Extending the Lindqvist Family to Late 3d Transition Metals: A Rational Entry to CoW<sub>5</sub> Hexametalate Chemistry

Errington, R. John; Harle, Gavin; Clegg, William; Harrington, Ross W.

doi:10.1002/ejic.200900640

Cited by 28 publications

(14 citation statements)

References 69 publications

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“…[12] The structures were solved by automatic direct methods and refined by full-matrix least-squares on all unique F 2 values, [13] with hydrogen atoms constrained in ar iding model. Extensive disorder in some of the cations (4,5,6,8,9,10)w as modelled as far as possible with the aid of restraints on geometry and anisotropic displacement parameters, though unresolved disorder clearly remains in some cases;a nions of 2, 8 and 9 have disorder of Sn and Wa tom positions as ac onsequence of crystallographic symmetry.T he structures of 5 and 7,i nn on-centrosymmetric space groups, display partial inversion twinning.…”

Section: Methodsmentioning

confidence: 99%

“…By exploiting the sensitivity of metal alkoxides towards hydrolysis, we have developed non‐aqueous routes to a range of tetrabutylammonium (TBA) salts of heterometallic, Lindqvist‐type {M′M 5 } hexametalates [(RO)M′W 5 O 18 ] n − (M′=Ti, Zr, Hf, Nb, Sn) and [(RO)TiMo 5 O 18 ] n − . Modifications to the methodology also provided access to Co II derivatives [(CoW 5 O 18 H) 2 ] 6− and [(C 5 H 5 N)CoW 5 O 18 H] 3− . The alkoxido‐substituted hexametalates provide a platform for detailed solution reactivity studies as well as systematic access to a wide range of [XM′M 5 O 18 ] 3− derivatives (M=W, M′=Ti, Zr; M=Mo, M′=Ti) .…”

Section: Introductionmentioning

confidence: 99%

“…[2,3] Modifications tot he methodology also provideda ccesst oC o II derivatives [(CoW 5 O 18 H) 2 ] 6À and [(C 5 H 5 N)CoW 5 O 18 H] 3À . [4] The alkoxido-substituted hexametalates provide ap latform for detailed solution reactivity studies as well as systematica ccess to aw ide range of [XM'M 5 O 18 ] 3À derivatives( M= W, M' = Ti,Z r; M= Mo, M' = Ti). [5] Incorporation of these reactives ites also allowed us to achievethe first covalent attachment of aP OM to silicon surfaces.…”

Section: Introductionmentioning

confidence: 99%

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Bonding Insights from Structural and Spectroscopic Comparisons of {SnW₅} and {TiW₅} Alkoxido‐ and Aryloxido‐Substituted Lindqvist Polyoxometalates

Kandasamy

Bruce

Clegg

et al. 2018

Chemistry A European J

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Incorporation of {MX} groups into polyoxometalates (POMs) provides the means not only to introduce reactivity and functionality but also to tune the electronic properties of the oxide framework by varying M, X and n. In order to elucidate the factors responsible for differences in reactivity between {TiW } and {SnW } Lindqvist-type hexametalates, a series of alkoxido- and aryloxido-tin substituted POMs (nBu N) [(RO)SnW O ] (R=Me, Et, iPr and tBu) and (nBu N) [(ArO)SnW O ] (Ar=C H , 4-MeC H , 4-tBuC H , 4-HOC H , 3-HOC H and 2-CHOC H ) has been structurally characterised and studied by multinuclear NMR ( H, C, O, Sn and W) and FTIR spectroscopy. Spectroscopic and structural parameters were compared with those of titanium-substituted homologues and, when coupled with theoretical studies, indicated that Sn-OR and Sn-OAr bonds are ionic with little π-contribution, whereas Ti-OR and Ti-OAr bonds are more covalent with π-bonding that is more prevalent for Ti-OR than Ti-OAr. This experimental and theoretical analysis of bonding in a homologous series of reactive POMs is the most extensive and detailed to date, and reveals factors which account for significant differences in reactivity between tin and titanium congeners.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Bonding Insights from Structural and Spectroscopic Comparisons of {SnW₅} and {TiW₅} Alkoxido‐ and Aryloxido‐Substituted Lindqvist Polyoxometalates

Kandasamy

Bruce

Clegg

et al. 2018

Chemistry A European J

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“…Intact {W 10 44 The spectrum of {Ta 2 W 8 } also yields a monolacunary fragment, [Ta 2 W 7 O 31 ] 10− . Intact {W 10 44 The spectrum of {Ta 2 W 8 } also yields a monolacunary fragment, [Ta 2 W 7 O 31 ] 10− .…”

Section: Esi-msmentioning

confidence: 99%

Bridging the opposite chemistries of tantalum and tungsten polyoxometalates

et al. 2015

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The disparate solubility, redox activity, and pH stability of the group V and group VI polyoxometalates (POMs) confer very different functionality on these species, and tailoring cluster properties by varying the ratio of group V to group VI metals poses both an opportunity and a synthetic challenge. A classic series of studies reported over 40 years ago provided some insight into W/Nb POMs, from which researchers have built on to date. However, the analogous W/Ta series has never been addressed in a systematic manner. Three members of this W/Ta series are presented here, synthesized from simple oxo- and peroxocoltanate precursors. [Ta3W3O19](5-) displays the Lindqvist-type structure, while [TaW9O32](5-) and [Ta2W8O32](6-) are isostructural with decatungstate ([W10O32](4-)). Additionally, the use of peroxoniobate instead of hexaniobate as the starting material drives the formation of the decatungstate-type structure [NbW9O32](5-) instead of the Lindqvist ion that was established to be the foundational cluster geometry in prior work. The electronic structure of the Nb/Ta substituted decatungstates is directly related to the degree of substitution inasmuch as the HOMO-LUMO energy gap (Egap) slightly increases as more Nb/Ta atoms are incorporated into the structure. The poor mixing of the d-orbitals of Nb/Ta and W is responsible for the observed trends in the UV spectra and cyclic voltammetry. Moreover, the stability of the molecular frameworks in the gas phase is also related to the extent of substitution as revealed by electrospray mass-spectrometry (ESI-MS).

