Bisphenolate iron(II) complexes with intramolecularly coordinating nitrogen Lewis bases

The synthesis and characterisation of a novel Fe(II) bisphenolate complex [Fe(OC6H4CH2NMe2-2)(2)](2) (1) from [Na(OC6H4CH2NMe2-2)] and anhydrous FeCl2 is reported. The solid state structure has been elucidated by single crystal X-ray analysis and shows a dimeric structure with two bridging and two terminal phenolate ligands. Compound 1 reacts with pyridine to form the adduct [Fe(OC6H4CH2NMe2-2)(2)(py)(2)] (2). Similarly, 2 equiv. of [Na(OC6H2(CH2NMe2)(2)-2,6-Me-4)] were reacted with FeCl2 and the thus in situ prepared '[Fe(OC6H2(CH2NMe2)(2)-2,6-Me-4)(2)](n)' (3) was reacted with pyridine to form the adduct [Fe(OC6H2(CH2NMe2)(2)-2,6-Me-4)(2)(pyr)(2)] (4). Compound 4 was characterised by single crystal X-ray analysis. Attempts to use these compounds as catalysts in the oxidation of cyclohexane with t-butylhydroperoxide (cat.:C6H12:t-BuOOH = 1:1000:100) resulted in the direct formation of brown coloured products, probably as a result of irreversible oxidation of 1, 2, 3 and 4, respectively. No cyclohexanol or cyclohexanone was formed. (C) 1999 Elsevier Science S.A. All rights reserved.