Yb3+ can be much better than Dy3+: SMM properties and controllable self-assembly of novel lanthanide 3,5-dinitrobenzoate-acetylacetonate complexes

Abstract

The first representatives of the binuclear lanthanide 3,5-dinitrobenzoate–acetylacetonate complexes, namely isostructural compounds [Ln(dnbz)(acac)₂(H₂O)(EtOH)]₂ (Ln = Eu (1), Gd (2), Tb (3), Dy (4), Ho (5), Er (6), Tm (7), and Yb (8); dnbz – 3,5-dinitrobenzoate anion; acac – acetylacetonate (pentane-2,4-dionate) anion) were prepared and characterized. The SMM behavior of the Yb compound 8 was shown to be surprisingly less sensitive to the composition of the Yb³⁺ coordination environment in comparison with that of the Dy derivative. For Yb compound 8, the anisotropy barrier is Δ_eff/k_B = 26 K under the dc field of 2000 Oe. This value is the highest one currently known for binuclear Yb complexes.