Syntheses, structures and magnetic properties of two unprecedented hybrid compounds constructed from open Wells–Dawson anions and high-nuclear transition metal clusters

Abstract

Two new inorganic–organic hybrid compounds Na₂(C₃N₂H₁₂)₄{[Ni₅(OH)₃(H₂O)₄(CH₃CO₂)][Si₂W₁₈O₆₆]}·12.5H₂O (1) and (C₃N₂H₁₂)₃{[Co^II₂Co^III₄(OH)₅(H₂O)₂(CH₃CO₂)][Si₂W₁₈O₆₆]}·6H₂O·(C₃N₂H₁₀) (2), based on lacunary polyoxometalates and high-nuclear transition-metal clusters, have been synthesized by a new method (solvothermal method). Single crystal XRD, magnetic measurements, nonlinear-optical (NLO) measurements, thermogravimetric (TG) measurements, and IR spectra were performed to analyze the structures and properties of 1 and 2. XRD analyses reveal that compound 1 consists of an open Wells–Dawson anion [Si₂W₁₈O₆₆]¹⁶⁻, a five-nuclear cationic cluster [Ni₅(OH)₃(H₂O)₄(CH₃CO₂)]⁶⁺, free Na⁺ cations, and protonated 1,3-diaminopropanes. Compound 2 has a similar structure to 1, while a six-nuclear cationic cluster [Co^II₂Co^III₄(OH)₅(H₂O)₂(CH₃CO₂)]¹⁰⁺ replaces the five-nuclear cationic cluster [Ni₅(OH)₃(H₂O)₄(CH₃CO₂)]⁶⁺ in 1. Magnetic susceptibility measurements indicate antiferromagnetic interactions in 1, and the chirality of compound 2 may bring potential properties of catalysis and optical nonlinearity.