A Series of Vanadogermanates from 1D Chain to 3D Framework Built by Ge–V–O Clusters and Transition-Metal-Complex Bridges

摘要

Three novel extended vanadogermanates, {[(en)₂Cd₂Ge₈V₁₂O₄₀(OH)₈(H₂O)][Cd(en)₂]₂}6 H₂O (1), {[Zn₂(dap)₃][Zn(dap)]₂Ge₆V₁₅O₄₈(H₂O)}[Zn(dap)₂(H₂O)]₂3 H₂O (2), and {[Cd₃(μ-dien)₂(Hdien)₂(H₂O)₂]Ge₄V₁₆O₄₂(OH)₄(H₂O)}2 H₂O (3; en=ethylenediamine, dap=1,2-diaminopropane, dien=diethylenetriamine), have been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, powder XRD, thermogravimetric analysis, and single-crystal XRD. Their Ge–V–O cluster anions are derived from the V₁₈O₄₂ cluster shell by replacing VO₅ square pyramids with Ge₂O₇ groups. Compound 1 exhibits a 1D sinusoidal chain built up from rare inorganic–organic hybrid dicadmium-substituted vanadogermanate {[Cd(en)]₂V₁₂O₄₀(GeOH)₈(H₂O)} clusters and [Cd(en)₂] complexes. Compound 2 is the first example of a 2D network based on linkage of the unusual {Ge₆V₁₅O₄₈(H₂O)} clusters and two types of Zn complex fragments. Compound 3 is an unprecedented 3D framework built by {Ge₄V₁₆O₄₂(OH)₄(H₂O)} clusters and rare trinuclear bridging complex cations [Cd₃(μ-dien)₂(Hdien)₂(H₂O)₂]8+. Magnetic measurements illustrate that both 1 and 2 have antiferromagnetic exchange interactions between metal centers, whereas 3 exhibits ferrimagnetic behavior, which is rare in polyoxovanadate complexes.