Journal article
Metal-Ligand Cooperation by Aromatization-Dearomatization: A New Paradigm in Bond Activation and "Green" Catalysis
Accounts of Chemical Research, Vol.44(8), pp.588-602
Aug/2011
Abstract
In view of global concerns regarding the environment and sustainable energy resources, there is a strong need for the discovery of new, green catalytic reactions. For this purpose, fresh approaches to catalytic design are desirable. In recent years, complexes based on "cooperating" ligands have exhibited remarkable catalytic activity. These ligands cooperate with the metal center by undergoing reversible structural changes in the processes of substrate activation and product formation. We have discovered a new mode of metal-ligand cooperation, involving aromatization-dearomatization of ligands. Pincer-type ligands based on pyridine or acridine exhibit such cooperation, leading to unusual bond activation processes and to novel, environmentally benign catalysis. Bond activation takes place with no formal change in the metal oxidation state, and so far the activation of H-H, C-H (sp(2) and sp(3)), O-H, and N-H bonds has been demonstrated. Using this approach, we have demonstrated a unique water splitting process, which involves consecutive thermal liberation of H(2) and light-induced liberation of O(2), using no sacrificial reagents, promoted by a pyridine-based pincer ruthenium complex. An acridine pincer complex displays unique "long-range" metal-ligand cooperation in the activation of H(2) and in reaction with ammonia. In this Account, we begin by providing an overview of the metal-ligand cooperation based on aromatization-dearomatization processes. We then describe a range of novel catalytic reactions that we developed guided by these new modes of metal-ligand cooperation. These reactions include the following: (1) acceptorless dehydrogenation of secondary alcohols to ketones, (2) acceptorless dehydrogenative coupling of alcohols to esters, (3) acylation of secondary alcohols by esters with dihydrogen liberation, (4) direct coupling of alcohols and amines to form amides and polyamides with liberation of dihydrogen, (5) coupling of esters and amines to form amide
Details
- Title
- Metal-Ligand Cooperation by Aromatization-Dearomatization; A New Paradigm in Bond Activation and "Green" Catalysis
- Creators
- Chidambaram Gunanathan (null)David Milstein (null) - The Weizmann Institute of Science
- Resource Type
- Journal article; Review
- Publication Details
- Accounts of Chemical Research, Vol.44(8), pp.588-602; Aug/2011
- Number of pages
- 15
- Language
- English
- DOI
- https://doi.org/10.1021/ar2000265
- Grant note
- We thank all our co-workers, whose names appear in the cited references, for their valuable contributions. This research was supported by the European Research Council under the FP7 framework (ERC No 246837), by the Israel Science Foundation, by the MINERVA Foundation, by the DIP Program for German-Israeli Cooperation, by the Kimmel Center for Molecular Design, and by the Peter J. Cohn Fund. D.M. is the holder of the Israel Matz Professorial Chair._ALMAME_DELIMITER_
- Record Identifier
- 993265048003596
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