Cyclometalation via Carbon–Fluorine Bond Activation Induced by Silver Particles

Abstract

On treatment with either freshly-prepared silver nanoparticles or silver particles mechanochemically generated by stirring silver(I) oxide in dichloromethane, the complex [Cp*IrCl2(κC-MeNC3H2NCH2C6F5)] underwent a rapid and clean cyclometallation involving carbon-fluorine bond fission to afford the product [Cp*IrCl(κC 2-MeNC3H2NCH2C6F4)].

Orthometallation in iridium N-heterocycle stabilized carbene complexes via carbon halogen and carbon hydrogen bond activation induced by silver nanoparticles

“…The crystal structures of the co-crystals were modelled with 3b:3c, 3b:3d and 3b:3e ratios of 44:56, 43:57 and 64:36 respectively, without the inclusion of solvent, although residual electron density suggested the presence of a small amount (< 0.1 molecule per molecule of product). The bond distances and angles around iridium (Table 2) are similar to those of [Cp*IrCl(κC 2 -MeNC 3 H 2 NCH 2 C 6 F 4 )] [9]. 274 kJ mol -1 [16]).…”

“…Recently we reported the orthometallation of [Cp*IrCl 2 (κC-MeNC 3 H 2 NCH 2 C 6 F 5 )] via carbon─fluorine bond activation on treatment with silver particles or nanoparticles [9]. In order to determine whether the combination of [Cp*IrX 2 (NHC)] and silver particles could also activate carbon─hydrogen and other carbon─halogen bonds we chose to investigate the 2-fluorophenylmethyl and 2-halo-6-fluorophenylmethyl analogues.…”

Conversion of haloform to carbonate by iridium N-heterocyclic carbene complexes and silver(i) oxide

“…Andrew C. Marr , a Patrick J. Morgan, a Graham C. Saunders * b and Hayden P. Thomas b The reaction between haloform, the complexes [Cp*IrCl 2 (κC-MeNC 3 H 2 NCH 2 Ar)] (Ar = C 6 H 3 F 2 -2,6, C 6 Pentamethylcyclopentadienyl imidazol-2-ylidene iridium complexes, Cp*Ir(NHC), display interesting reactivity, such as activation of alkyl carbon-hydrogen bonds 1,2 and carbonfluorine bonds, 3 and catalytic activity, including water oxidation, 4,5 transfer hydrogenation, 6,7 dynamic kinetic resolution, 8 hydrogen transfer initiated dehydration, 9 the alkylation of amines, 10 and dehydrogenative oxidation of alcohols. 11 Cyclometallation involving carbon-hydrogen bond activation induced by base has been reported for NHC ligands bearing aryl, benzyl and alkyl substituents.…”

“…2,4,11,12 Recently we reported cyclometallation by carbon-halogen bond activation induced by silver particles for complexes with halogen atoms at both ortho positions of a benzyl substituent. 3,13 In a number of in situ NMR studies of carbon-halogen bond activation other minor products were formed when the silver particles were generated mechanically from silver(I) oxide. 3 It was considered possible that these were formed by a reaction between the iridium complex and residual silver(I) oxide.…”

“…3,13 In a number of in situ NMR studies of carbon-halogen bond activation other minor products were formed when the silver particles were generated mechanically from silver(I) oxide. 3 It was considered possible that these were formed by a reaction between the iridium complex and residual silver(I) oxide. In situ NMR experiments, conducted without excluding air and moisture, confirmed that, on treatment with silver(I) oxide, the complex [Cp*IrCl 2 (κC-MeNC 3 H 2 NCH 2 C 6 H 3 F-2-Cl-6)] (1a) 13 in deutero-chloroform underwent a reaction over several hours to afford the carbonate complex [Cp*Ir(κ 2 O-CO 3 )(κC-MeNC 3 H 2 NCH 2 C 6 H 3 F-2-Cl-6)] (2a) cleanly in high yield.…”