A Cobalt(I) Pincer Complex with an η2-Caryl-H Agostic Bond: Facile C-H Bond Cleavage through Deprotonation, Radical Abstraction, and Oxidative Addition

Sathiyamoorthy Murugesan; Berthold Stöger; Ernst Pittenauer; Günter Allmaier; Luis F. Veiros; Karl Kirchner

doi:10.1002/anie.201510145

A Cobalt(I) Pincer Complex with an η²-C_aryl-H Agostic Bond: Facile C-H Bond Cleavage through Deprotonation, Radical Abstraction, and Oxidative Addition

Sathiyamoorthy Murugesan, Berthold Stöger, Ernst Pittenauer, Günter Allmaier, Luis F. Veiros, Karl Kirchner

Research output: Contribution to journal › Article › peer-review

41 Scopus citations

Abstract

The synthesis and reactivity of a Co^I pincer complex [Co(°³P,CH,P-P(CH)P^NMe-iPr)(CO)₂]⁺ featuring an η²- C_aryl-H agostic bond is described. This complex was obtained by protonation of the Co^I complex [Co(PCP^NMe-iPr)(CO)₂]. The Co^III hydride complex [Co(PCP^NMe-iPr)(CNtBu)₂(H)]⁺ was obtained upon protonation of [Co(PCP^NMe-iPr)(CNtBu)₂]. Three ways to cleave the agostic C-H bond are presented. First, owing to the acidity of the agostic proton, treatment with pyridine results in facile deprotonation (C-H bond cleavage) and reformation of [Co(PCP^NMe-iPr)(CO)₂]. Second, C-H bond cleavage is achieved upon exposure of [Co(°³P,CH,P-P(CH)P^NMe-iPr)(CO)₂]⁺ to oxygen or TEMPO to yield the paramagnetic Co^II PCP complex [Co(PCP^NMe-iPr)(CO)₂]⁺. Finally, replacement of one CO ligand in [Co(°³P,CH,P-P(CH)P^NMe-iPr)(CO)₂]⁺ by CNtBu promotes the rapid oxidative addition of the agostic η²-C_aryl-H bond to give two isomeric hydride complexes of the type [Co(PCP^NMe-iPr)(CNtBu)(CO)(H)]⁺.

Original language	English
Pages (from-to)	3045-3048
Number of pages	4
Journal	Angewandte Chemie - International Edition
Volume	55
Issue number	9
DOIs	https://doi.org/10.1002/anie.201510145
State	Published - 24 Feb 2016
Externally published	Yes

Bibliographical note

Publisher Copyright:
© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Keywords

C-H activation
agostic interactions
cobalt
pincer complexes
protonation

ASJC Scopus subject areas

Catalysis
General Chemistry

Access to Document

10.1002/anie.201510145

Cite this

@article{c1a12230ed31430e87f66235cc31fa4d,

title = "A Cobalt(I) Pincer Complex with an η2-Caryl-H Agostic Bond: Facile C-H Bond Cleavage through Deprotonation, Radical Abstraction, and Oxidative Addition",

abstract = "The synthesis and reactivity of a CoI pincer complex [Co(°3P,CH,P-P(CH)PNMe-iPr)(CO)2]+ featuring an η2- Caryl-H agostic bond is described. This complex was obtained by protonation of the CoI complex [Co(PCPNMe-iPr)(CO)2]. The CoIII hydride complex [Co(PCPNMe-iPr)(CNtBu)2(H)]+ was obtained upon protonation of [Co(PCPNMe-iPr)(CNtBu)2]. Three ways to cleave the agostic C-H bond are presented. First, owing to the acidity of the agostic proton, treatment with pyridine results in facile deprotonation (C-H bond cleavage) and reformation of [Co(PCPNMe-iPr)(CO)2]. Second, C-H bond cleavage is achieved upon exposure of [Co(°3P,CH,P-P(CH)PNMe-iPr)(CO)2]+ to oxygen or TEMPO to yield the paramagnetic CoII PCP complex [Co(PCPNMe-iPr)(CO)2]+. Finally, replacement of one CO ligand in [Co(°3P,CH,P-P(CH)PNMe-iPr)(CO)2]+ by CNtBu promotes the rapid oxidative addition of the agostic η2-Caryl-H bond to give two isomeric hydride complexes of the type [Co(PCPNMe-iPr)(CNtBu)(CO)(H)]+.",

keywords = "C-H activation, agostic interactions, cobalt, pincer complexes, protonation",

