Two W-V-Mn-III bimetallic assemblies built by octacyanotungstate(v) and Mn-III Schiff bases: molecular structures and a spin-flop transition

Two W-V-Mn-III bimetallic compounds, [Mn(Cl-salmen)(H2O)(2)]{[Mn(5-Clsalmen)(H2O)](2)[W(CN)(8)]center dot 2H(2)O (1 center dot 2H(2)O) [5-Clsalmen = N,N '-(1-methylethylene)bis(5-chlorosalicylideneiminato) dianion], which contains trinuclear Mn2W and isolated Mn-III moieties, and [Mn(3-MeOsalcy)(H2O)(2)](3)[W(CN)(8)]center dot 2H(2)O (2 center dot 2H(2)O) [3-MeOsalcy = N,N '-(trans-1,2-cyclohexanediylethylene)bis(3-methoxysalicylideneiminato) dianion] molecules were prepared in redox processes and characterized using X-ray analysis and magnetic measurements. Compound 1 is composed of the {[Mn(5-Clsalmen)(H2O)](2)[W(CN)(8)]}(-)trimer, in which two CN groups among eight in [W(CN)(8)](3-) bridge W5+ and two Mn3+ ions and the remaining CN ligands are hydrogen-bonded to water molecules or unbound, and the [Mn(Cl-salmen)(H2O)(2)](+) cation. Subsequently, two water molecules of the isolated cation are subject to hydrogen bonds. For 2, there are no covalent bonds among the subunits and six serial stacks of [Mn(3-MeOsalcy)(H2O)(2)](+) units are all hydrogen-bonded. The many hydrogen bonds found in both complexes eventually lead to three-dimensional networks. The magnetic studies for 1 reveal that antiferromagnetic interactions (J = -5.4 cm(-1)) between W-V and Mn-III centers within the trimer are transmitted via the bridging CN groups. Intermolecular antiferromagnetic couplings (zJ ' = -0.2 cm(-1)) are also observed. The static and dynamic magnetic data of 1 demonstrate the existence of a field-induced spin-flop transition occurring among the clusters and monomeric molecules.