title: Reactivity of tris(acetylacetonato) iron(III) with tridentate [ONO] donor Schiff base as an access to newer mixed-ligand iron(III) complexes.
abstract: Two new mixed-ligand iron(III) complexes, [Fe(L(n))(acac)(C(2)H(5)OH)] incorporating coordinated ethanol from the reaction solvent were accessed from the reaction of [Fe(acac)(3)] with [ONO] donor dibasic tridentate unsymmetrical Schiff base ligands derived from condensation of 2-hydroxy-1-napthaldehyde with 2-aminophenol (H(2)L(1)) or 2-aminobenzoic acid (H(2)L(2)). The thermal study (TGA-DTA) provided evidence for weakly bound ethanol which is readily substituted by neutral N-donor molecule imidazole, benzimidazole or pyridine to produce an array of newer complexes, [Fe(L(n))(acac)X] (n=1, 2; X=Im, Bim, Py). The compounds were characterized by elemental analyses, FT-IR, UV-vis, solution electrical conductivity, FAB mass, (1)H and (13)C NMR spectroscopy. Room temperature magnetic susceptibility measurements (μ(eff)∼5.8 B.M.) are consistent with spin-free octahedral iron(III) complexes. Cyclic voltammetry of ethanol complexes revealed a quasi-reversible one electron redox response (ΔE(p)>100 mV) for the Fe(III)/Fe(II) couple. Low half wave redox potential (E(1/2)) values suggested easy redox susceptibility. The ground state geometries of the ethanol and imidazole complexes have been ascertained to be distorted octahedral by density functional theory using DMol3 program at BLYP/DNP level.
authors.affiliation: Department of Chemistry, Assam University, Silchar 788011, Assam, India. crbhattacharjee@rediffmail.com
authors.forename: Chira R
authors.initials: CR
authors.lastname: Bhattacharjee
authors.forename: Pankaj
authors.initials: P
authors.lastname: Goswami
authors.forename: Harun A R
authors.initials: HA
authors.lastname: Pramanik
authors.forename: Pradip C
authors.initials: PC
authors.lastname: Paul
authors.forename: Paritosh
authors.initials: P
authors.lastname: Mondal
mesh_terms: D055664:Electrochemical Techniques; D004583:Electrons; D005290:Ferric Compounds / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics; D013058:Mass Spectrometry; D011789:Quantum Theory; D012545:Schiff Bases / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013818:Thermogravimetry
chemical_list: D005290:Ferric Compounds; D008024:Ligands; D012545:Schiff Bases; D007501:Iron