Hydrogen bonding adducts of octamolybdate anions containing coordinately bound pyridiniumoxides

Abstract

The reaction of [Mo 7O 24][NH 4] 6 with 3-hydroxypyridine (3-HOPy) and 4-hydroxypyridine (4-HOPy) in water resulted in the crystalline materials of [Mo 8O 26(3-OPyH) 2][3-HOPyH] 4 · 4H 2O ( 1) and [Mo 8O 26(4-OPyH) 2][4-HOPyH] 4 · 4H 2O ( 2), respectively. Crystal structures of the complexes 1 and 2 reveal that two of the OPyH moieties coordinately linked to two molybdate atoms of Mo 8O 26 clusters. The crystal structures of 1 and 2 are not iso-structural. However, in both cases the iso-structural Mo 8O 26(OPyH) 2 units join together via N–H⋯O hydrogen bonds to form linear ribbons which are further joined by H 2O molecules to form 2D-layers. The cavities or channels of these layers are occupied by the C–H⋯O, O–H⋯O and O–H⋯π aggregates of hydroxypyridinium cations.