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Updated: Nov 25, 2025

Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments
Published on: May 11, 2017
Aluminum-Substituted Keggin Germanotungstate [HAl(H2O)GeW11O39]4-: Synthesis, Characterization, and Antibacterial
Elias Tanuhadi1, Nadiia I Gumerova1, Alexander Prado-Roller2
1Universität Wien, Fakultät für Chemie, Institut für Biophysikalische Chemie, Althanstrasse 14, 1090 Wien, Austria.
Abstract:
We report on the new monosubstituted aluminum Keggin-type germanotungstate (C4H12N)4[HAlGeW11O39(H2O)]·11H2O ([Al(H2O)GeW11]4-), which has been synthesized at room temperature via rearrangement of the dilacunary [γ-GeW10O36]8- polyoxometalate precursor. [Al(H2O)GeW11]4- has been characterized thoroughly both in the solid state by single-crystal and powder X-ray diffraction, IR spectroscopy, thermogravimetric analysis, and elemental analysis as well as in solution by cyclic voltammetry (CV) 183W, 27Al NMR and UV-vis spectroscopy. A study on the antibacterial properties of [Al(H2O)GeW11]4- and the known aluminum(III)-centered Keggin polyoxotungstates (Al-POTs) α-Na5[AlW12O40] (α-[AlW12O40]5-) and Na6[Al(AlOH2)W11O39] ([Al(AlOH2)W11O39]6-) revealed enhanced activity for all three Al-POTs against the Gram-negative bacterium Moraxella catarrhalis (minimum inhibitory concentration (MIC) up to 4 microg mL-1) and the Gram-positive Enterococcus faecalis (MIC up to 128 microg mL-1) compared to the inactive Al(NO3)3 salt (MIC > 256 microg mL-1). CV indicates the redox activity of the Al-POTs as a dominating factor for the observed antibacterial activity with increased tendency to reduction, resulting in increased antibacterial activity of the POT.
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