ELECTRONIC ABSORPTION-SPECTRA OF THE IRON(II) COMPLEXES OF 2,2'-BIPYRIDINE, 2,2'-BIPYRIMIDINE, 1,10-PHENANTHROLINE, AND 2,2'-6',2''-TERPYRIDINE AND THEIR REDUCTION PRODUCTS

The iron(II) complexes [Fe(bpy)3]2+ (I), [Fe(bpym)3]2+ (II), [Fe(phen)3]2+ (III), and [Fe(terpy)2]2+ (IV) (bpy, 2,2'-bipyridine; bpym, 2,2'-bipyrimidine; phen, 1,10-phenanthroline; terpy, 2,2':6'2"-terpyridine) were subjected to two (for IV) or three (for I-III) stepwise one-electron electrochemical reductions; the products were studied in situ by solution UV-vis-near-IR spectroscopy. Bands of the reduced species in the UV-vis-near-IR region were observed and assigned to anion ligands. The reductions took place in all cases on individual ligands, the spectra of IV- as well as IV2- showing equivalent features similar to those of [Li]+[terpy]-.