Zur Hydrolyse amphoterer Metallalkoxide, X. Die Verseifung des Orthovanadinsäure‐tert.‐butylesters in Gegenwart von Tetraalkylammoniumbasen

Many synthetic methods for heteropolyoxovanadates and lacunary polyoxovanadates have been developed in recent years. We outline various approaches used to produce new polyoxovanadate species, including heterometal-incorporated complexes of tetravanadates, hexavanadates, decavanadates and dodecavanadates. In particular, three types of synthetic routes are explored; based on i) coordination of metavanadate species to transition metal cations, ii) oxidation of reduced polyoxovanadates, and iii) template synthesis. Metavanadate species can coordinate to metal cations as inorganic macrocyclic ligands to form heteropolyoxovanadates. The incorporation of a heterometal cation into decavanadates has also been reported. The oxidation reaction of reduced polyoxovanadates provides a new route to the formation of the lacunary polyoxovanadates, which can serve as inorganic host molecules. Dodecavanadates are bowl-type molecules of particular structural interest; a chloride anion can be incorporated into the bowl through a template synthesis. Structural transformations between these dodecavanadate species and alkoxopolyoxovanadates are also described.

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“…The synthesis of (n-Bu 4 N) 3 [H 3 V 10 O 28 ] has been carried out in this way [37]. To interaction.…”

Section: General Methods For the Synthesis Of Polyoxovanadatesmentioning

confidence: 99%

Hetero and lacunary polyoxovanadate chemistry: Synthesis, reactivity and structural aspects

Hayashi

2011

Coordination Chemistry Reviews

210

126

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“…However, the anionic nature of the described substituted classical POMs limits both the solubility and reactivity in organic media. Therefore, these polyanionic compounds were synthesized with large organic counterions, namely tetraalkylammonium cations, to introduce at least some solubility in polar organic solvents . Another disadvantage is the dependency of the self‐assembly of many structures on several influences like the pH value or the temperature.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3] Since this class of compounds exhibits av ast structural diversity,t ransition-metal oxide clusters of precisely defined size, shape, and composition can be tailor-made to serve a specific purpose.T heir propertiesd epend mainly on the structure and compositiono ft he metal-oxygen framework, butc an be tuned and extended by organic functionalization. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] An established functionalizationm ethod is to use derivatives of the tripodala lcohol tris(hydroxymethyl)methane with the formula (HOCH 2 ) 3 CÀR( "H 3 trisÀR'')t oi ntroduce organic moieties (R) to the POMs. [19] Lindqvist-, Dawson-, or Anderson-type structuresa re the most prominente xamples in which this functionalization strategyh as successfully been employed.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, these polyanionic compounds were synthesized with large organic counterions,n amely tetraalkylammonium cations,t oi ntroduce at least some solubility in polar organic solvents. [6,7] Another disadvantage is the dependency of the self-assembly of many structures on several influences like the pH value or the temperature. Many structures can coexist in solution in dynamic equilibria.…”

Section: Introductionmentioning

confidence: 99%

“…Since this class of compounds exhibits a vast structural diversity, transition‐metal oxide clusters of precisely defined size, shape, and composition can be tailor‐made to serve a specific purpose. Their properties depend mainly on the structure and composition of the metal–oxygen framework, but can be tuned and extended by organic functionalization …”

Section: Introductionmentioning

confidence: 99%

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Versatile Organic Chemistry on Vanadium‐Based Multi‐Electron Reservoirs

Nachtigall

Spandl

2018

Chemistry A European J

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We report the synthesis, post-functionalization, and redox behavior of two organically functionalized aggregates, [V O (OMe) {(OCH ) C-CH N }] and [V O (OMe) {(OCH ) C-NH }]. All twelve μ -oxo groups on the edges of the Lindqvist-type {V O } core were replaced by alkoxo ligands. The absence of a negative charge and the closed organic shell make these neutral mixed-valence compounds very stable towards hydrolysis and well soluble in almost all common organic solvents. These are important advantages over classical POMs. By post-functionalization through copper(I)-catalyzed Huisgen cycloaddition or imine formation, various organic moieties could be introduced. Even a well-soluble trimer composed of three hexanuclear vanadium units connected through an aromatic triimino core was synthesized and studied. The diverse redox behavior, the versatile reactivity, the good stability, and the excellent solubility make our vanadium compounds highly interesting for applications as building blocks in macromolecular chemistry as well as redox labels in biochemistry.

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Zur Hydrolyse amphoterer Metallalkoxide, XI. Die Verseifung des Tantal(V)‐säure‐pentaäthylesters in Gegenwart von Basen

1968

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Durch vorsichtige Hydrolyse von Tantal(V)-siure-pentaathylester in Gegenwart von Kaliumhydroxid, Piperidin oder Ammoniak erhalt man die definierten Polytantalate KsH~Ta12037, (C5HloNH2)sH9Ta12037 und (NH4)8HlzTa,8055. Aus letzterem entsteht beim 'T'rocknen in1 Vakuum (NH4)7H13Ta180SS. Die Umsetzung eines Hydrolyseproduktes des Esters mit eincr starken wal3rigen Piperidinlosung fuhrt zur Verbindung (CsHloNH2)hHsTal2037.Fiinfwertiges Tantal bildet in stark alkalischer, waiDriger Losung lsopolyanionen, in nicht zu verdunnten Mineralsauren auch Polykationen3). Kristallisierte Tantalsalze sind aus saurer Losung kaum zu erhalten, wohl aber kennt man einige kristallisierte Alkali-, Erdalkali-und Schwermetalltantalate4-~) (Tab.). Eine Rontgenstrukturanalyse wurde lediglich bei dem bereits von Marignar 71 beschriebenen Salz 4 K2O-3Ta2O~. l6H2O von Lindquizt und AronssonXJ durchgefuhrt. Aufgrund der Tantallagen ist das Salz als Hexatantalat, KBTa6019. 16H20, zu formulieren. Die Lage der Kalium-lonen und der Wassermolekiile im Gitter wurde nicht festgestellt.Uber den Losungszustand des funfwertigen Tantals gibt es bisher nur wenige Angaben. Mit Diffusions-und Lichtabsorptionsmessungen konnten Jandev und Ertelg) zeigen, darj in waiRrigen Kaliumhydroxidlosungen verschiedener Konzentration stels nur ein und dasselbe Tantalat-Ion auftritt. Nach Meinung der Autoren handelt es sich hierbei um das pentamere Ta50167 -. Nelson und Tobias 10' untersuchten w:iiBrige alkalische Kaliumtantalatlosungen im pH-Bereich 10 -13 mit der Ultrazentrifuge und nach anderen physikalischen Methoden und fanden auch nur ein einziges Tantalat-Ion, das sie jedoch als hexamer, HTa60197-, formulieren.

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Zur Hydrolyse amphoterer Metallalkoxide, X. Die Verseifung des Orthovanadinsäure‐tert.‐butylesters in Gegenwart von Tetraalkylammoniumbasen

Cited by 18 publications

References 11 publications

Hetero and lacunary polyoxovanadate chemistry: Synthesis, reactivity and structural aspects

Hetero and lacunary polyoxovanadate chemistry: Synthesis, reactivity and structural aspects

Versatile Organic Chemistry on Vanadium‐Based Multi‐Electron Reservoirs

Zur Hydrolyse amphoterer Metallalkoxide, XI. Die Verseifung des Tantal(V)‐säure‐pentaäthylesters in Gegenwart von Basen

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