New Path for Polyoxometalates: Controlled Synthesis and Characterization of Metal‐Substituted Tungstosulfates

• Published in: European journal of inorganic chemistry Vol. 2020; no. 8; pp. 682 - 689
• Main Authors: Hirabaru, Hikaru, Kawamoto, Daisuke, Ohnishi, Miho, Ota, Hiromi, Sadakane, Masahiro, Yanagisawa, Kazumichi, Hasegawa, Takuya, Ueda, Tadaharu
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 28.02.2020
• Subjects: Aqueous solutions; Chemical properties; Copper; Crystallography; Inorganic chemistry; Manganese; Metal substitution; Molecular structure; Nickel; Organic chemistry; Polyoxometalates; Polyoxometallates; Substitutes; Synthesis design; Tungsten; Wells‐Dawson compounds
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201901298

Currently, a large number of metal‐substituted tungstophosphates and tungstosilicates have been prepared with well‐controlled systematic procedures, and many of them have been applied to various fields, such as catalysis and materials, because of their fascinating chemical properties. In addition, the diverse structures of metal‐substituted polyoxometalates (POMs) are quite interesting as molecular architectures. However, there have been fewer reports on the synthesis of metal‐substituted POMs with other hetero atoms. In the present study, controlled and systematic synthetic procedures for Wells–Dawson‐type metal‐substituted tungstosulfates, [S2MW17O61]6– (M = Mn, Co, Ni, Cu), were developed via a ring‐shaped lacunary tungstosulfate, [(S2W14O54)3]32– prepared from the weak base treatment of K4[S2W18O62] in aqueous solution. [(S2W14O54)3]32– and [S2MW17O61]6– were structurally characterized by elemental analysis, X‐ray crystallography and ESI‐MS. [(S2W14O54)3]32– has a different type of structure with a cavity than Preyssler‐type POMs, [X5W30O110]n–, and the other POMs, [X8W48O184]40– (X = P, As). In addition, IR, Raman and UV/Vis spectra as well as cyclic voltammograms of all of the POMs isolated in the present study were obtained and compared with the corresponding Wells–Dawson‐type metal‐substituted tungstophosphates. The synthetic procedures for [S2MW17O61]6– from [S2W18O62]4– via [(S2W14O54)3]32– could open a new path for tungstosulfate chemistry, such as widespread tungstophosphate and tungstosilicate chemistry. Controlled and systematic synthetic procedures for Wells–Dawson‐type metal‐substituted tungstosulfates, [S2MW17O61]6– (M = Mn, Co, Ni, Cu), were developed via a ring‐shaped lacunary tungstosulfate, [(S2W14O54)3]32–, prepared from the weak base treatment of K4[S2W18O62] in aqueous solution.