Electrochemical and Structural Characterization of Soft Landed Tungsten‐Substituted Lindqvist Polyoxovanadate‐Alkoxides

Abstract

Lindqvist polyoxovanadate‐alkoxide (POV‐alkoxide) clusters are excellent candidates for applications in energy storage and conversion due to their rich electrochemical profiles. One approach to tune the redox properties of these cluster complexes is through substitutional cationic doping within the hexavanadate core. Here, we report the synthesis of a series of tungsten‐substituted POV‐alkoxide clusters with one and two tungsten atoms. Soft landing of mass‐selected ions was used to purify heterometal POV‐alkoxides that cannot be readily separated using conventional approaches. The soft landed POV‐alkoxides are characterized using infrared reflection‐absorption spectroscopy and electrospray ionization mass spectrometry. The redox properties of the isolated ions are examined using an in situ electrochemical cell which enables traditional in vacuo electrochemical measurements inside of an ion soft landing instrument. Although the overall cluster core retains redox activity after tungsten doping, vanadium‐based redox couples (VV/VIV) are shifted substantially, indicating a pronounced effect of a heteroatom on the electronic structure of the core.

Computation of 31P NMR chemical shifts in Keggin−based lacunary polyoxotungstates

“…Polyoxometalates (POMs) are a large group of discrete, polynuclear metal-oxo clusters comprised of early transition-metal (addenda) and oxide atoms. [1][2][3][4][5][6] Addenda atoms are fully oxidized to d 0 electron configurations capable of forming various topologies employing {MO x } as the principal building block. [1][2][3][4][5][6] Polyoxo clusters are formed from the one-pot acidification of aqueous molybdate or tungstate oxoanions.…”

“…[1][2][3][4][5][6] Addenda atoms are fully oxidized to d 0 electron configurations capable of forming various topologies employing {MO x } as the principal building block. [1][2][3][4][5][6] Polyoxo clusters are formed from the one-pot acidification of aqueous molybdate or tungstate oxoanions. [6][7][8] Self-assembly can be controlled by several synthetic variables including but not limited to: (i) concentration/type of metal oxide anion; (ii) pH and type of acid; (iii) presence of reducing agent; (iv) heteroatom concentration; (v) and solvent.…”

“…[1][2][3][4][5][6] Polyoxo clusters are formed from the one-pot acidification of aqueous molybdate or tungstate oxoanions. [6][7][8] Self-assembly can be controlled by several synthetic variables including but not limited to: (i) concentration/type of metal oxide anion; (ii) pH and type of acid; (iii) presence of reducing agent; (iv) heteroatom concentration; (v) and solvent. [6][7][8][9][10] The synthesis and self-assembly mechanism of POMs requires a complex network of interdependent reactions, in which any slight variation to the listed five experimental variables can change the dominant species of the combinatorial library.…”

Heterometal Dopant Changes the Mechanism of Proton-Coupled Electron Transfer at the Polyoxovanadate-Alkoxide Surface

“…To this end, we became interested in leveraging our expertise in the manipulation of the metal composition of POV-alkoxides to model the impact of heterometal dopants on H-atom uptake at metal oxide surfaces. − Heterometal dopants have been shown to impact lattice geometries and electronic structures of metal oxides, dictating the reactivity at the solution–solid interface . Specifically, these dopants cause geometric strain across the lattice, activating the neighboring oxide moieties.…”