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“…4). Peaks 50 at 717 and 248 ppm which were sometimes present in 17 O NMR spectra of hydrolysis products or of impure samples of (TBA) 3 2 (7) 24.9233 (5) 23.8573 (14) 24.049 (4) 16.1864(17) b /Å 18.6123 (7) 33.6182 (8) [5][6][7][8] and the presence of a TiOTi bridge between two TiMo 5 O 18 fragments in the structure of 7 ( Fig. 9).…”

Section: Introductionmentioning

confidence: 99%

Protonolysis of [(ⁱPrO)TiMo₅O₁₈]³⁻: access to a family of TiMo₅Lindqvist type polyoxometalates

et al. 2012

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The tetra-n-butylammonium (TBA) salts of [((i)PrO)TiMo(5)O(18)](3-) 1 and [((i)BuO)TiMo(5)O(18)](3-) 2 were prepared by hydrolysis of mixtures of (TBA)(2)[Mo(2)O(7)], (TBA)(4)α-[Mo(8)O(26)] and Ti(OR)(4) (R = (i)Pr or (i)Bu) in acetonitrile. Treatment of (TBA)(3)1 with alcohols ROH afforded primary and tertiary alkoxide derivatives [(RO)TiMo(5)O(18)](3-) (R = Me 3, (t)Bu 4), whilst aryloxides [(ArO)TiMo(5)O(18)](3-) were prepared by reacting 1 with phenols ArOH (Ar = C(6)H(4)Me-4 5, and C(6)H(4)CHO-2 6). Oxo-bridged [(μ-O)(TiMo(5)O(18))(2)](6-)7 rather than the hydroxo derivative [(HO)TiMo(5)O(18)](3-) was obtained upon hydrolysis of 1. X-Ray crystal structures of TBA salts of anions 3-7 show that titanium is six-coordinate in all cases, although titanium sites are disordered over two trans positions in 3. Mo-O bond length alternation is observed in the Mo(4)O(4) planes of 4 and 7 and in one of the two independent anions in the structure of 3. In solution, (17)O NMR spectra are consistent with the higher anionic charge compared to [Mo(6)O(19)](2-) and reveal an order of basicity for the anions [LM'Mo(5)O(18)](3-) associated with the ability of {LM'}(3+) to donate/withdraw electron density from {Mo(5)O(18)}(6-). Protonolysis reactions of 1 and 3 were slower than for tungstate analogues and the possibility of initial protonation at TiOM (M = Mo) rather than TiOR (M = W) in a proton-assisted S(N)1 mechanism for ligand exchange in [(RO)TiM(5)O(18)](3-) is discussed.

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Extending the Lindqvist Family to Late 3d Transition Metals: A Rational Entry to CoW₅ Hexametalate Chemistry

Cited by 28 publications

References 69 publications

Bonding Insights from Structural and Spectroscopic Comparisons of {SnW₅} and {TiW₅} Alkoxido‐ and Aryloxido‐Substituted Lindqvist Polyoxometalates

Bonding Insights from Structural and Spectroscopic Comparisons of {SnW₅} and {TiW₅} Alkoxido‐ and Aryloxido‐Substituted Lindqvist Polyoxometalates

Bridging the opposite chemistries of tantalum and tungsten polyoxometalates

Protonolysis of [(ⁱPrO)TiMo₅O₁₈]³⁻: access to a family of TiMo₅Lindqvist type polyoxometalates

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Extending the Lindqvist Family to Late 3d Transition Metals: A Rational Entry to CoW5 Hexametalate Chemistry

Cited by 28 publications

References 69 publications

Bonding Insights from Structural and Spectroscopic Comparisons of {SnW5} and {TiW5} Alkoxido‐ and Aryloxido‐Substituted Lindqvist Polyoxometalates

Bonding Insights from Structural and Spectroscopic Comparisons of {SnW5} and {TiW5} Alkoxido‐ and Aryloxido‐Substituted Lindqvist Polyoxometalates

Bridging the opposite chemistries of tantalum and tungsten polyoxometalates

Protonolysis of [(iPrO)TiMo5O18]3−: access to a family of TiMo5Lindqvist type polyoxometalates

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Extending the Lindqvist Family to Late 3d Transition Metals: A Rational Entry to CoW₅ Hexametalate Chemistry

Bonding Insights from Structural and Spectroscopic Comparisons of {SnW₅} and {TiW₅} Alkoxido‐ and Aryloxido‐Substituted Lindqvist Polyoxometalates

Bonding Insights from Structural and Spectroscopic Comparisons of {SnW₅} and {TiW₅} Alkoxido‐ and Aryloxido‐Substituted Lindqvist Polyoxometalates

Protonolysis of [(ⁱPrO)TiMo₅O₁₈]³⁻: access to a family of TiMo₅Lindqvist type polyoxometalates