Structures of five salt forms of disulfonated monoazo dyes

Area of Science:

• Coordination Chemistry
• Materials Science
• Crystallography

Background:

• Monoazo dyes are widely used in various industries.
• Understanding the coordination chemistry of metal-dye complexes is crucial for developing new materials.
• Disulfonated dyes offer unique properties compared to their monosulfonated counterparts.

Purpose of the Study:

• To elucidate the crystal structures of five s-block metal salt forms of three disulfonated monoazo dyes.
• To investigate the coordination behavior of azo and water ligands in these complexes.
• To compare the structural dimensionality and packing motifs with related monosulfonated dyes.

Main Methods:

• Single-crystal X-ray diffraction analysis was employed to determine the structures.
• The study involved s-block metals including Sodium (Na), Calcium (Ca), Magnesium (Mg), and Barium (Ba).
• Comparative analysis with existing literature on monosulfonated monoazo dyes was performed.

Main Results:

• Five distinct structures were determined: poly[di-μ-aqua-diaqua[μ4-3,3'-(diazane-1,2-diyl)bis(benzenesulfonato)]disodium(I)], catena-poly[[tetraaquacalcium(II)]-μ-3,3'-(diazane-1,2-diyl)bis(benzenesulfonato)], catena-poly[[[diaquacalcium(II)]-μ-2-(4-amino-3-sulfonatophenyl)-1-(4-sulfonatophenyl)diazenium] dihydrate], hexaaquamagnesium bis[2-(4-amino-3-sulfonatophenyl)-1-(4-sulfonatophenyl)diazenium] octahydrate, and poly[[{μ2-4-[2-(4-amino-2-methyl-5-methoxyphenyl)diazen-1-yl]benzene-1,3-disulfonato}di-μ-aqua-diaquabarium(II)] dihydrate].
• Compound (III) corresponds to the commercial dyestuff Acid Yellow 9.
• Structures range from 0D ion-pairs (Mg) to 1D (Ca, Na), 2D (Ba), and 3D (Na) coordination polymers, with metal atoms coordinating to sulfonate groups.

Conclusions:

• Disulfonation significantly influences the coordination polymer dimensionality compared to monosulfonated analogs.
• Compounds (I) and (II) exhibit structural similarities to monosulfonated species, while (III), (IV), and (V) show distinct structural types.
• The study provides insights into the structure-property relationships of metal-dye complexes.