Unsymmetrically Substituted Iridium(III)−Carbene Complexes by a CH-Activation Process

Abstract

The synthesis of the metalhydride Cp*(L′)) is achieved by a cyclohexane to cyclohexene transformation at the N-heterocyclic carbene ligand based on a CH-activation/β-hydrogen migration process at the Ir(III) center under mild conditions. The synthetic route to Cp*-(L′)IrH + OTfand NMR spectroscopic and X-ray structural data are presented.

N‐Heterocyclic Carbene Functionalized Iridium Phosphinidene Complex [Cp*(NHC)IrPMes*]: Comparison of Phosphinidene, Imido, and Carbene Complexes

“…[17a,b] The IrÀC(NHC) bond lengths of 4 ± 6 range from 1.970 ± 1.989 ä, which is in good agreement with an experimentally reported IrÀC(NHC) bond length of 2.019 ä. [14] These distances are shortened with respect to normal Ir À C single bonds ($ 2.1 ä) [18] and longer than IrC double bonds. [12] The latter can be illustrated by the short IrC distance in 6 (1.890 ä) which agrees well with the experimentally known Ir alkylidene complex [Cp*(PiPr 3 )IrCPh 2 ] (1.904 ä).…”

“…Furthermore, structural and bonding properties for the iridium phosphinidene parent complex that contains the imidazol-2-ylidene ligand is evaluated theoretically, and comparisons are made with analogous alkylidene and imido complexes. The transition metal iridium is used because similar alkylidene, [11,12] imido, [13] phosphinidene, [9] as well as N-heterocyclic carbene complexes [14] are known experimentally for iridium. [14] and confirms the presence of the carbene moiety in 2.…”

Intramolecular Alkyl Phosphine Dehydrogenation in Cationic Rhodium Complexes of Tris(cyclopentylphosphine)

“…Examples of intramolecular dehydrogenation from alkyl phosphines [9][10][11][12] (e.g. I, [13,14] II, [15,16] III [17,18] ) and betadiketimates (IV [19][20][21] ) are well-established; and other coordinated ligands, such as ethers, [22] alkoxides, [23] N-heterocyclic carbenes [24] and functionalised cyclopentadienyls [25] also undergo dehydrogenation. The intramolecular dehydrogenation of alkyl groups can also result in the addition of useful double-bond functionality that can be utilised for further elaborations in a synthetic scheme.…”

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.…”