Abstract

Two mononuclear compounds, [Fe(H₂O)₅(dpdo)]SO₄·4H₂O 1 and [Cd(dpdo)(H₂O)₃I₂]·0.5dpdo 2 (dpdo⊕=⊕4,4′-bipyridine dioxide) have been obtained from the reactions of (NH₄)₂SO₄·FeSO₄ or CdI₂ with dpdo. The mononuclear units in compound 1 are juxtaposed in head-to-tail mode along the [010] direction and connected through π–π stacking and hydrogen bonding to give a ladder-like motif. These ladders are further linked into a 3D network through hydrogen bonding between SO₄²⁻ anions and water molecules. Compound 2 forms a dimer unit [Cd(dpdo)(H₂O)₃I₂]₂ through π–π stacking and hydrogen bonding. These dimer subunits and solvated dpdo molecules are alternately arrayed in the [011] plane through π–π stacking and hydrogen bonding, leading to a two-dimensional sheet. Intermolecular O⋯I interactions link these sheets, also giving a 3D network.