Discrete Arsonate-Grafted Inverted-Keggin 12-Molybdate Ion [MoO(OH)(4-NCH-CHAsO)] and Formation of a Copper(II)-Mediated Metal-Organic Framework.

The discrete inverted-Keggin ion [MoO(OH)(4-NCH-CHAsO)] () has been prepared in an aqueous acidic (pH 0.8) medium by the reaction of MoO with the (4-triazolylphenyl)arsonic acid 4-NCH-CHAsOH under hydrothermal conditions and was isolated as a sodium salt in 21% yield. The exact same reaction in the presence of Cu ions resulted in the neutral metal-organic framework (MOF) Cu[MoO(4-NCH-CHAsO)] () in 68% yield. The inverted-Keggin ion comprises a metal-oxo core, which is capped by four organoarsonate groups, and in , individual polyanions are linked in the solid state by coordination of the Cu ions with the triazolyl groups. The discrete ion was characterized by single-crystal X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and atomic absorption (AA) spectroscopy, as well as thermogravimetric analysis (TGA), and the POM-MOF was characterized by single-crystal and powder XRD, FT-IR, TGA, and gas sorption. has channels with a diameter of around ∼0.9 nm and exhibits a water-vapor adsorption capacity of 89.7 cm g (/ = 0.95).