H/D exchange under mild conditions in arenes and unactivated alkanes with C₆D₆ and D₂O using rigid, electron-rich iridium PCP pincer complexes

Abstract

The synthesis and characterization of an iridium polyhydride complex (Ir-H4) supported by an electron-rich PCP framework and capable of mild hydrogen/deuterium exchange catalysis is described.

Access to and Reactivity of Fe0, Fe−I, FeI, and FeII PCcarbeneP Pincer Complexes

“…Protonation of the carbenic site stands in stark contrast to isoelectronic d 8 group 9a nd 10 complexes (found to have poorly nucleophilic carbene sites), and more closely mirrors the reactivity observed in zero valent group 10 PC carbene P complexes.H owever,t he carbene linkage in compound 1 appears to be much more stable than those reported for d 10 PC carbene Pcomplexes.For example,incontrast to Ni and Pd PC carbene Pp incer complexes reported by Piers and Iluc, [6] compound 1 was found to be stable in the presence of water, alcohol, amine and hydrosilane.…”

“…The ability of 1 to isomerize to form a 16 valence e − metal complex is key to its reactivity. Although PC carbene P pincers have been observed to sequester hydride ligands to enhance reactivity at a metal centre, [6e] this example is unique in that the migration of CO to the carbene position still allows bond addition across the metal‐carbon linkage (i.e. metal‐ligand cooperativity, TS II , Scheme 4).…”

“…[5] Metal alkylidenes readily undergo 1,2-additions with av ariety of strong bonds,t hus C-H, Si-H, H-H and N-H bond activations have been reported in PC carbene Pc omplexes. [6] However, PC carbene Pc omplexes have also demonstrated metal-ligand cooperation in [2+ +2] cycloadditions, [7] frustrated Lewis pair chemistry, [8] redox chemistry, [9] catalytic deoxygenation and dechalcogenation chemistry, [10] and ligand directed bond activation. [11] Further, reports of bond activation and catalysis where the ligand acts only to support the metal fragment are also known.…”

α‐ and β‐Eliminations in Transition Metal Complexes: Strategies to Cleave Unstrained C−C and C−F Bonds

“…However, also for other late metals α‐H‐elimination has been reported in works from e. g. Shaw in which PC(sp 3 )P ligand 53 reacts with IrCl 3 to generate iridium hydrido chloride complex 54 , and subsequently iridium carbene 55 is generated upon heating complex 54 ( Scheme 10). [38–43] …”

Synthesis and reactivity of PC(sp3)P-pincer iridium complexes bearing a diborylmethyl anion

“…It should be noted that intermediate 15 , which is formed after the oxidative addition of C–D bonds to intermediate 12 , could not be located on calculation as a feasible intermediate (see ESI section SIV–III† for further discussions and detailed calculation data). 10 g , m , p ,15,16…”