Aggregation of Giant Cerium–Bismuth Tungstate Clusters into a 3D Porous Framework with High Proton Conductivity

• Published in: Angewandte Chemie International Edition Vol. 57; no. 28; pp. 8416 - 8420
• Main Authors: Liu, Jian‐Cai, Han, Qing, Chen, Li‐Juan, Zhao, Jun‐Wei, Streb, Carsten, Song, Yu‐Fei
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 09.07.2018
• Edition: International ed. in English
• Subjects: Anions; Bismuth; Bismuth compounds; Cerium; Clusters; Conductivity; Crystal growth; Crystal lattices; Electrochemical impedance spectroscopy; Electrochemistry; Low temperature; Materials science; Metal oxides; Metals; Molecular chains; Organic chemistry; polyoxometalates; polyoxotungstate; porous materials; proton conduction; self-assembly; Spectroscopy; Tungstates; X-ray diffraction; polyoxotungstate; self-assembly; proton conduction; porous materials; polyoxometalates
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201803649

The exploration of high nuclearity molecular metal oxide clusters and their reactivity is a challenge for chemistry and materials science. Herein, we report an unprecedented giant molecular cerium–bismuth tungstate superstructure formed by self‐assembly from simple metal oxide precursors in aqueous solution. The compound, {[W14CeIV6O61]([W3Bi6CeIII3(H2O)3O14][B‐α‐BiW9O33]3)2}34− was identified by single‐crystal X‐ray diffraction and features 104 metal centers, a relative molar mass of ca. 24 000 and is ca. 3.0×2.0×1.7 nm3 in size. The cluster anion is assembled around a central {Ce6} octahedron which is stabilized by several molecular metal oxide shells. Six trilacunary Keggin anions ([B‐α‐BiW9O33]9−) cap the superstructure and limit its growth. In the crystal lattice, water‐filled channels with diameters of ca. 0.5 nm are observed, and electrochemical impedance spectroscopy shows pronounced proton conductivity even at low temperature. A giant cerium–bismuth tungstate cluster featuring more than 100 metal ions and a relative molar mass of approximately 24 000 is structurally characterized. The cluster anions form a highly 3D‐porous crystalline lattice featuring water‐filled channels. Proton conductivity measurements show high proton mobility within the framework.