Cation Effect on Formation of Preyssler‐type 30‐Tungsto‐5‐phosphate: Enhanced Yield of Na‐encapsulated Derivative and Direct Synthesis of Ca‐ and Bi‐Encapsulated Derivatives

Abstract

The effect of cations in a reaction mixture for the preparation of the Preyssler‐Jeannin‐Pope type 30‐tungsto‐5‐phosphate [P5W30O110Na]14– is investigated. Reaction of phosphate and tungstate with a P/W ratio of ca. 3.9 in an acidic aqueous solution without cations selectively leads to the Dawson‐type 18‐tungsto‐2‐phosphate, [P2W18O62]6–. Amongst all the alkali cations, only Na+ allows formation of the Preyssler‐type polyanion [P5W30O110Na]14–, with an encapsulated Na+ ion, and the product yield can be improved by increasing Na+ amount. The presence of Li+ ions instead results in the Dawson‐type polyanion [P2W18O62]6–, whereas K+, Rb+, and Cs+ selectively result in the Keggin‐type polyanion [PW12O40]3–. An improved synthetic procedure for the Na+‐encapsulated Preyssler‐ion leading to a higher isolated yield is presented. Furthermore, addition of Ca2+ and Bi3+ compounds allows formation of the Ca2+‐ and Bi3+‐encapsulated Preyssler‐type polyanions, [P5W30O110Ca]13– and [P5W30O110Bi]12–, respectively. Furthermore, single‐crystal XRD structure of the Bi3+‐encapsulated Preyssler‐type polyanions, [P5W30O110Bi]12–, is presented for the first time.

Confinement of poly(allylamine) in Preyssler-type polyoxometalate and potassium ion framework for enhanced proton conductivity

“…Single-crystal X-ray diffraction (SXRD) analysis showed that the structure of Preyssler-type POM in I agrees with the previous report ( Fig. 1a, Supplementary Data 1 and Supplementary Figure 3) 30 : A bismuth atom (Bi(III)) with a coordination water, which are disordered between two positions, exists on the principal axis of the doughnut-shape POM with pseudo-D 5h symmetry. The Bi(III) is coordinated by five phosphate oxygens (Bi-O = 2.50−2.73 Å).…”

“…Here we show that a Preyssler-type [Bi( 30 with a low anion charge facilitates the migration of protons by decreasing the electrostatic interactions between POM and protons. In addition, poly(allylamine) (PAA) is utilized as a polymer because (1) amine groups contribute to increase the number of protonation sites and to extend the hydrogen-bonding network, which results in efficient proton transport and (2) PAA would be positively charged by protonation, and structural stability may improve via electrostatic interaction with POM.…”

“…We will report the states and dynamics of protons, water, and polymers in the near future. was synthesized according to a previously reported method 30 . Forty percent aqueous poly(allylamine hydrochloride) solution (m = 5000, 3000, or 1600) was provided from Nittobo Medical Co., Ltd. Allylamine hydrochloride and poly(allylamine hydrochloride) (m = 120,000) were purchased from Kanto Chemical Co. and Alfa Aesar, respectively, and used as received.…”

Cation‐Controlled Assembly of Polyoxotungstate‐Based Coordination Networks

“…As {P 5 W 30 } is typically collected by precipitation with KCl, yielding a mixture of K + ‐ and Na + ‐compensated salts (K 14− x Na x [NaP 5 W 30 O 110 ]), we use ion exchange to obtain the acid Preyssler (H 14 [NaP 5 W 30 O 110 ]), which enables systematic variation of the cations present during framework synthesis/crystallization. First, we show that, by varying the amount of K + present, three different Co 2+ ‐bridged structures can be synthesized.…”

Cation‐Controlled Assembly of Polyoxotungstate‐Based Coordination Networks

“…As {P 5 W 30 } is typically collected by precipitation with KCl, yielding a mixture of K + -and Na [47] we use ion exchange to obtain the acid Preyssler (H 14 [NaP 5 W 30 O 110 ]), [48] which enables systematic variation of the cations present during framework synthesis/crystallization. First, we show that, by varying the amount of K + present, three different Co 2+ -bridged structures can be synthesized.…”