Isomeric effects on the acidity of Al₁₃ Keggin clusters in porous ionic crystals

Abstract

We demonstrate a facile synthesis method of a porous ionic crystal (PIC) composed of the little-known δ-Keggin-type cationic polyoxoaluminum cluster ([δ-Al13O4(OH)24(H2O)12]7+, δ-Al13) with an oppositely-charged polyoxometalate, which enabled us to...

Oxygen Evolution Reaction Driven by Charge Transfer from a Cr Complex to Co-Containing Polyoxometalate in a Porous Ionic Crystal

“…The incorporation of Co-POMs into ionic polymers as well as MOFs , constructs nanocomposites with improved stabilities and high OER activities due to synergistic effects among the building blocks. From this perspective, porous ionic crystals (PICs) composed of POMs and macrocations (e.g., oxo-centered trinuclear metal carboxylates [M III 3 O­(OOCR) 6 (L) 3 ] + ), which are emerging crystalline nanocomposites, − can be considered promising candidates for OER catalysts. Specifically, catalytically active sites can be incorporated beforehand into the molecular building blocks, and these functions can be utilized as PICs because the building blocks exist as discrete molecules in the crystal lattice.…”

Polyoxocationic antimony oxide cluster with acidic protons

“…Contrary to the negatively charged POMs, positively charged metal-oxo clusters (metal-oxo polycations) are quite rare (9,10), but in recent years, special attention has been paid to the development of the synthesis of cationic metal-oxo clusters (11)(12)(13)(14)(15) (18,19), and isolation of these clusters. While applications ranging from water purification to catalysis have been searched for Al 13 and its analogs (20)(21)(22), the research on cationic metal-oxo clusters, in general, is in its infancy, and most studies focus on the synthetic and structural aspects, while their functions remain practically unexplored. Thus, the finding of a previously unknown cationic metal-oxo clusters not only provides a structural impact of its own but also promises unique functions in a solution or as various complexes when combined with negatively charged counter anions.…”

Vanadium-substituted polycationic Al-oxo cluster in a porous ionic crystal exhibiting Lewis acidity

“…We note that the actual positions of V atoms in PW 9 V 3 could not be determined due to the V/W substitutional disorder. 9,11 in which d-Al 13 and PW 9 V 3 were arranged alternately by electrostatic interactions and hydrogen bonds to form 1D-channels along the b-axis (Fig. S3, ESI †).…”

“…8 While the ε-Al 13 isomer is the most thermodynamically favored, the more reactive δ-Al 13 isomer has received much attention. For instance, δ-Al 13 exhibits high catalytic activity in acid reactions 9 and has been utilized as a building block to construct an array of large clusters such as [Al 26 O 8 (OH) 50 (H 2 O) 20 ] 12+ ( Al 26 ), [Al 30 O 8 (OH) 56 (H 2 O) 26 ] 18+ ( Al 30 ), and [Al 32 O 8 (OH) 60 (H 2 O) 28 (SO 4 ) 2 ] 16+ ( Al 32 ). 10–13 Recently, metal-substitution in δ-Al 13 has been proposed as a promising approach to explore the structural diversity of the clusters.…”

“…In a typical synthesis, an aqueous solution of δ-Al 13 was first prepared by heating AlCl 3 and NaOH in distilled water at 368 K. 9 The δ-Al 13 solution was mixed with an aqueous solution of potassium salt of PW 9 V 3 ( K 6 PW 9 V 3 ) and heated at 353 K for 1 week in an oven using a low-temperature hydrothermal method to grow orange octahedral-shaped crystals of Al 28 V 4 -PW 9 V 3 . Note that K 6 PW 9 V 3 acts as a V 5+ source for Al 28 V 4 and a counter anion of Al 28 V 4 .…”