Reactivity of [Ir(COE)₂(solvent)₂]PF₆ Complexes toward Alkylphosphines:  Room-Temperature C−H Activation (Cyclometalation) and Isolation of a 14-Electron Alkyl−Iridium(III) Complex

Abstract

Isolated, cationic bis(cyclooctene)−Ir(I) complexes stabilized by acetonitrile or acetone solvent molecules were obtained and reacted with simple alkylphosphines, leading to selective displacement of the cyclooctene ligand. With the bulky tBu3P, facile intramolecular C−H activation is observed, giving cyclometalated, solvent-stabilized bis(phosphine)−Ir(III) species and leading to the isolation of the first 14-electron alkyl−Ir(III) complex.

Getting the sterics just right: a five-coordinate iridium trisboryl complex that reacts with C–H bonds at room temperature

“…5 Given that many nominally fivecoordinate d 6 transition metal structures are stabilized by agostic interactions from C-H bonds in their ligand periphery, 6 we have examined this possibility for 5. NMR and IR spectra lack the signatures associated with agostic C-H interactions, which is consistent with the solid state structure where the closest Ir-C distance of 3.169(9) A ˚falls outside the range of 2.65-2.94 A ˚for Ir compounds with bona fide agostic interactions, [7][8][9][10][11][12] and is B0.5 A ˚longer than the agostic C-H distances for five-coordinate Ir III examples. 7,11 Complex 5 reacts only slowly with arenes at room temperature.…”

CH Activation and CC Double Bond Formation Reactions in Iridium ortho‐Methyl Arylphosphane Complexes

“…The high-field shift of the latter signal is in agreewww.chemeurj.org ment with the presence of a d-agostic interaction as described for the 14-electron Ru II and Pt II complexes bearing PPh 2 (2,6-Me 2 C 6 H 3 ) systems. [4,5] A related coordinatively unsaturated alkyl-hydride Ir III complex with an IrHRP 2 + core has been reported by Milstein, [36] whereas IrH 2 P 2 + species stabilized by two g-agostic interactions have been described by Caulton et al [37] When a solution of 6 is gently heated (35 8C) or the dihydrogen pressure is reduced, formation of the biscyclometalated 5 species through reversible elimination of H 2 is observed. Similar behavior has been reported for the related 14-electron species [PtHA C H T U N G T R E N N U N G {PR 2 (2,6-Me 2 C 6 H 3 )}]…”

PNP-Pincer Complexes of Osmium: Comparison with Isoelectronic (PCP)Ir and (PNP)Ir+ Units

“…( t Bu 4 PNP)­IrH 2 ( 4-H 2 ) was synthesized by reaction of t Bu 4 PNP with Ir­(COE) 2 (acetone) 2 following the procedure reported by Goldberg . Ir­(COE) 2 (acetone) 2 was prepared according to the procedure reported by Milstein . Kinetic analyses were performed using the “COPASI: Biological System Simulator” program …”

“…Work is currently underway to design related pincer−Os complexes as catalysts that will exploit the favorable thermodynamics of Ir(COE) 2 (acetone) 2 was prepared according to the procedure reported by Milstein. 40 Kinetic analyses were performed using the "COPASI: Biological System Simulator" program. 41 Synthesis of ( tBu 4 PNP)OsCl 3 (1-Cl 3 ).…”