Synthesis of New Iridium N-Heterocyclic Carbene Complexes and Facile Intramolecular Alkyl C−H Bond Activation Reactions of the Carbene Ligand

Abstract

The new iridium N-heterocyclic carbene complexes Cp N Ir(Ii-PrMe)I 2 and CpIr(Ii-PrMe)I 2 (Cp N ) (2-(dimethylamino)ethyl)cyclopentadienyl; Ii-PrMe ) 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) have been synthesized along with Ir(cod)(Ii-PrMe)Cl, Cp N Ir(Ii-PrMe)(η 2 -cod), and CpIr(Ii-PrMe)(η 2 -cod). Facile intramolecular alkyl C-H bond activation reactions of Cp*Ir(Ii-PrMe)Cl 2 (Cp* ) η 5 -pentamethylcyclopentadienyl) and Cp N Ir(Ii-PrMe)I 2 have occurred by treatment with MeONa and AgOTf, respectively.

Syntheses and molecular structures of 18/16-electron half-sandwich iridium(III) complexes with chelating anilido-imine ligands

“…The two Ir-N bonds in 1a (Ir(1)-N(2), 2.085(4) Å; Ir(1)-N(1), 2.106(4) Å) are distinctly shorter than those bonds in 2b (Ir(1)-N(2), 1.976(4) Å; Ir(1)-N(1), 2.007(4) Å), due to the stronger electron affinity of the metal center which takes more positive charge in complex 2b. The Ir-Cl bond in complex 1a is 2.489 Å aligned with literatures [7,8].…”

“…Molecular structure analysis reveals that 1a is neutral 18-electron species containing a chelating anilido-imine ligand, a g 5 -Pentamethylcyclopentadiene (Cp * ) group and a chloride, while 2b is a 16-electron cation with a chloride as equilibrium ion. The metal center of complex 1a adopts distorted three-leg piano stool geometry [8,9], which is different from the two-legged geometry of 2b. The dihedral angle between the Ir1-N1-C1-C2-C3-N2 plane and Cp * is 63.2°for 1a.…”

Iridium, ruthenium, and palladium complexes containing a mesoionic fused imidazolylidene ligand

“…Similarly, the imidazole 2,3-bond, which does not form part of the pyridyl framework is substantially shorter than the pyridyl a bond, pointing to a localized 2-pyridylidene unit. with ortho substituents [77,78]. The absence also directly affects the stability of the complexes.…”

Chelating N-heterocyclic carbene–carboranes offer flexible ligand coordination to IrIII, RhIII and RuII: effect of ligand cyclometallation in catalytic transfer hydrogenation

“…[33][34][35][36][37] The Ir-CH2 distance of 2.128(3) Å is moderately long compared to other Ir III -alkyl-cyclometallated complexes. 30,33,38 The carboranyl carbon atoms were determined using the VCD method, and revealed a particularly elongated B3 vertex to centroid distance of 1.89 Å, which are typically in the range 1.72-1.78 Å. 31,39 It can be proposed that the metallated carborane B vertex elongates to relieve steric encumbrance close to the metal centre.…”