{Mn2IIILn2III} (Ln = Gd, La or Y) butterfly complexes: Ferromagnetic exchange observed between bis-μ-alkoxo bridged manganese(III) ions

Three tetranuclear {Mn(2)(III)Ln(2)(III)} 'butterfly' complexes with common Mn-2(III) mu 3 -alkoxo bridging motifs surrounded by two Ln(III) ions (Ln = Gd, La or Y) have been studied by structural, magnetic and density functional theoretical calculations. The exchange coupling constant between the body-body Mn(III) ions is ferromagnetic in all cases, the La and Y examples being diamagnetic at the wing-wing positions. The wing-body J(wb) (Mn Gd) interaction is small and negative. Reasons are given for these J(MnMn) values, including the effects of the terminal Ln(III) ions, comparison toanalogous Mn-2 dinuclears, and the effects of spin polarisation. (C) 2019 Elsevier Ltd. All rights reserved.