Thio-azo proligands based on 5,6-derivatives-1,10-phenanthroline and their use for iron(II) complexes: Synthesis, characterization and crystal structures

The preparation and characterization of 5,6-substituted-1,10-phenanthrolines, phdtos = 5,6-bistosyl-1,10-phenanthroline (1) and phdbt = 5,6-dibenzyltiol-1,10-phenanthroline (2) are described. The synthesis of (1) was achieved in good yield via the corresponding dihydroxide and 2 was obtained by cross-coupling reaction of 5,6-dibromo-1,10-phenanthroline and benzylthiol mediated by a palladium catalytic system in refluxing toluene (120 °C). These phenanthroline derivatives were used as ligands to afford [FeII(phdtos)3](PF6)2 (5) and [FeII(phdbt)3](PF6)2 (6) complexes.

Graphical abstractTwo 5,6-substituted-1,10-phenanthroline ligands have been prepared and characterized. Theses two compounds can be direct precursors of 5,6-dithiolate-1,10-phenanthroline, which is an attractive thio-azo ligand. The diimine coordination ability of the proligands was explored with the synthesis of two FeII(L)3 complexes.Figure optionsDownload full-size imageDownload as PowerPoint slide