Emergence of a New [NNN] Pincer Ligand via Si−H Bond Activation and β‐Hydride Abstraction at Tetravalent Cerium
The cerium(IV) pyrazolate complexes [Ce(Me2pz)4]2 and [Ce(Me2pz)4(thf)] initiate β‐hydride ion of the bis(dimethylsilyl)amido moiety, to afford a heteroleptic cerium(IV) species containing a dimethylpyrazolyl‐substituted silylamido ligand, namely [Ce(Me2pz)3(bpsa)] (bpsa=bis((3,5‐dimethylpyrazol‐1‐y...
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Published in | Chemistry : a European journal Vol. 26; no. 53; pp. 12194 - 12205 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Weinheim
Wiley Subscription Services, Inc
21.09.2020
John Wiley and Sons Inc |
Subjects | |
Online Access | Get full text |
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Summary: | The cerium(IV) pyrazolate complexes [Ce(Me2pz)4]2 and [Ce(Me2pz)4(thf)] initiate β‐hydride ion of the bis(dimethylsilyl)amido moiety, to afford a heteroleptic cerium(IV) species containing a dimethylpyrazolyl‐substituted silylamido ligand, namely [Ce(Me2pz)3(bpsa)] (bpsa=bis((3,5‐dimethylpyrazol‐1‐yl)dimethylsilyl)amido; Me2pz =3,5‐dimethylpyrazolato), along with some cerium(III) species. Remarkably, the nucleophilic attack of the pyrazolyl at the silicon atom and concomitant Si−H‐bond cleavage is restricted to the tetravalent cerium oxidation state and appears to proceed via the formation of a transient cerium(IV) hydride, which engages in immediate redox chemistry. When [Ce(Me2pz)4]2 is treated with [Li{N(SiMe3)2}], that is, in the absence of the SiH functionality, any redox chemistry did not occur. Instead, the ceric ate complex [LiCe2(Me2pz)9] and the stable mixed‐ligand ceric species [Ce(Me2pz)2{N(SiMe3)2}2] were obtained.
Putative heteroleptic ceric species [Ce(Me2pz)x{N(SiHMe2)2}4−x] promote the formation of a new monoanionic dipyrazolylamido pincer ligand, while both tetravalent [Ce(Me2pz)2{N(SiMe3)2}2] and trivalent [Li2(thf)2Ce(Me2pz)2{N(SiHMe2)2}3] are isolable and stable. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0947-6539 1521-3765 |
DOI: | 10.1002/chem.202000625 |