Symmetrical and dissymmetrical 2,2′-bis-dipyrrin ligands and Zn(II) binuclear helicates
A strategy for the synthesis of symmetrical and dissymmetrical 2,2′-bisdipyrrin ligands is proposed. It relies on the preparation of derivatives bearing at their periphery reactive groups that are subsequently used for the introduction of functional units leading to a wide range of new ligands. This approach was applied to the carboxylic acid unit and its subsequent transformation into amides using aniline and an aminopyridine derivative. A series of symmetrical and dissymmetrical species has thus been synthesized and characterized in solution as well as in the crystalline state by X-ray diffraction for some of them. Furthermore, the formation of binuclear helicates upon coordination of Zn(II) cations has been explored.