Zinc(II)-pyridylthioazophenol system: synthesis, characterization and crystal structure

Abstract

Reactivities of pyridylthioazophenols (1) with zinc(II) salts have been studied and the complexes isolated in pure form and characterized. Pyridylthioazophenols react with zinc(II) acetate in MeOH/EtOH at room temperature to give a series of pyridylsulfinylazophenols (2) but no zinc(II) complex. The sulfoxides (2) have been characterized by IR and NMR. One of the pyridylsulfinylazophenols (2a) has been subjected to single-crystal X-ray analysis in order to confirm details of its structure. A series of dimeric zinc(II) complexes of tetradentate NSNO pyridylthioazophenolates has been isolated through reaction of zinc nitrate in MeOH followed by in situ reaction with azide ion, which acts as a μ-(1, 1) bridge. All complexes have been characterized spectroscopically. The detailed structure of one of the dinuclear zinc(II) complexes has been established by a single-crystal X-ray structure determination. In complex 3a two octahedrally coordinated zinc(II) ions are bridged by two end-on azide ions. No reactions of pyridylthioazophenols with zinc chloride in refluxing EtOH have been observed.

Keywords:

• Zinc(II)
• Pyridylthioazophenols
• Pyridylsulfinylazophenols
• Crystal structure

Acknowledgements

Financial support from the Department of Science and Technology (DST) and Council of Scientific and Industrial Research (CSIR), New Delhi, India, is gratefully acknowledged. We thank EPSRC and the University for Reading for funds for the Image Plate System.