A Mixed‐Addenda Mo/W Organofunctionalised Hybrid Polyoxometalate

Abstract

A mixed‐addenda W/Mo hybrid polyoxometalate cluster – K6[P2W15Mo2O61(POC6H5)2] (1) was synthesised from the condensation of K10[P2W15Mo2O61] and PO3C6H7 under acidic conditions. Single‐crystal X‐ray diffraction confirmed the structure of the hybrid cluster and the presence of two Mo centres in the cap of the lacunary cluster. The electronic effects of metal substitution were studied by cyclic voltammetry, spectroelectrochemistry and electron paramagnetic resonance spectroscopy and supported by density functional theory calculations. Comparing 1 to its tungsten‐only analogue K6[P2W17O61(POC6H5)2] (2), a more positive potential for the first reduction process was induced by the substitution of W for Mo, consistent with a significant lowering of the cluster LUMO energy.

Computational Study into the Effects of Countercations on the [P8W48O184]40– Polyoxometalate Wheel

“…To complete our benchmarking, we also compared the accuracy of our results against work done by Cameron et al, Zhang et al, and Vilà-Nadal and co-workers. , Our results were very close in value to those of Vilà-Nadal and Zhang, and, despite a larger difference in values caused by different computational software, were in good agreement with the Cameron work as well. Our optimization calculations of {P 8 W 48 } and {P 2 W 12 } yielded the nature of the HOMO and LUMO orbitals (Figure ), as well the energy gap between them, , and the molecular electrostatic potentials (MEPs) (Figure ). The HOMOs for both POMs receive their greatest collective atomic contribution from the framework oxygens, specifically the P Y orbitals, located “behind” the heteroatoms in the center of the POM.…”

When Identification of the Reduction Sites in Mixed Molybdenum/Tungsten Keggin-Type Polyoxometalate Hybrids Turns Out Tricky

“…During the final writing of this paper, the synthesis and characterization of the Dawson-type organophosphonate hybrid K 6 [P 2 W 15 Mo 2 O 61 (POC 6 H 5 ) 2 ] has been described, emphasizing the interest in well-defined and not randomly distributed mixed Mo/W POMs. 38 …”

“…While mono- or multivacant POMs have been extensively exploited for the incorporation of extra transition-metal cations (i.e., other than W, Mo, or V) or the preparation of organic–inorganic hybrids, to the best of our knowledge, transition-metal derivatives of K 7 [α-PW 9 Mo 2 O 39 ] or the corresponding K 8 [α-SiW 9 Mo 2 O 39 ] have not been reported. During the final writing of this paper, the synthesis and characterization of the Dawson-type organophosphonate hybrid K 6 [P 2 W 15 Mo 2 O 61 (POC 6 H 5 ) 2 ] has been described, emphasizing the interest in well-defined and not randomly distributed mixed Mo/W POMs …”

“…has been described, emphasizing the interest in well-defined and not randomly distributed mixed Mo/W POMs. 38 Synthesis of K 39 starting from the sodium salt of [HPW 9 O 34 ] 8− . Note that the latter was initially assigned as a B,β-isomer, but lately has been corrected as a A,β-isomer.…”

Molecular Orbital Engineering of Mixed-Addenda Polyoxometalates Boosts Light-Driven Hydrogen Evolution Activity

“…As molecular catalysts, the atomically precise structures of POMs render them ideal models to investigate the structure–property correlations. More importantly, their electronic structures can be readily tuned by choosing appropriate constituent elements (e.g., addenda atoms), metal substitution, and functionalization by organic groups, − leading to different energy positions of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). The adjustment of electronic structures through molecular orbital engineering strategy could undoubtedly affect the catalytic efficiency (e.g., photocatalytic hydrogen evolution activity).…”