Topic
Hemilability
About: Hemilability is a research topic. Over the lifetime, 167 publications have been published within this topic receiving 5755 citations.
Papers published on a yearly basis
Papers
TL;DR: The definition and scope of hemilabile ligands are recalled, the main classes of ligands containing one or more oxazoline moieties are presented, with an emphasis on hybrid ligands, and why the combination of these two facets of ligand design appears particularly promising are explained.
Abstract: Ligand design is becoming an increasingly important part of the synthetic activity in chemistry. This is of course because of the subtle control that ligands exert on the metal center to which they are coordinated. Ligands which contain significantly different chemical functionalities, such as hard and soft donors, are often called hybrid ligands and find increasing use in molecular chemistry. Although the interplay between electronic and steric properties has long been recognized as essential in determining the chemical or physical properties of a complex, predictions remain very difficult, not only because of the considerable diversity encountered within the Periodic Table-different metal centers will behave differently towards the same ligand and different ligands can completely modify the chemistry of a given metal-but also because of the small energy differences involved. New systems may-even through serendipity-allow the emergence of useful concepts that can gain general acceptance and help design molecular structures orientated towards a given property. The concept of ligand hemilability, which finds numerous illustrations with hybrid ligands, has gained increased acceptance and been found to be very useful in explaining the properties of metal complexes and in designing new systems for molecular activation, homogeneous catalysis, functional materials, or small-molecule sensing. In the field of homogeneous enantioselective catalysis, in which steric and/or electronic control of a metal-mediated process must occur in such a way that one stereoisomer is preferentially formed, ligands containing one or more chiral oxazoline units have been found to be very valuable for a wide range of metal-catalyzed reactions. The incorporation of oxazoline moieties in multifunctional ligands of increasing complexity makes such ligands good candidates to display hemilabile properties, which until recently, had not been documented in oxazoline chemistry. Herein, we briefly recall the definition and scope of hemilabile ligands, present the main classes of ligands containing one or more oxazoline moieties, with an emphasis on hybrid ligands, and finally explain why the combination of these two facets of ligand design appears particularly promising.
912 citations
TL;DR: In this article, the authors classify O,P ligands: ether-phosphines and furylphosphine, β-ketophosphines, δ-ketophosphine and β-carboxylates, αphosphinosulphoxides and their complexes.
777 citations
TL;DR: A comprehensive overview of the current state-of-the-art in first-row transition metal cooperative catalysts can be found in this article. But the focus of this paper is on the metal-ligand bifunctional substrate activation.
Abstract: Cooperative catalysis with first-row transition metals holds much promise for future developments regarding sustainable, selective transformations, including e.g. alkenes, dienes and a variety of small molecules such as CO2, N2 and water. This non-exhaustive analysis of the current state-of-the-art aims to give a comprehensive overview of the various design strategies and applications of first-row transition metal cooperative reactivity and to provide leads for new research initiatives in order to expand this emerging field. The main aspects covered involve bimetallic cooperativity, redox-noninnocent ligands in combination with first-row transition metal complexes, otherwise reactive or noninnocent scaffolds that can induce metal-ligand bifunctional substrate activation and the design of adaptive ligands and complexes thereof, wherein hemilability is a key factor for selective reactivity. The metals under review are primarily the late transition metals Fe, Co, Ni and Cu.
427 citations
TL;DR: A mechanism is proposed involving metal-ligand cooperation via aromatization-dearomatization of the pyridine moiety and hemilability of the amine arm ofThe pincer ligand, achieving efficient synthesis of amides directly from esters and amines with the liberation of molecular hydrogen.
Abstract: Efficient synthesis of amides directly from esters and amines is achieved under mild, neutral conditions with the liberation of molecular hydrogen. Both primary and secondary amines can be utilized. This unprecedented, general, environmentally benign reaction is homogeneously catalyzed under neutral conditions by a dearomatized ruthenium−pincer PNN complex and proceeds in toluene under an inert atmosphere with a high turnover number (up to 1000). PNP analogues do not catalyze this transformation, underlining the crucial importance of the amine arm of the pincer ligand. A mechanism is proposed involving metal−ligand cooperation via aromatization−dearomatization of the pyridine moiety and hemilability of the amine arm.
259 citations
TL;DR: The characterization of active Suzuki catalysts, which support sp(2)-sp(2) couplings, give valuable insights into the key Suzuki intermediates such as those arising from the reductive elimination, transmetallation, and oxidative addition steps.
Abstract: The combinative and complementary use of a hemilabile difunctional ligand on a metal, notably palladium, that is coordinatively and electronically unsaturated has led to the isolation of a string of unexpected low-valent complexes that are structurally intriguing. The ligands of interest are primarily ferrocenes functionalized by [P,N] and [P,O] donors. The characterization of these active Suzuki catalysts, which support sp2–sp2 couplings, give valuable insights into the key Suzuki intermediates such as those arising from the reductive elimination, transmetallation, and oxidative addition steps. In this Account, we shall review and discuss our recent results in relation to selected developments in other laboratories.
191 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 16 |
| 2020 | 15 |
| 2019 | 6 |
| 2018 | 10 |
| 2017 | 14 |
| 2016 | 6 |