Structure and Magnetism of Cyano-Bridged Hetero-Binuclear Complexes RE(dpdo)₂(H₂O)₃Fe(CN)₆·4H₂O (RE˭Gd, Y)

Two heterobinuclear cyano-bridged RE-Fe complexes RE(dpdo)2(H2O)3Fe(CN)6 ·4H2O (RE˭Gd,Y; dpdo=2,2′-Dipyridyl N.N′-Dioxide) were synthesized with identical structure. Gd-Fe complex crystallizes in triclinic crystal system, space group P-1 with a = 10.305(2), b = 12.475(1), c = 13.903(1)Å, α = 85.34(1), β = 88.08(1), γ = 70.54(1)°, V = 1679.6(4) Å3, Z = 2. In Gd-Fe binuclear unit, Gd3± is eight coordinated by one N atom from one CN− group, four O atoms from two bidentate dpdo molecules and three O atoms from water molecules, forming a square anti-prism. Gd and Fe are bridged via one CN− group from Fe(CN)6 3− ion with Gd-Fe separation 5.507(1)Å. The nearest inter-molecular distances of Gd-Fe, Gd-Gd, Fe-Fe are 7.457(1), 7.984(1), and 8.409(1)Å respectively. There are hydrogen bond intra- and inter-molecular connections. The intra-molecular coupling of Gd-Fe is weakly ferromagnetic, meanwhile the interactions between the binuclear units are weakly antiferromagnetic in character.