Synthesis, crystal structure and magnetic properties of dinuclear manganese(II) diketonate with cyanopyridine-N-oxide bridging ligands [Mn(hfac) 2(4-cpyNO)] 2

Abstract

The reaction of Mn(hfac) 2 · 2H 2O (hfac, hexafluoroacetylacetonate anion) with 4-cpyNO (4-cyanopyridine-N-oxide) in chloroform results in the formation of a novel mixed-ligand complex [Mn(hfac) 2(4-cpyNO)] 2. X-ray single crystal structure revealed the presence of dinuclear molecules [Mn(hfac) 2(4-cpyNO)] 2. Within the dimer, two manganese(II) ions are in an octahedral environment and are bridged by two 4-cpyNO ligands through oxygen atoms of the N-oxide groups. The magnetic properties of the compound were studied in the temperature range of 2–300 K. The interaction between Mn(II) ions was found to be weakly ferromagnetic with an exchange coupling constant J=0.23 cm −1 in contrast to an antiferromagnetic interaction observed for most compounds with the Mn(II)(μ-O) 2Mn(II) bridging core. Some magneto-structural correlations are discussed.