The isolation and characterization of some iron(III) complexes with mixed uni-, bi-, and tridentate ligands

Abstract

Ligand substitution in the Fe(diketo) 3 (diketo = the anion of either acetylacetone (Hacac), benzoylacetone (Hbzac), or dibenzoylmethane (Hdbzac), by its 1:1 molar ratio reaction with either pyridine-2,6-dicarboxylic acid (H 2pdc), picolinic acid (Hpc), or with chloroacetic acids (HR; R A, R B, R C = mono-, di-, or trichloroacetate respectively) produced the mixed iron(III) complexes (diketo)Fe(Pdc) (diketo = acac, bzac, or dbzac), (diketo) 2Fe(pc), (diketo = acac or dbzac), and (acac) 2Fe(R)·nH 2O (for R = R A and R C, n =1 and for R = R B, n = 0) respectively. The reaction of the latter (R = R C; 1:1 molar ratio) with either HR(R = R B or R A) afforded the mixed complex (acac)Fe(R C(R B·H 2O and (acac)Fe(R CR A· H 2O respectively, while its reaction with H 2pdc (1:1) led to the formation of (acac)Fe(pdc). The acetylacetonate anion in the complex could be replaced by oxinate and trichloroacetate in its reaction with oxine (1:1) or HR C (1:5), whereas (acac)Fe(pdc) urea was obtained from the reaction of the complex with urea (1:2). The tridentate (pdc), bidentate (diketone, pc, R C, R B, R A, and oxinate) and monodentate (urea, FeO bonding) coordinations of the ligands and the suggested polymerization of the (pdc) mixed ligand complexes are based on anlytical, spectral and magnetic moment evidence.