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

The syntheses and crystal structures of four hydrothermally prepared organo--zinc phosphites, it viz. poly[[(2-amino-3-methylpyridine)-$$$-phosphonato-zinc] hemihydrate], [Zn(HPO$$)(C$$H$$N$$)]$0.5H$$O$it n$, (I), poly[(2-amino-4-methylpyridine)-$$$-phosphonato-zinc], [Zn(HPO$$)(C$$H$$N$$)]$it n$, (II), poly[(2-amino-5-methylpyridine)-$$$-phosphonato-zinc], [Zn(HPO$$)(C$$H$$N$$)]$it n$, (III), and poly[bis(2-amino-4-methylpyridinium) [tetra-$$$-phosphonato-trizinc] monohydrate], (C$$H$$N$$)$$[Zn$$(HPO$$)$$]$H$$O$it n$, (IV), are described. Compounds (I)--(III) are constructed from vertex-sharing ZnO$$N tetrahedra (the organic molecule acting as a ligand) and HPO$$ pseudo pyramids in a 1:1 ratio to generate the same it motif of infinite 4-ring `ladder' chains propagating in the [010], [101] and [100] directions, respectively, whereas (IV) consists of (010) layers of vertex-sharing ZnO$$ and HPO$$ units in a 3:4 ratio with the protonated organic molecule acting as a template. When an excess of HCl is used in the synthesis, the simple hydrated molecular salt, bis(2-amino-3-methylpyridinium) tetrachlorozincate monohydrate, (C$$H$$N$$)$$[ZnCl$$]$H$$O, (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.