Synthesis, structure and electrochemical characterization of an isopolytungstate (W4O16) held by MnII anchors within a superlacunary crown heteropolyanion {P8W48}

Masooma Ibrahim; Israël M Mbomekallé; Pedro de Oliveira; George E Kostakis; Christopher E Anson

doi:10.1039/c9dt02478f

Synthesis, structure and electrochemical characterization of an isopolytungstate (W₄O₁₆) held by Mn^II anchors within a superlacunary crown heteropolyanion {P₈W₄₈}

Dalton Trans. 2019 Nov 7;48(41):15545-15552. doi: 10.1039/c9dt02478f. Epub 2019 Jul 24.

Authors

Masooma Ibrahim¹, Israël M Mbomekallé², Pedro de Oliveira², George E Kostakis³, Christopher E Anson⁴

Affiliations

¹ Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany. masooma.ibrahim@kit.edu.
² Equipe d'Electrochimie et Photo-électrochimie, Laboratoire de Chimie Physique, Université Paris-Sud, UMR 8000, CNRS-Université Paris Saclay, Orsay F-91405, France.
³ Chemistry Department, University of Sussex, Sussex House, Falmer Brighton, BN1 9RH UK.
⁴ KIT, Institute of Inorganic Chemistry, 76131 Karlsruhe, Engesserstrasse 15, D-76131, Karlsruhe, Germany.

PMID: 31339139
DOI: 10.1039/c9dt02478f

Abstract

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 Mn^II cations as anchors, whereas the exocyclic coordination of four further Mn^II 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 Mn^II ions (largest) coordinated to the inner side of the crown ring as anchors.