I. Mbomekallé, P. de Oliveira et leurs collaborateurs ont publié un article récemment dans Dalton Transactions :
"Synthesis, structure and electrochemical characterization of an isopolytungstate (W4O16) held by MnII anchors within a superlacunary crown heteropolyanion P8W48"
Résumé
An isopolyanion W4O16 within an archetypal P8W48 heteropolyanion assembly [(P8W48O184)(W4O16)K10Li4Mn10Na(H2O)50Cl2]15− (Mn10W4-P8W48) has been synthesized by the reaction of the cyclic superlacunary anion [H7P8W48O184]33− and Mn(ClO4)2·6H2O in 1 M LiCl solution medium at pH 8. The isolated compound has been characterized by single-crystal X-ray crystallography, powder X-ray diffraction (PXRD), Fourier-transform infrared (FTIR) spectroscopy, elemental analysis and thermogravimetric analysis. Electrochemical studies were also performed on Mn10W4-P8W48, which confirmed the presence of Mn centres bonded to the tungstic framework. The novel polyanion [(P8W48O184)(W4O16)K10Li4Mn10Na(H2O)50Cl2]15− is the first example of a macrocyclic complex, where an isopolyanion (W4O16)8− is embedded within the inner cavity of P8W48 and is placed in position by six MnII cations as anchors, whereas the exocyclic coordination of four further MnII cations to P8W48 yields an extended structure by linking neighbouring polyanions through W–O–Mn–O–W bridges. Furthermore, the polyanion Mn10W4-P8W48 is the first derivative of P8W48 with six MnII ions (largest) coordinated to the inner side of the crown ring as anchors.