Compelling mechanistic data and identification of the active species in tungsten-catalyzed alkyne polymerizations: conversion of a trianionic pincer into a new tetraanionic pincer-type ligand

McGowan, Kevin P.; O’Reilly, Matthew E.; Ghiviriga, Ion; Abboud, Khalil A.; Veige, Adam S.

doi:10.1039/c2sc21750c

Cited by 59 publications

(101 citation statements)

References 105 publications

(150 reference statements)

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“…Both dimers are chemically equivalent but crystallographically independent. All the bond distances between the independent dimers vary by 0.0125(25) Å or less; for example, the Fe1−O1 and Fe1−O2 average bond 11.3214(5) 31.479 (2) 12.2812 (8) 13.5244 (6) 11.3312(3) b (Å) 18.4917 (8) 12.6762 (10) 13.3854 (9) 15.9041 (7) 11.9100(3) c (Å) 11.9749 (5) 27.582 (2) 18.4188 (13) 14.1139 (6) . Treating 4 with 0.5 equiv of 2,2′-bipyridine in DME results in a subtle color change from green to bluish green.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Synthesis, Characterization, and Reactivity of Iron(III) Complexes Supported by a Trianionic ONO^3– Pincer Ligand

Pascualini¹,

Russo²,

Quintero³

et al. 2014

Inorg. Chem.

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Synthetic and characterization results of a new family of Fe(III) compounds stabilized by a trianionic [CF3-ONO](3-) pincer-type ligand are reported. The ligand possesses three negatively charged donors constrained to the meridional positions that provide sufficient electron density to stabilize high-valent metal complexes. Using the redox-insulated [CF3-ONO](3-), pentacoordinated square-pyramidal {[CF3-ONO]FeCl2}{LiTHF2}2 (3), dimeric μ-DME{[CF3-ONO]FeDME}2 (4), trigonal bipyramidal [CF3-ONO]Fe(bpy) (5), and octahedral [CF3-ONO]Fe(bpy)H2O (5·H2O) complexes are synthesized. An interesting feature of the [CF3-ONO](3-) pincer-type ligand is its ability to coordinate the metal center in both the more common meridional positions or occupying a face of a trigonal bipyramidal complex. The molecular structure of 3 contains structural features similar to those of a rare square-planar high-spin Fe(II) complex, and the important role of the counterions in stabilizing a square-plane is emphasized. SQUID magnetometry measurements of 3 reveal its high-spin character, and cyclic voltammetry measurements indicate high oxidation state species are unstable. However, all compounds can be reduced, and in particular 5 displays a reversible reduction event at -2255 mV versus ferrocene (Fc(+)/Fc) that can be assigned to either the Fe(I)/Fe(0) couple or 2,2'-bipyridine reduction.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Synthesis, Characterization, and Reactivity of Iron(III) Complexes Supported by a Trianionic ONO^3– Pincer Ligand

Pascualini¹,

Russo²,

Quintero³

et al. 2014

Inorg. Chem.

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“…Following on the heels of this discovery, Veige and Wagener et al recently reported the first example of cyclic polymers made via REMP of alkyne monomers . An enabling advance was the improved synthesis of the tethered tungsten catalyst shown in Figure , which is obtained in quantitative, isolable yields by treatment of the tungsten alkylidyne precatalyst with excess 3,3‐dimethyl‐1‐butyne rather than phenylacetylene as previously reported . Upon dissociation of THF, the catalyst is activated and can coordinate an alkyne to generate the metallacyclopentadiene B (Fig.…”

Section: Ring‐expansion Polymerizationmentioning

confidence: 99%

Recent progress on the synthesis of cyclic polymers via ring‐expansion strategies

