Synthesis and Characterization of Carbazolide-Based Iridium PNP Pincer Complexes. Mechanistic and Computational Investigation of Alkene Hydrogenation: Evidence for an Ir(III)/Ir(V)/Ir(III) Catalytic Cycle

<div>The synthesis and characterization of an iridium polyhydride complex (Ir-H4)</div><div>supported by an electron-rich PCP framework is described. This complex readily loses molecular</div><div>hydrogen allowing for rapid room temperature hydrogen isotope exchange (HIE) at the hydridic</div><div>positions and the α-C-H site of the ligand with deuterated solvents such as benzene-d6, toluene-d8</div><div>and THF-d8. The removal of 1-2 equivalents of molecular H2 forms unsaturated iridium carbene</div><div>trihydride (Ir-H3) or monohydride (Ir-H) compounds that are able to create further unsaturation</div><div>by reversibly transferring a hydride to the ligand carbene carbon. These species are highly active</div><div>hydrogen isotope exchange (HIE) catalysts using C6D6 or D2O as deuterium sources for the</div><div>deuteration of a variety of substrates. By modifying conditions to influence the Ir-Hn speciation,</div><div>deuteration levels can range from near exhaustive to selective only for sterically accessible sites.</div><div>Preparative level deuterations of select substrates were performed allowing for procurement of</div><div>>95% deuterated compounds in excellent isolated yields; the catalyst can be regenerated by</div><div>treatment of residues with H2 and is still active for further reactions.</div>

Download Full-text

Synthesis and characterization of new Pd(II) non-symmetrical Pincer complexes derived from thioether functionalized iminophosphoranes. Evaluation of their catalytic activity in the Suzuki–Miyaura couplings

Journal of Organometallic Chemistry ◽

10.1016/j.jorganchem.2013.09.038 ◽

2014 ◽

Vol 749 ◽

pp. 287-295 ◽

Cited By ~ 28

Author(s):

Sandra Ramírez-Rave ◽

Fabiola Estudiante-Negrete ◽

Rubén A. Toscano ◽

Simón Hernández-Ortega ◽

David Morales-Morales ◽

...

Keyword(s):

Catalytic Activity ◽

Pincer Complexes ◽

Synthesis And Characterization

Download Full-text

Synthesis and Characterization of Amido Pincer Complexes of Lithium and Nickel and Catalysis of the Nickel Complexes in the Kumada Cross-Coupling

Organometallics ◽

10.1021/om800580p ◽

2008 ◽

Vol 27 (21) ◽

pp. 5649-5656 ◽

Cited By ~ 27

Author(s):

Kai Sun ◽

Li Wang ◽

Zhong-Xia Wang

Keyword(s):

Nickel Complexes ◽

Cross Coupling ◽

Pincer Complexes ◽

Synthesis And Characterization

Download Full-text

Phenylsilane dehydrocoupling and addition to styrene catalyzed by (R-indenyl)Ni(phosphine)(methyl) complexes

Canadian Journal of Chemistry ◽

10.1139/v08-132 ◽

2009 ◽

Vol 87 (1) ◽

pp. 280-287 ◽

Cited By ~ 14

Author(s):

Yaofeng Chen ◽

Davit Zargarian

Keyword(s):

Solid State ◽

Nmr Spectra ◽

Variable Temperature ◽

Structural Parameters ◽

Catalytic Cycle ◽

Synthesis And Characterization ◽

H Nmr ◽

Solid State Structures ◽

Indenyl Complexes

This report describes the synthesis and characterization of the Ni–Me complexes (R-indenyl)Ni(PR′3)Me (R = 1-i-Pr, 1-SiMe3, and 1,3-(SiMe3)2; R′= Me, Ph) and outlines their catalytic reactivities in the dehydrogenative oligomerization of PhSiH3 and its addition to styrene in the absence of initiators/activators. Observation of higher hydrosilylation activities for PPh3-based compounds featuring bulky substituents on the indenyl ligand confirms earlier suggestions that phosphine dissociation is an important component of the catalytic cycle for this reaction. In contrast, oligomerization of PhSiH3 is more facile with PMe3-based precursors and independent of the steric bulk of the indenyl ligand, implying that this reaction does not involve phosphine dissociation. These conclusions are consistent with the variable-temperature 1H NMR spectra of {1,3,-(SiMe3)2-indenyl}Ni(PR′3)Me and various structural parameters observed in the solid-state structures of {1,3,-(SiMe3)2-indenyl}Ni(PPh3)Me, {1,3,-(SiMe3)2-indenyl}Ni(PMe3)Cl, and {1-SiMe3-indenyl}Ni(PMe3)Me.Key words: nickel-indenyl complexes, hydrosilylation, hydrosilane oligomerization.

Download Full-text

Monoanionic bis(carbene) pincer complexes featuring cobalt(I–III) oxidation states

Dalton Transactions ◽

10.1039/c5dt04723d ◽

2016 ◽

Vol 45 (24) ◽

pp. 9805-9811 ◽

Cited By ~ 28

Author(s):

Abdulrahman D. Ibrahim ◽

Kenan Tokmic ◽

Marshall R. Brennan ◽

Dongyoung Kim ◽

Ellen M. Matson ◽

...

Keyword(s):

Cobalt Complexes ◽

Oxidation States ◽

Pincer Complexes ◽

Synthesis And Characterization

The synthesis and characterization of a series of cobalt complexes featuring a pincer bis(carbene) ligand of the meta-phenylene-bridged bis-N-heterocyclic carbene (ArCCC, Ar = 2,6-diispropylphenyl or mesityl) are reported.

Download Full-text