New plenary and lacunary polyoxotungstate structures assembled from nonatungstoarsenate(III) anions and uranyl cations
Abstract
A new structural family of heteropolytungstate complexes containing trans-dioxo uranium(VI) (uranyl) groups has been isolated in good yield by reaction of UO22+ with [NaAs4W40O140]27− (W40) in aqueous solution. The “lacunary” anion, [(UO2)3(H2O)5As3W29O104]19−1 is formed by the reaction of W40 with UO2(MeCO2)2 at pH 7, and the crystal structure of (NH4)19[(UO2)3(H2O)5As3W29O104]·28H2O [orthorhombic, P212121, a = 17.5626(2), b = 24.4929(2), c = 33.3019(3) Å] is reported. The “plenary” anion, [(UO2)3(H2O)6As3W30O105]15−2 is formed by reaction of W40 with UO2(NO3)2 at pH 4, and the crystal structure of (NH4)15[(UO2)3(H2O)6As3W30O105]·20H2O [monoclinic, P21/c, a = 23.63520(10), b = 18.0646(2), c = 35.32640(10) Å, β = 107.46°] is reported. Both heteropolyanions contain three B-AsW9O339− groups linked by uranyl