Chang

Waymouth

2017

J. Polym. Sci. Part A: Polym. Chem.

124

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Cyclic polymers are the simplest topological isomers of linear macromolecules, but exhibit properties that differ from linear chains in ways that remain imperfectly understood. The difficulty of synthesizing appropriately pure and high molecular weight cyclic samples has hindered experimental studies. Ringclosure methods, while versatile, are inherently limited in the range of molecular weights that can be achieved. Ringexpansion methods are a much more promising strategy toward obtaining high molecular weight cyclic polymers. The current review focuses on recent developments in ring-expansion polymerization strategies toward the synthesis of high molecular weight cyclic polymers. Significant progress in the last decade has made the synthesis of cyclic polymers possible by a variety of methods, such as ruthenium-and tungsten-catalyzed ringexpansion metathesis polymerization, organocatalytic and Lewis acid-catalyzed zwitterionic polymerization, RAFT and nitroxidemediated radical polymerization, among many others. While the study of cyclic polymers has long been hampered by synthetic challenges, the recent resurgence of interest in this field presents an exciting opportunity for chemists. V C 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 2892-2902 KEYWORDS: cationic polymerization; cyclic polymers; cyclopolymerization; Grubbs catalyst; macrocycles; macrocyclic polymerization; metathesis polymerization; ring-expansion polymerization; zwitterionic polymerization INTRODUCTION Most of our knowledge of the physical and dynamic properties of polymers derives from investigations of linear chain macromolecules. Cyclic polymers, topological isomers of linear chains, differ from their linear congeners by only one bond, and yet this topological difference leads to behavior that, in many respects, remains poorly understood. Early heroic synthetic efforts to generate and investigate high molecular weight cyclic macromolecules 1-4 were compromised by the dramatic influence of even minor amounts of linear contaminants on the properties (esp. rheological properties) of cyclic chains. 1,[5][6][7] The synthesis of cyclic macromolecules of sufficient quantity and purity has proven to be a formidable challenge and has imposed a significant limitation on the study of their behavior as a function of molecular weight. Until recently, only a limited number of different classes of cyclic polymers have been prepared and investigated. Nevertheless, these pioneering studies have shown that cyclic polymers behave in a way that can be quite different from their linear counterparts despite their nearidentical chemical compositions. Cyclic polymers, for instance, cannot reptate or entangle 3,5,7,8 in the same way that linear polymers do and have a smaller radius of gyration in solution, leading to lower solution viscosities. 1,6

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“…Als Metalle können Cr, Mo, W, Ti, Zr, Ta, Sm und Yb genutzt werden. Erfolgreiche Anwendungen der meta ‐Terphenyl‐2,2′′‐diole als Pincerliganden wurde bereits für Sauerstoff‐ und Stickstoffübertragungsreaktionen, Polymerisation von Acetylenen und Olefinen, Alkenisomerisation, Nitren‐ und Carbengruppenübertragungen, O 2 ‐ und C‐H‐Aktivierung, Disulfidreduktionen und aerobe Oxidationen nachgewiesen. Sie können ebenfalls für die Synthese von Kronenethern, modernen Gassensoren, molekularen Schaltern und Photosensibilisatoren genutzt werden.…”

Section: Methodsunclassified

Synthese von meta‐Terphenyl‐2,2′′‐diolen durch anodische C‐C‐Kreuzkupplungen

et al. 2016

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Die anodische C‐C‐Kreuzkupplung ist eine vielseitig einsetzbare Transformation, die eine gezielte Synthese von Biphenolen und arylierten Phenolen ermöglicht. Wir berichten über einen ebenfalls elektrosynthetischen, metallfreien Ansatz, der einen Zugang zu symmetrischen und nichtsymmetrischen meta‐Terphenyl‐2,2′′‐diolen in guten Ausbeuten und hoher Selektivität ermöglicht. Symmetrische Derivate können durch eine direkte Synthese in einer ungeteilten Zelle gewonnen werden, wohingegen nichtsymmetrische meta‐Terphenyl‐2,2′′‐diole zwei elektrochemische Stufen benötigen. Die milde Methode ist einfach durchzuführen und skalierbar. Außerdem konnte erstmalig eine breite Substratvariabilität aufgezeigt werden, die eine Vielzahl funktioneller Gruppen toleriert. Die erhaltenen Strukturen könnten als [OCO]3−‐Pincerliganden genutzt werden.

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Compelling mechanistic data and identification of the active species in tungsten-catalyzed alkyne polymerizations: conversion of a trianionic pincer into a new tetraanionic pincer-type ligand

Cited by 59 publications

References 105 publications

Synthesis, Characterization, and Reactivity of Iron(III) Complexes Supported by a Trianionic ONO^3– Pincer Ligand

Synthesis, Characterization, and Reactivity of Iron(III) Complexes Supported by a Trianionic ONO^3– Pincer Ligand

Recent progress on the synthesis of cyclic polymers via ring‐expansion strategies

Synthese von meta‐Terphenyl‐2,2′′‐diolen durch anodische C‐C‐Kreuzkupplungen

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Compelling mechanistic data and identification of the active species in tungsten-catalyzed alkyne polymerizations: conversion of a trianionic pincer into a new tetraanionic pincer-type ligand

Cited by 59 publications

References 105 publications

Synthesis, Characterization, and Reactivity of Iron(III) Complexes Supported by a Trianionic ONO3– Pincer Ligand

Synthesis, Characterization, and Reactivity of Iron(III) Complexes Supported by a Trianionic ONO3– Pincer Ligand

Recent progress on the synthesis of cyclic polymers via ring‐expansion strategies

Synthese von meta‐Terphenyl‐2,2′′‐diolen durch anodische C‐C‐Kreuzkupplungen

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Product

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Synthesis, Characterization, and Reactivity of Iron(III) Complexes Supported by a Trianionic ONO^3– Pincer Ligand

Synthesis, Characterization, and Reactivity of Iron(III) Complexes Supported by a Trianionic ONO^3– Pincer Ligand