From Molecular to Two-Dimensional Anderson Polyoxomolybdate: Synthesis, Crystal Structure, and Thermal Behavior of [{Ni(H2O)4}2{Ni(OH)6Mo6O18}]·4H2O and [Ni(H2O)6][Ag2{Ni(OH)6Mo6O18}]·8H2O

✍ Scribed by Feng-Xian Liu; Catherine Marchal-Roch; Damien Dambournet; Aloïs Acker; Jérome Marrot; Francis Sécheresse

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 739 KB
• Volume: 2008
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/ejic.200701288

✦ Synopsis

Abstract

Two 2D Anderson polyoxomolybdate‐based compounds, [{Ni(H~2~O)~4~}~2~{Ni(OH)~6~Mo~6~O~18~}]·4H~2~O (1) and [Ni(H~2~O)~6~][Ag~2~{Ni(OH)~6~Mo~6~O~18~}]·8H~2~O (2), were synthesized and characterized by elemental analysis, IR spectroscopy, SEM, and single‐crystal XRD. Their thermal behavior was studied by TGA, DSC, XRTD, and IR spectroscopy. Both 1 and 2 are arranged in 2D networks. In 1, [Ni(OH)~6~Mo~6~O~18~]^4–^ Anderson units are covalently linked to each other by two different types of Ni^2+^, whereas in 2, the corresponding interactions are ensured exclusively by Ag^+^ ions. In addition, all the Ni^2+^ cations in 2 are located in interplanar positions and act selectively as counterions. Upon the addition of silver, the thermal stability of the Anderson anion is increased from 170 °C for pure nickel compound 1 up to 220 °C for mixed silver–nickel 2. Below 220 °C, 2 exhibits reversible hydration–dehydration processes with preservation of the Anderson anion structure. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)