Synthesis, structure and magnetism of a one-dimensional silicotungstate array: K3H4Cu0.5{Cu[Cu7.5Si2W16O60(H2O)4(OH)4]2} · 9H2O

A structurally distinct, multi-copper(II)-substituted silicotungstate K3H4Cu0.5{Cu[Cu7.5Si2W16O60(H2O)4(OH)4]2} · 9H2O (1) has been synthesized and characterized by FT-IR spectroscopy, elemental analysis, variable-temperature magnetic measurements, electron spin resonance, and X-ray diffraction. Green crystalline plates of 1 were obtained by the reaction of K8[γ-SiW10O36] · 12H2O with 8 equiv. of Cu(II) in a 50% ethylene glycol solution. A cationic copper center connects the terminal oxygen atoms of neighboring polyanions, resulting in a one-dimensional structure. Magnetic susceptibility measurements indicate weak ferromagnetic superexchange between the Jahn–Teller-distorted S = 1/2 Cu(II) centers.

Graphical abstractA multi-copper polyanion linked into a 1D polymer by Cu(II) centers, K3H4Cu0.5{Cu[Cu7.5 Si2W16O60(H2O)4(OH)4]2} · 9(H2O) (1) has been characterized by X-ray crystallography and several other methods. Variable temperature magnetic measurements reveal a weak ferromagnetic superexchange between Cu(II) centers.Figure optionsDownload full-size imageDownload as PowerPoint slide