Trimethylammonium[tetrakis(pentafluorophenoxy)borate], a safe way to synthesize novel co-catalysts for olefin polymerization

Kaul, Franz A.R.; Puchta, Gerd T.; Schneider, Horst; Grosche, Manja; Mihalios, Dimitrios; Herrmann, Wolfgang A.

doi:10.1016/s0022-328x(00)00861-5

Cited by 15 publications

(19 citation statements)

References 10 publications

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“…Oxophilic and strongly Lewis acidic atoms M, such as B III , Al III , Nb V , Ta V , Y III , and La III were used as center of the “ate” complexes [M(OR F ) n ] − 47–51 and [M(OAr F ) n ] − 52. 53 Compared to the [B(C 6 F 5 ) 4 ] − ion and related borates these metallates offer the advantage of being easily and safely accessible on a lagre scale. Their preparation circumvents the need to make LiC 6 F 5 , which is required in the generation of [B(C 6 F 5 ) 4 ] − , related borates, as well as B(C 6 F 5 ) 3 , and which is known to be unstable towards LiF elimination; its use has led to several explosions.…”

Section: The Candidatesmentioning

confidence: 99%

“…The [M(OC 6 F 5 ) n ] − ions generate cationic polymerization catalysts which have activities that are similar to, or even higher than those of catalysts partnered with the [B(C 6 F 5 ) 4 ] − ion 52. 53 However, the fluorinated aryloxide‐based [M(OC 6 F 5 ) 6 ] − ions with M=Nb or Ta are susceptible to OC 6 F 5 abstraction by sterically open cationic zirconocene catalysts, such as [Cp 2 ZrMe] + (Cp=C 5 H 5 ) 52. In addition, the oxygen atoms and the CF bonds of the OAr F ligands in [M(OAr F ) n ] − 52 have a tendency to coordinate.…”

Section: The Candidatesmentioning

confidence: 99%

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Noncoordinating Anions—Fact or Fiction? A Survey of Likely Candidates

2004

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Is there anything resembling a truly noncoordinating anion? Would it not be great to be able to prepare any crazy, beautiful, or simply useful cationic species that one has in mind, or has detected by mass spectroscopy? In condensed phases the target cation has to be partnered with a suitable counteranion. This is the moment when difficulties arise and many wonderful ideas end in the sink owing to coordination or decomposition of the anion. However, maybe these counteranion problems can be overcome by one of the new weakly coordinating anions (WCAs). Herein is an overview on the available candidates in the quest for the least coordinating anion and a summary of new applications, available starting materials, and general strategies to introduce a WCA into a system. Some of the unusual properties of WCA salts such as high solubility in low dielectric media, pseudo gas-phase conditions in condensed phases, and the stabilization of weakly bound and low-charged complexes are rationalized on thermodynamic grounds. Limits of the WCAs, that is, anion coordination and decomposition, are shown and a quantum chemical analysis of all types of WCAs is presented which allows the choice of a particular WCA to be based on quantitative data from a wide range of different anions.

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Section: The Candidatesmentioning

confidence: 99%

Section: The Candidatesmentioning

confidence: 99%

Noncoordinating Anions—Fact or Fiction? A Survey of Likely Candidates

2004

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“…Eine neue Alternative zu den in Abschnitt 2.1 beschriebenen fluorierten Tetraarylboraten sind poly‐ oder perfluorierte Alkoxy(OR F )‐ und Aryloxy(OAr F )‐Metallate (Abbildung 3). Oxophile und stark Lewis‐saure Metallatome wie B III , Al III , Nb V , Ta V , Y III und La III wurden als Zentren der at‐Komplexe [M(OR F ) n ] − 47–51 und [M(OAr F ) n ] − 52, 53 herangezogen. Gegenüber [B(C 6 F 5 ) 4 ] − und verwandten Boraten haben diese Metallate den großen Vorteil, dass sie präparativ einfach und gefahrlos zugänglich sind.…”

Section: Die Kandidatenunclassified

“…Es zeigte sich, dass die [M(OC 6 F 5 ) n ] − ‐Ionen sehr aktive kationische Polymerisationskatalysatoren generieren, die mindestens die gleichen Aktivitäten aufweisen wie Katalysatoren mit dem [B(C 6 F 5 ) 4 ] − ‐Gegenion 52. 53 Allerdings sind die [M(OC 6 F 5 ) 6 ] − ‐Ionen mit M=Nb und Ta empfindlich gegen OC 6 F 5 ‐Abstraktion durch sterisch schwach abgeschirmte kationische Zirconocen‐Katalysatoren wie [Cp 2 ZrMe] + 52. Außerdem neigen die Sauerstoffatome und die C‐F‐Bindungen der OAr F ‐Liganden in [M(OAr F ) n ] − zur Koordination 52.…”

