Three-dimensional architectures based on 1:1 type lanthanide-substituted Keggin-type polyoxometalates and lanthanide cations

Multifunctional ZnII–LnIII (Ln = Tb, Dy) complexes based on the amine-phenol ligand with field-induced slow magnetic relaxation, luminescence, and proton conduction

Two new isomorphic Zn^II–Ln^III–Zn^II trinuclear complexes based on the amine-phenol ligand have been prepared.

Cation-Controlled Assembly of Polyoxotungstate-Based Coordination Networks

The Preyssler polyoxoanion, [NaP₅ W₃₀ O₁₁₀ ]^14- ({P₅ W₃₀ }), is used as a platform for evaluating the role of nonbridging cations in the formation of transition-metal-bridged polyoxometalate (POM) coordination frameworks. Specifically, the assembly architecture of Co²⁺ -bridged frameworks is shown to be dependent on the identity and amount of alkali or alkaline-earth cations present during crystallization. The inclusion of Li⁺ , Na⁺ , K⁺ , Mg²⁺ , or Ca²⁺ in the framework synthesis is used to selectively synthesize five different Co²⁺ -bridged {P₅ W₃₀ } structures. The influence of the competition between K⁺ and Co²⁺ for binding to {P₅ W₃₀ } in dictating framework assembly is evaluated. The role of ion pairing on framework assembly structure and available void volume is discussed. Overall, these results provide insight into factors governing the ability to achieve controlled assembly of POM-based coordination networks.

Incorporating polyoxometalates and organic ligands to pursue 3d–4f heterometallic clusters: a series of {Cr4Ln4} clusters stabilized by phthalic acid and [SiW12O40]4−

By introduction of trilacunary Keggin-type polyoxometalate to the hydrothermal reaction system of Cr³⁺, Ln³⁺ and phthalic acid, a series of novel {Cr₄Ln₄} heterometallic clusters with the formula Cs₂[Cr₄Ln₄(μ₄-O)₄(μ₃-O)₄(C₈H₄O₄)₄(H₂O)₁₂](H₃SiW₁₂O₄₀)Cl·23H₂O (1-Ln, Ln = Ce, Pr, Nd) and [Cr₄Ln₄(μ₄-O)₄(μ₃-O)₄(C₈H₄O₄)₄(H₂O)₁₀](H₆SiW₁₂O₄₀)Cl₂·18H₂O (2-Ln, Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er) have been obtained. Single-crystal structural analyses show that 1-Ln and 2-Ln constitute the first cases of Cr–Ln heterometallic clusters stabilized by inorganic polyoxometalate anions and organic ligands. Optical spectra studies demonstrate that 1-Ln and 2-Ln are narrow-gap semiconductors with band gaps of about 1.5 eV. Magnetic investigation shows that compound 2-Dy is a potential single molecule magnet.

By introduction of trilacunary Keggin-type polyoxometalate to the hydrothermal reaction system of Cr³⁺, Ln³⁺ and phthalic acid, a series of novel {Cr₄Ln₄} heterometallic clusters have been obtained.