Preparation and separation of mixed-ligand Fe(II) complexes containing 1,10-phenanthroline-5,6-dione as ligand

Abstract

The synthesis, separation, and characterization of mixed-ligand iron(II) complexes containing 1,10-phenanthroline (phen), 1,10-phenanthroline-5,6-dione (pdon), and NCS À are reported. The mixed-ligand complexes [Fe(phen)(pdon) 2 ] 2þ and [Fe(phen) 2 (pdon)] 2þ were prepared from iron(II) sulfate hepta hydrate and both ligands. The mixture of both complexes formed regardless the ratio of the ligands or the reaction time; therefore, the complexes were separated successfully on the reversed phase (RP) Develosil RP-Aqueous [C30] 5 mm, 150 Â 4.6 mm column by two different methods. The first method was the ion paired RP chromatography performed under gradient elution with acetonitrile-water containing 0.001 mol L À1 KPF 6 aqueous as mobile phases. The second method was the RP chromatography performed under gradient elution with methanol and water as mobile phases. The gradient elution with watermethanol as eluents was preferred for the semi preparative separations allowing one to use the complexes without further purification upon separation, different than the first method and its variations so far. Three complexes (5, 6, and 7) were characterized by electrospray ionization mass spectrometry, NMR, UV-Vis, and IR.

Substitution Kinetics of [Fe(PDT/PPDT)n(phen)m]2+(n≠m;n,m= 1,2) with 2,2′-Bipyridine, 1,10-Phenanthroline, and 2,2′,6,2″-Terpyridine

“…Burgess and Haines have reported mechanistic aspects of the formation of iron(II)‐cyanide‐phen and related systems. There are also reports of mixed ligand complexes of the type [FeL 2 × 2 ] 2+ and [FeLX 4 ] 2+ (where L = phen or bpy and X = cyanide or oxalate ion and [FeLL′ 2 ] 2+ ) and [FeL 2 L′] 2+ (where L = phen, L′ = phen‐5,6‐dione and 4,7‐dimethyl phen) . In these studies, the focus was on the synthesis of mixed ligand complexes of Fe(II) and their characterization by mass spectroscopy, NMR, UV–visible, and IR studies.…”