Halobenzenes and Ir(I): Kinetic C−H Oxidative Addition and Thermodynamic C−Hal Oxidative Addition
摘要:
A (PNP)Ir fragment undergoes facile, room-temperature oxidative addition of C-H bonds in arenes and haloarenes in preference to aromatic carbon-halogen bonds. This preference, however, is determined to be kinetic in nature. Oxidative addition of C-Cl and C-Br is preferred thermodynamically. The products of the C-Cl or C-Br oxidative addition are separated from the C-H oxidative addition products by a high activation barrier and are only accessible at >100 degrees C. Of the C-H oxidative addition products of chlorobenzene, the isomer with the o-ClC6H4 ligand has the lowest energy.
C−H Oxidative Addition to a (PNP)Ir Center and Ligand-Induced Reversal of Benzyl/Aryl Selectivity
摘要:
The (PNP)Ir fragment displays a thermodynamic preference for the oxidative addition of aromatic vs benzylic C-H bonds. However, in the case of the mesitylene activation products, the benzylic isomer is kinetically accessible and can be trapped by an external donor ligand. The preference for the benzylic isomer in the six-coordinate Ir(III) adduct of mesitylene activation is ascribed to steric factors.
Reduction of CO<sub>2</sub>to free CO by a Pd(<scp>i</scp>)–Pd(<scp>i</scp>) dimer
作者:Chandra Mouli Palit、Daniel J. Graham、Chun-Hsing Chen、Bruce M. Foxman、Oleg V. Ozerov
DOI:10.1039/c4cc02438a
日期:——
Reaction of CO2 with a Pd(I)âPd(I) dimer supported by amido/bis(phosphine) pincer PNP ligands produces free CO in the presence of Me3SiCl and Me3SiOTf.