Comparison of the Reactivity of M(allyl)₃ (M = