A Mixed Valence CoIICoIII2 Field-Supported Single Molecule Magnet: Solvent-Dependent Structural Variation

One-pot reaction of the Schiff base N,N'-ethylene bis(salicylaldimine) (H2L), CoCl2 center dot 6H(2)O, and [Ph2SnCl2] in acetone produces the mixed valence (CoCo2III)-Co-II compound [(CoCo2III)-Co-II(mu-L)(2)(Ph)(2)(mu-Cl)(2)]center dot(CH3)(2)CO center dot H2O (1). Our recent study already revealed that the same reaction mixtures in methanol or ethanol produced a heterometallic (SnCoIII)-Co-IV (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 (CoCo2III)-Co-II 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 tau similar to 0.6 s at T = 2.0 K and B-DC = 1.0 T.

Automated summary

The reaction of Schiff base N,N'-ethylene bis(salicylaldimine), CoCl2·6H2O, and [Ph2SnCl2] in acetone produces a mixed valence compound. The structural features of the resulting organometallic systems are dependent on the solvent used. Compound 1 exhibits slow magnetic relaxation behavior and is classified as a single molecule magnet.