Section: Die Kandidatenunclassified

Nichtkoordinierende Anionen – Traum oder Wirklichkeit? Eine Übersicht zu möglichen Kandidaten

2004

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Gibt es so etwas wie ein wirklich nichtkoordinierendes Anion? Wäre es nicht großartig, jede verrückte, schöne oder einfach nur nützliche kationische Spezies herstellen zu können, sei es, weil sie einen gerade interessiert oder weil man sie vielleicht schon einmal im Massenspektrum entdeckt hat? Um dieses Ziel in kondensierter Phase zu erreichen, müssen die Zielkationen mit einem geeigneten Gegenion versehen werden – dies ist der Moment, bei dem häufig Schwierigkeiten auftreten und viele gute Ideen wegen einer Koordination oder Zersetzung des Anions im Abguss enden. Zur Lösung des Problems bietet sich womöglich eines der neuen schwach koordinierenden Anionen (WCAs) an, die Gegenstand dieses Aufsatzes sind. Vorgestellt werden neue Entwicklungen, Anwendungen, Ausgangsmaterialien und allgemeine Strategien zur Einführung von WCAs in ein System. Einige der ungewöhnlichen Eigenschaften von WCA‐Salzen wie hohe Löslichkeit in unpolaren Medien, Pseudo‐Gasphasenbedingungen in der kondensierten Phase oder die Stabilisierung von schwach gebundenen und niedrig geladenen Komplexen werden anhand thermodynamischer Betrachtungen plausibel gemacht. Die Grenzen bei der Verwendung von WCAs – durch Koordination und Zersetzung – werden aufgezeigt, und eine quantenchemische Analyse der WCA‐Typen wird vorgestellt. Dies ermöglicht es, die Entscheidung für ein spezielles WCA auf der Basis von harten quantitativen Daten aus einer Vielzahl von Anionen zu gründen.

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“…Common protocols start with boron trichloride in the presence of an auxiliary base providing directly the anionic tetragonal derivative [18]. However, this approach can also lead to an unusual tautomeric form of the phenolate [19].…”

Section: Borate Template-directed Phenol Coupling Reactionsmentioning

confidence: 99%

Novel anodic concepts for the selective phenol coupling reaction

Waldvogel

2010

Pure and Applied Chemistry

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The oxidative phenol coupling reaction of phenols with simple methyl substituents can be difficult due to several by-products. Such a challenging substrate is 2,4-dimethylphenol. We studied the electrochemical access to the ortho-coupled dehydrodimer. Anodic treatment in a basic electrolyte supports the formation of a molecular tricyclic architecture called Pummerer's ketone. Employing a two-step sequence involving anodic conversion of 2,4-dimethylphenol to a preliminary substrate and different workup protocols yield exclusively and diastereoselectively polycyclic architectures. The selective ortho-coupling reaction was achieved by two strategies: A tetraphenoxy borate can be used as template substrate which can be easily made in large scale. Due to the ionic nature of the borate, no supporting electrolyte is required. This methodology can be applied to several related phenolic substrates. The second route is described by the direct conversion of 2,4-dimethylphenol on boron-doped diamond anodes. Surprisingly, the electrochemical transformation does not destruct or mineralize the substrate. Fluorinated additives allow the conversion of a broad scope of substrates.Scheme 5 Highly efficient synthesis of 2 on BDD anodes by partial conversion.Scheme 6 Synthesized biphenols on BDD anodes with 1,1,1,3,3,3-hexafluoroisopropanol as additive.

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Trimethylammonium[tetrakis(pentafluorophenoxy)borate], a safe way to synthesize novel co-catalysts for olefin polymerization

Cited by 15 publications

References 10 publications

Noncoordinating Anions—Fact or Fiction? A Survey of Likely Candidates

Noncoordinating Anions—Fact or Fiction? A Survey of Likely Candidates

Nichtkoordinierende Anionen – Traum oder Wirklichkeit? Eine Übersicht zu möglichen Kandidaten

Novel anodic concepts for the selective phenol coupling reaction

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