Iron Complexes with the Alcoholato Donor‐Rich Ligand 4‐tert‐Butyl‐2,6‐bis(hydroxymethyl)phenol: Synthesis and Characterization of a Tetra‐Anionic Fe2 Complex and a Neutral Fe10Na4 Complex

Abstract

AbstractThe reaction of 4‐tert‐butyl‐2,6‐bis(hydroxymethyl)phenol (H3L) with FeIII ions in methanol in the presence of an excess of NaOH afforded the tetra‐anionic dinuclear complex Na4[(HL)4FeIII2(CO3)]·11MeOH·3H2O (1). Changing the solvent to an ethanol/dme (dme = 1,2‐dimethoxyethane) mixture led to the formation of the decanuclear complex [(HL)12FeIII10Na4(µ4‐O)4(µ3‐OH)2(dme)2(EtOH)2]·2dme·8EtOH (2). The Mössbauer spectra of 1′ and 2 at 80 K are consistent with high spin FeIII sites in distorted octahedral O6 coordination environments. Compound 1 consists of a tetra‐anionic dinuclear iron complex with the unprecedented [FeIII(μ2‐OBz)2(μ2‐CO3)FeIII]2+ core. Compound 2 contains a core of hydrous ferric oxide produced by a modified hydrolysis of FeIII ions in the presence of the ligand. Eight benzyl alcohol groups are located on the surface of 2 leading to a 2D network structure by intermolecular hydrogen bonding. The temperature dependence of the magnetic susceptibilities of 1′ and 2 indicates antiferromagnetic interactions between the ferric ions. The data for 1′ were fitted with J = −4.4 cm−1 and g = 1.98, H = −2JS1S2. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)