Consistent zincophosphite 4-ring `ladder' chain structural motif with isomeric ligands

The syntheses and crystal structures of four hydrothermally prepared organo–zinc phosphites, viz. poly[[(2-amino-3-methylpyridine)-μ3-phosphonato-zinc] hemihydrate], {[Zn(HPO3)(C6H8N2)]·0.5H2O}n, (I), poly[(2-amino-4-methylpyridine)-μ3-phosphonato-zinc], [Zn(HPO3)(C6H8N2)]n, (II), poly[(2-amino-5-methylpyridine)-μ3-phosphonato-zinc], [Zn(HPO3)(C6H8N2)]n, (III), and poly[bis(2-amino-4-methylpyridinium) [tetra-μ3-phosphonato-trizinc] monohydrate], {(C6H9N2)2[Zn3(HPO3)4]·H2O}n, (IV), are described. Compounds (I)–(III) are constructed from vertex-sharing ZnO3N tetrahedra (the organic molecule acting as a ligand) and HPO3 pseudo pyramids in a 1:1 ratio to generate the same motif of infinite 4-ring `ladder' chains propagating in the [010], [101] and [100] directions, respectively, whereas (IV) consists of (010) layers of vertex-sharing ZnO4 and HPO3 units in a 3:4 ratio with the protonated organic molecule acting as a template. When an excess of HCl is used in the synthesis, the simple hydrated molecular salt, bis(2-amino-3-methylpyridinium) tetrachlorozincate monohydrate, (C6H8N2)2[ZnCl4]·H2O, (V), arises. Compounds (I)–(V) feature extensive networks of hydrogen bonds, both classical (N—H...O, N—H...Cl, O—H...O) and non-classical (C—H...O, C—H...Cl) in nature, which help to consolidate the extended structures.