Issue 5, 2018

Iridium complexes of perimidine-based N-heterocyclic carbene pincer ligands via aminal C–H activation

Abstract

The reactions of N,N′-bis(phosphinomethyl)dihydroperimidine pro-ligands H2C(NCH2PR2)2C10H6-1,8 (R = Ph 1a, R = Cy 1b) with iridium(I) substrates have been investigated and shown to readily result in chelate-assisted C–H activation processes. The reaction of 1b with [Ir2Cl2(COE)4] (COE = cyclo-octene) affords the 18-electron iridium(III) dihydrido complex [IrH2Cl{κ3-C,P,P′-C(NCH2PCy2)2C10H6}], which forms [IrHCl23-C,P,P′-C(NCH2PCy2)2C10H6}] under acidic (HCl) conditions. In contrast, reaction of 1a with [Ir2Cl2(COD)2] (COD = 1,5-cyclo-octadiene) affords the complex [IrCl(COD){κ2-P,P′-H2C(NCH2PPh2)2C10H6}], thermolysis of which affords cyclo-octene and the pincer-NHC complex [IrCl{κ3-C,P,P′-C(NCH2PPh2)2C10H6}]. The reaction of 1a with two equivalents of [Ir2Cl2(COD)2] provides the binuclear complex [Ir2{μ-H2C(NCH2PPh2)2C10H6}Cl2(COD)2] which is also observed to accumulate and then dissipate during the preceding thermolysis. Related binuclear complexes [M2{μ-H2C(NCH2PPh2)2C10H6}Cl4(η-C5Me5)2] (M = Ir, Rh) which obviate C–H activation were similarly synthesised.

Graphical abstract: Iridium complexes of perimidine-based N-heterocyclic carbene pincer ligands via aminal C–H activation

Supplementary files

Article information

Article type
Paper
Submitted
04 Dec 2017
Accepted
23 Dec 2017
First published
03 Jan 2018

Dalton Trans., 2018,47, 1577-1587

Iridium complexes of perimidine-based N-heterocyclic carbene pincer ligands via aminal C–H activation

A. F. Hill, C. Ma, C. M. A. McQueen and J. S. Ward, Dalton Trans., 2018, 47, 1577 DOI: 10.1039/C7DT04572G

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