Counterion Interaction and Association in Metal‐Oxide Cluster Macroanionic Solutions and the Consequent Self‐Assembly

Abstract

The interaction between large metal-oxide polyanions and their counterions is unique. Owing to their size disparity, there is a moderate ion-pairing effect and loose distribution of counterions around macroions, which leads to the unique solution behavior and the self-assembly of the macroions in polar solvents, and the counterion exchange capability around macroions. Furthermore, the macroioncounterion interaction also affects the catalytic behavior of the polyoxometalate (POM) clusters. Replacement of func-tionalized cations helps to modify the POM anions through static charge attraction. At the same time, the strong POMcounterion interaction can also lead to counterion-dependent synthesis. Recent developments on theoretical simulations help to understand this interaction at the molecular scale. This review summarizes the chronological progress of the exploration of macroion-counterion interaction (both theoretically and experimentally) and its impact on related research fields.

Surfactant encapsulated palladium-polyoxometalates: controlled assembly and their application as single-atom catalysts

“…A much simpler method is to encapsulate the POMs with surfactants. 16 , 17 The surfactant encapsulated POMs (SEPs) are much easier to recover and show better dispersibility in organic solvents. 18 , 19 Meanwhile, the chemical surrounding of POMs can be easily tuned based on the choice of surfactants.…”

Soluble Heteropolyniobates from the Bottom of Group IA

“…contaminant transport, crystallization and dissolution, self-assembly, electron transfer), [9] and their importance in POM chemistry has also been recognized. [10] PONbs provide a rare model system for investigating these universal aqueous processes. Herein we present a simple addendum to the general synthesis of heteropolyniobates, [11] which provides highlysoluble K + , Rb + , and Cs + heteropolyniobate salts, opening up new possibilities for this emergent branch of POM chemistry.…”

A General Approach to Access Morphologies of Polyoxometalates in Solution by Using SAXS: An Ab Initio Modeling Protocol

“…The sizes and structural features were comparable between models reconstructed from the ab initio modeling and the crystal structures analyzed from XRD. One should note that in both the models of LAL and CH, an appending structure was attached on the side of the main structure, which could result from the condensation of the large organic counter cations around the POMs . The influence of counterions sometimes was prominent when the sizes of the counterions were comparable to that of the POMs.…”