A Mixed Valence Co(II)Co(III)(2) Field-Supported Single Molecule Magnet: Solvent-Dependent Structural Variation

One-pot reaction of the Schiff base N,N’-ethylene bis(salicylaldimine) (H(2)L), CoCl(2).6H(2)O, and [Ph(2)SnCl(2)] in acetone produces the mixed valence Co(II)Co(III)(2) compound [Co(II)Co(III)(2)(μ-L)(2)(Ph)(2)(μ-Cl)(2)]·(CH(3))(2)CO·H(2)O (1). Our recent study already revealed that the same reaction mixtures in methanol or ethanol produced a heterometallic Sn(IV)Co(III) (2) or monometallic Co(III) complex (3), respectively. Comparison of these organometallic systems shows that the 2,1-intermetallic Ph shift occurs in any of those solvents, but their relevant structural features (mononuclear, dinuclear-heterometallic, and trinuclear mixed valence) are solvent dependent. Geometrical structural rotation is also discussed among the related organometallic Co(II)Co(III)(2) systems. The AC magnetic susceptibility measurements indicate that 1 is a single molecule magnet (SMM), exhibiting a field-induced slow magnetic relaxation with two modes. The relaxation time for the low-frequency channel is as slow as τ~0.6 s at T = 2.0 K and B(DC) = 1.0 T.