Antimony and Bismuth Complexes in Organic Synthesis

Chitnis, Saurabh S.; Hynes, Toren

doi:10.1016/b978-0-12-820206-7.00025-1

Cited by 3 publications

(1 citation statement)

References 234 publications

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“…In recent years, the organometallic chemistry of bismuth has re-emerged as a hot topic across multiple areas of synthetic chemistry and catalysis. − Bismuth is particularly appealing due to its nontoxic and environmentally benign nature, which may have future implications in the development of chemical transformations that do not rely on toxic or precious metals . Owing to high-lying, partially filled orbitals, low-valent bismuth compounds are well-positioned to mimic the synergistic effect of d -orbitals in challenging bond activation events. − Despite these positive attributes, isolating well-defined bismuth complexes can be synthetically challenging due to the ease at which many compounds undergo thermal decomposition to bismuth metal or the corresponding oxy-salts.…”

Section: Introductionmentioning

confidence: 99%

A Multidimensional Approach to Carbodiphosphorane–Bismuth Coordination Chemistry: Cationization, Redox-Flexibility, and Stabilization of a Crystalline Bismuth Hydridoborate

et al. 2022

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Bismuth complexes stabilized by carbon-based donor ligands are underserved by their instability, often due to facile ligand dissociation and deleterious protonolysis. Herein, we show that the ortho-bismuthination of hexaphenylcarbodiphosphorane enables a robust framework with geometrically constrained carbone–bismuth bonding interactions, which are highly tunable by cationization. The carbodiphosphorane bismuth halides (1 and 2) are remarkably air-stable and feature unprecedented trans carboneC–Bi–X ligation, resulting in highly elongated Bi–X bonds. In contrast to known carbone–bismuth complexes, hydrolytic activation of the carbone yields well-defined organobismuth complexes, and subsequent dehydrohalogenation is feasible using potassium bis(trimethylsilyl)amide or N-heterocyclic carbenes. The redox-flexibility of this framework was evaluated in the high catalytic activity of 1 and 2 for silylation of 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) under mild conditions (50 °C, 24–96 h) and low catalyst loadings (5–10 mol %), which suggests the accessibility of short-lived hydridic and radical bismuth species. The reaction of 1, PhSiH3, and tris(pentafluorophenyl)borane (BCF) yields the first crystallographically characterized bismuth hydridoborate complex as an ionic species (9), presumably by BCF-mediated hydride abstraction from an unobserved [Bi]–H intermediate. All isolated compounds have been characterized by heteronuclear NMR spectroscopy and X-ray crystallography, and the bonding situation in representative complexes (1, 2, 5, and 9) were further evaluated using density functional theory.

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Section: Introductionmentioning

confidence: 99%

A Multidimensional Approach to Carbodiphosphorane–Bismuth Coordination Chemistry: Cationization, Redox-Flexibility, and Stabilization of a Crystalline Bismuth Hydridoborate

et al. 2022

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1,3‐Imidazol‐basierte mesoionische Carbene und anionische Dicarbene: Erweiterung der Grenzen klassischer N‐heterocyclischer Carbene

Ghadwal

2023

Angewandte Chemie

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Klassische N‐heterocyclische Carbene (NHCs) mit dem Carbenzentrum an der C2‐Position des 1,3‐Imidazolgerüsts (d.h. C2‐Carbene) sind als vielseitige neutrale Liganden sowohl in der Molekularforschung als auch in den Materialwissenschaften bekannt. Die Effizienz und der Erfolg der NHCs in verschiedenen Bereichen ist im Wesentlichen auf ihre überzeugenden stereoelektronischen Eigenschaften zurückzuführen, insbesondere auf die starke σ‐Donoreigenschaft. Die NHCs mit dem Carbenzentrum an der ungewöhnlichen C4‐ (oder C5‐) Position, die sogenannten abnormalen NHCs (aNHCs) oder mesoionischen Carbene (iMICs), sind jedoch deutlich stärkere σ‐Donatoren als C2‐Carbene. Deshalb haben iMICs ein erhebliches Potenzial als Liganden in der nachhaltigen Synthese und Katalyse. Das Haupthindernis auf diesem Weg ist die anspruchsvolle synthetische Zugänglichkeit zu iMICs. Das Ziel dieses Übersichtsartikels ist es, die aktuellen Fortschritte, insbesondere der Forschungsgruppe des Autors, im Hinblick auf den Zugang zu stabilen iMICs, die Quantifizierung ihrer Eigenschaften sowie die Erforschung ihrer Anwendungen in Synthese und Katalyse aufzuzeigen. Darüber hinaus werden die synthetische Eignung und die Verwendung vicinaler C4,C5‐anionische Dicarbene (ADCs), die ebenfalls auf einem 1,3‐Imidazolgerüst basieren, vorgestellt. Wie auf den folgenden Seiten deutlich wird, haben iMICs und ADCs das Potenzial, die Grenzen der klassischen NHCs zu erweitern, indem sie den Zugang zu konzeptionell neuartigen Hauptgruppenelement‐Heterocyclen, Radikalen, molekularen Katalysatoren, Ligandensätzen und mehr ermöglichen.

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1,3‐Imidazole‐Based Mesoionic Carbenes and Anionic Dicarbenes: Pushing the Limit of Classical N‐Heterocyclic Carbenes

Ghadwal

2023

Angew Chem Int Ed

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Classical N‐heterocyclic carbenes (NHCs) featuring the carbene center at the C2‐position of 1,3‐imidazole framework (i.e. C2‐carbenes) are well acknowledged as very versatile neutral ligands in molecular as well as in materials sciences. The efficiency and success of NHCs in diverse areas is essentially attributed to their persuasive stereoelectronics, in particular the potent σ‐donor property. The NHCs with the carbene center at the unusual C4 (or C5) position, the so‐called abnormal NHCs (aNHCs) or mesoionic carbenes (iMICs), are however superior σ‐donors than C2‐carbenes. Hence, iMICs have substantial potential in sustainable synthesis and catalysis. The main obstacle in this direction is rather demanding synthetic accessibility of iMICs. The aim of this review article is to highlight recent advances, particularly by the author's research group, in accessing stable iMICs, quantifying their properties, and exploring their applications in synthesis and catalysis. In addition, the synthetic viability and use of vicinal C4,C5‐anionic dicarbenes (ADCs), also based on an 1,3‐imidazole framework, are presented. As will be apparent on following pages, iMICs and ADCs hold potentials in pushing the limit of classical NHCs by enabling access to conceptually new main‐group heterocycles, radicals, molecular catalysts, ligands sets, and more.

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Antimony and Bismuth Complexes in Organic Synthesis

Cited by 3 publications

References 234 publications

A Multidimensional Approach to Carbodiphosphorane–Bismuth Coordination Chemistry: Cationization, Redox-Flexibility, and Stabilization of a Crystalline Bismuth Hydridoborate

A Multidimensional Approach to Carbodiphosphorane–Bismuth Coordination Chemistry: Cationization, Redox-Flexibility, and Stabilization of a Crystalline Bismuth Hydridoborate

1,3‐Imidazol‐basierte mesoionische Carbene und anionische Dicarbene: Erweiterung der Grenzen klassischer N‐heterocyclischer Carbene

1,3‐Imidazole‐Based Mesoionic Carbenes and Anionic Dicarbenes: Pushing the Limit of Classical N‐Heterocyclic Carbenes

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