Hydrogen-Bond Directed Cyanide-Bridged Molecular Magnets Derived from Polycyanidemetalates and Schiff Base Manganese(III) Compounds: Synthesis, Structures, and Magnetic Properties

Abstract

A series of six new cyanide-bridged heterometallic complexes including two tetranuclear T-like Fe(III)Mn(III)(3) compounds, {[Mn(L(1))(H(2)O)](3)[Fe(CN)(5)(1-CH(3)im)]}ClO(4) x 1.5 H(2)O (1) and {[Mn(L(2))(H(2)O)](3)[Fe(CN)(5)(1-CH(3)im)]}ClO(4) x 3 H(2)O (2); two heptanuclear cage-shaped M(III)Mn(III)(6) (M = Fe, Cr) compounds, {[Mn(L(2))(H(2)O)](6)[Fe(CN)(6)]}[Fe(CN)(6)] x 6 CH(3)OH (3) and {[Mn(L(2))(H(2)O)](6)[Cr(CN)(6)]}[Cr(CN)(6)] x 6 CH(3)OH (4); and two two-dimensional M-Mn(III) networks, {[H(3)O][Mn(L(1))](2)[Fe(CN)(6)]} x 2 DMF (5) and {K[Mn(L(1))](2)[Cr(CN)(6)]} x 1.5 CH(3)CN x CH(3)OH (6) (L(1) = N,N-ethylene-bis(3-methoxysalicylideneiminate, L(2) = N,N-ethylene-bis(3-ethoxysalicylideneiminate) have been successfully assembled from three polycyanidemetalates containing five or six cyanide groups and two manganese(III) building blocks containing bicompartmental Schiff base ligands. The cyanide-bridged polynuclear complexes are self-complementary through a coordinated aqua ligand from one complex and the free O(4) compartment from the neighboring complex, giving supramolecular one-dimensional ladders and three-dimensional networks for 1 and 2 and for 3 and 4, respectively. Investigation over magnetic susceptibilities of the six complexes reveals the overall ferromagnetic interactions for complexes 1, 2, 3, and 5 and antiferromagnetic interaction for 4 and 6. Compounds 1-4 show some characteristics of metamagnet behavior at low temperatures due to the relatively strong intermolecular hydrogen-bonding interaction. The two complexes with two-dimensional structure exhibit three-dimensional antiferromagnetic ordering with typical metamagnetic behavior below 8.4 K for 5 and 11.5 K for 6, respectively. The present result appears to add new members to the very few examples of polynuclear clusters exhibiting 3D magnetic ordering relying on intermolecular interactions, to the best of our knowledge, which will be helpful for providing valuable information for the understanding and application of intermolecular hydrogen-bonding interactions in the molecular magnetic materials.