Electrochemistry of Isopoly and Heteropoly Oxometalates

Title: Electrochemistry of Isopoly and Heteropoly Oxometalates

Description:

Abstract The sections in this article are Introduction Definitions General Properties, Literature, and Topics Covered A simplified Overview of the Formation of POMs Fundamental Redox Mechanisms of POMs at Electrodes Electrochemical Reductions of Selected Plenary POMs : α‐[ Si W 12 O 40 ] 4− , α‐[ PW 12 O 40 ] 3− , α‐[ P 2 W 18 O 62 ] 6− , and α‐[ H 2 W 12 O 40 ] 6− Aqueous Media Nonaqueous and Mixed Solvents Quinone/hydroquinone‐like Behaviors in the First Several Reduction Waves of POMs Selected Achievements that Illustrate the Basic Behaviors of Plenary POMs at Electrodes Heterogeneous One‐electron Exchange of α‐[ Si W 12 O 40 ] 4− in Dimethylformamide The Reduction Potential of the One‐electron Wave and the Role of the Central Heteroatom Isomerization upon Reduction POM ‐solvent Interactions as Probed by the Redox Potentials of Two POMs Structure of Electrolyte Solutions As Probed by the Electrochemical Behaviors of POMs Cation and Pressure Effects on the Electrochemistry of 12‐Tungstocobaltate and 12‐Tungstophosphate Ions in Acidic Aqueous Solution Mixed Addenda and Other Substituted POMs Comparison of Valence Trapping in Uniform and Mixed Addenda Plenary POMs Lacunary and Transition Metal–substituted POMs Lacunary POMs Transition Metal–monosubstituted POMs An Interesting Case of Mixing up of Substituent and Tungsten Waves: α 1 ‐ and α 2 ‐[ Fe III ( OH 2 ) P 2 W 17 O 61 ] 7− Sandwich‐type POMs Electron Transfer Behaviors of Multi‐iron Sandwich‐type POMs Electrochemical Probing of Siderophoric Behavior in Sandwich‐type Multi‐iron Wells–Dawson Heteropolytungstates Recent Developments Electrochemistry of a New Family of Wells–Dawson Anions: Semivacant Tungstophosphates and Arsenates [ H 4 XW 18 O 62 ] 7− ( X  =  P or As) Evidence for an Influence of the Dissymmetry on the Voltammetric Behavior of PW 18 : Comparison with P 2 W 18 Recent Achievements in Apparently Direct Multiple Electron Transfers on the First Waves of POMs Electrochemistry of the Multi‐nickel Polyoxoanions [ Ni 6 As 3 W 24 O 94 ( H 2 O ) 2 ] 17− , [ Ni 3 Na ( H 2 O ) 2 ( As W 9 O 34 ) 2 ] 11− , and [ Ni 4 Mn 2 P 3 W 24 O 94 ( H 2 O ) 2 ] 17− Electrochemistry of the Iron(III)‐substituted Keggin Dimer, [ Fe 6 ( OH ) 3 (A‐α‐ Ge W 9 O 34 ( OH ) 3 ) 2 ] 11− Theoretical Approaches Electronic Structures of POMs Explain their Redox Behaviors and the Relative Stability of Reduced Forms An Extended Hückel Calculations Approach to a Qualitative Understanding of the Initial Electron Transfer Site in Dawson‐type POMs Electrocatalysis Basic Concepts of Homogeneous Catalysis of Electrode Reactions Selected Electrocatalysis in Homogeneous Solution Electrocatalytic Reductions Electrocatalytic Oxidations Conclusion Acknowledgment.