author = "Sathiyamoorthy Murugesan and Berthold St{\"o}ger and Ernst Pittenauer and G{\"u}nter Allmaier and Veiros, \{Luis F.\} and Karl Kirchner",

note = "Publisher Copyright: {\textcopyright} 2016 WILEY-VCH Verlag GmbH \& Co. KGaA, Weinheim.",

year = "2016",

month = feb,

day = "24",

doi = "10.1002/anie.201510145",

language = "English",

volume = "55",

pages = "3045--3048",

journal = "Angewandte Chemie - International Edition",

issn = "1433-7851",

number = "9",

}

A Cobalt(I) Pincer Complex with an η²-C_aryl-H Agostic Bond: Facile C-H Bond Cleavage through Deprotonation, Radical Abstraction, and Oxidative Addition. / Murugesan, Sathiyamoorthy; Stöger, Berthold; Pittenauer, Ernst et al.
In: Angewandte Chemie - International Edition, Vol. 55, No. 9, 24.02.2016, p. 3045-3048.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - A Cobalt(I) Pincer Complex with an η2-Caryl-H Agostic Bond

T2 - Facile C-H Bond Cleavage through Deprotonation, Radical Abstraction, and Oxidative Addition

AU - Murugesan, Sathiyamoorthy

AU - Stöger, Berthold

AU - Pittenauer, Ernst

AU - Allmaier, Günter

AU - Veiros, Luis F.

AU - Kirchner, Karl

PY - 2016/2/24

Y1 - 2016/2/24

N2 - The synthesis and reactivity of a CoI pincer complex [Co(°3P,CH,P-P(CH)PNMe-iPr)(CO)2]+ featuring an η2- Caryl-H agostic bond is described. This complex was obtained by protonation of the CoI complex [Co(PCPNMe-iPr)(CO)2]. The CoIII hydride complex [Co(PCPNMe-iPr)(CNtBu)2(H)]+ was obtained upon protonation of [Co(PCPNMe-iPr)(CNtBu)2]. Three ways to cleave the agostic C-H bond are presented. First, owing to the acidity of the agostic proton, treatment with pyridine results in facile deprotonation (C-H bond cleavage) and reformation of [Co(PCPNMe-iPr)(CO)2]. Second, C-H bond cleavage is achieved upon exposure of [Co(°3P,CH,P-P(CH)PNMe-iPr)(CO)2]+ to oxygen or TEMPO to yield the paramagnetic CoII PCP complex [Co(PCPNMe-iPr)(CO)2]+. Finally, replacement of one CO ligand in [Co(°3P,CH,P-P(CH)PNMe-iPr)(CO)2]+ by CNtBu promotes the rapid oxidative addition of the agostic η2-Caryl-H bond to give two isomeric hydride complexes of the type [Co(PCPNMe-iPr)(CNtBu)(CO)(H)]+.

AB - The synthesis and reactivity of a CoI pincer complex [Co(°3P,CH,P-P(CH)PNMe-iPr)(CO)2]+ featuring an η2- Caryl-H agostic bond is described. This complex was obtained by protonation of the CoI complex [Co(PCPNMe-iPr)(CO)2]. The CoIII hydride complex [Co(PCPNMe-iPr)(CNtBu)2(H)]+ was obtained upon protonation of [Co(PCPNMe-iPr)(CNtBu)2]. Three ways to cleave the agostic C-H bond are presented. First, owing to the acidity of the agostic proton, treatment with pyridine results in facile deprotonation (C-H bond cleavage) and reformation of [Co(PCPNMe-iPr)(CO)2]. Second, C-H bond cleavage is achieved upon exposure of [Co(°3P,CH,P-P(CH)PNMe-iPr)(CO)2]+ to oxygen or TEMPO to yield the paramagnetic CoII PCP complex [Co(PCPNMe-iPr)(CO)2]+. Finally, replacement of one CO ligand in [Co(°3P,CH,P-P(CH)PNMe-iPr)(CO)2]+ by CNtBu promotes the rapid oxidative addition of the agostic η2-Caryl-H bond to give two isomeric hydride complexes of the type [Co(PCPNMe-iPr)(CNtBu)(CO)(H)]+.

KW - C-H activation

KW - agostic interactions

KW - cobalt

KW - pincer complexes

KW - protonation

UR - https://www.scopus.com/pages/publications/84959552364

U2 - 10.1002/anie.201510145

DO - 10.1002/anie.201510145

M3 - Article

AN - SCOPUS:84959552364

SN - 1433-7851

VL - 55

SP - 3045

EP - 3048

JO - Angewandte Chemie - International Edition

JF - Angewandte Chemie - International Edition

IS - 9

ER -