A mixed valence Co^IIco^III2 field-supported single molecule magnet: Solvent-dependent structural variation

One-pot reaction of the Schiff base N,N’-ethylene bis(salicylaldimine) (H₂L), CoCl₂.6H₂O, and [Ph₂SnCl₂] in acetone produces the mixed valence Co^IICo^III ₂ compound [Co^IICo^III ₂(μ-L)₂(Ph)₂(μ-Cl)₂]·(CH₃)₂CO·H₂O (1). Our recent study already revealed that the same reaction mixtures in methanol or ethanol produced a heterometallic Sn^IVCo^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^IICo^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.