Here, we expand on the synthesis and characterization of chloride-functionalized polyoxovanadate-alkoxide (POV-alkoxide) clusters, to include the halogenation of mixed-valent vanadium oxide assemblies. These findings build on our previously disclosed results describing the preparation of a mono-anionic chloride-functionalized cluster, [V 6 O 6 Cl(OC 2 H 5 ) 12 ] 1− , by chlorination of [V 6 O 7 (OC 2 H 5 ) 12 ] 2− with AlCl 3 , aimed at understanding the electronic consequences of the introduction of halide-defects in bulk metal oxides ( e.g. VO 2 ). While chlorination of the mixed-valent POV-ethoxide clusters was not possible using AlCl 3 , we have found that the chloride-substituted oxidized derivatives of the Lindqvist vanadium-oxide clusters can be formed using TiCl 3 (thf) 3 with [V 6 O 7 (OC 2 H 5 ) 12 ] n ( n = 1−, 0) or WCl 6 with [V 6 O 7 (OC 2 H 5 ) 12 ] 0 . Characterization of the chloride-containing products, [V 6 O 6 Cl(OC 2 H 5 ) 12 ] n ( n = 0, 1+), was accomplished via 1 H NMR spectroscopy, X-ray crystallography, and elemental analysis. Electronic analysis of the redox series of Cl-doped POV-alkoxide clusters via infrared and electronic absorption spectroscopies revealed all redox events are localized to the vanadyl portion of the cluster, with the site differentiated V III –Cl moiety retaining its reduced oxidation state across a 1.9 V window. These results present new synthetic routes for accessing chloride-doped POV-alkoxide clusters from mixed-valent vanadium oxide precursors.
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Mechanistic insights into polyoxometalate self-assembly in organic solvent: conversion of a cyclic polyoxovanadate-ethoxide to its Lindqvist congener
We report the synthesis of a cyclic hexavanadate polyoxovanadate-alkoxide cluster, [VO(OC2H5)2]6 , and its conversion, under solvothermal conditions, to an oxygen-deficient Lindqvist assembly, [V 6 O 6 (OC 2 H 5 ) 12 ] n ( n = 1−, 0). This study presents insights into the mechanism of organo-functionalized polyoxovandate-alkoxide formation, namely identifying essential intermediates and the source of the central μ 6 -O 2− ligand.
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- Award ID(s):
- 1653195
- PAR ID:
- 10249408
- Date Published:
- Journal Name:
- Chemical Communications
- Volume:
- 56
- Issue:
- 61
- ISSN:
- 1359-7345
- Page Range / eLocation ID:
- 8607 to 8610
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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