Supramolecular motifs in s-block metal bound sulfonated monoazo dyes

Abstract

The solid-state structures of sodium and calcium complexes of the simple sulfonated azo dyes ([O₃SC₆H₄NNC₆H₃RR′]⁻ R = H, R′ = OH or NH₂; R = OH, R′ = OH) form a series of supramolecular arrays, with one-, two- and three-dimensional structural motifs and with inorganic coordination networks supporting organic channels. The dominant inorganic networks are formed via coordination to sulfonate groups, water molecules and the amine units, whilst the available hydroxyl groups form only hydrogen-bonds. The nature of the networks is dependent on the metal ion used with sodium ions forming close linked sheets, chains and cages reminiscent of many inorganic minerals whilst the calcium ions adopt ring-ladder structures comparable to those found in s-block amide chemistry.