Dinuclear manganese(II) complexes of 2,6-Bis[2-(dialkylamino)ethyliminomethyl]-4-methylphenolate(1–): synthesis, structure, and magnetism

Abstract

2,6-Bis[2-(dialkylamino)ethyliminomethyl]-4-methylphenolate(1–)[alkyl = methyl (L¹) or ethyl (L²)] forms two types of dinuclear manganese(II) complexes [Mn₂L(RCO₂)₂(NCS)](L = L¹ or L², R = CH₃ or C₆H₅) and [Mn₂LCl₃](L = L¹ or L²). The crystal structure of [Mn₂L¹(CH₃CO₂)₂(NCS)]·H₂O·CH₃OH has been determined: monoclinic, space group P2₁/n, a= 17.700(3), b= 12.516(2), c= 15.263(3)Å, β= 107.16(1)° and Z= 4. The X-ray analysis reveals a dinuclear structure bridged by the phenolic oxygen of L¹ and two acetate groups. The thiocyanate group co-ordinates to one Mn, resulting in different co-ordination geometries about the two manganese ions, i.e. trigonal bipyramidal and pseudo-octahedral. Magnetic susceptibility measurements over the temperature range 4.2–300 K indicate weak antiferromagnetic interaction (J=–2 to –5 cm^–1) for [Mn₂L(RCO₂)₂(NCS)] and no appreciable interaction for [Mn₂LCl₃].