4),O(6))lithium(I) diiodide dihydrate, [Li(C6H16N3O3)(C6H15N3O3)]I2·2H2O or [Li(Htaci)(taci)]I2·2H2O (taci is 1,3,5-triamino-1,3,5-trideoxy-cis-inositol), (I), bis(1,3,5-triamino-1,3,5-trideoxy-cis-inositol-κ(3)O(2),O(4),O(6))sodium(I) iodide, [Na(C6H15N3O3)2]I or [Na(taci)2]I, (II), and bis(1,3,5-triamino-1,3,5-trideoxy-cis-inositol-κ(3)O(2),O(4),O(6))potassium(I) iodide, [K(C6H15N3O3)2]I or [K(taci)2]I, (III), were grown by diffusion of MeOH into aqueous solutions of the complexes. The structures of the Na and K complexes are isotypic. In all three complexes, the taci ligands adopt a chair conformation with axial hydroxy groups, and the metal cations exhibit exclusive O-atom coordination. The six O atoms of the resulting MO6 unit define a centrosymmetric trigonal antiprism with approximate D3d symmetry. The interligand O···O distances increase significantly in the order Li < Na < K. The structure of (I) exhibits a complex three-dimensional network of R-NH2-H···NH2-R, R-O-H···NH2-R and R-O-H···O(H)-H···NH2-R hydrogen bonds. The structures of the Na and K complexes consist of a stack of layers, in which each taci ligand is bonded to three neighbours via pairwise O-H···NH2 interactions between vicinal HO-CH-CH-NH2 groups.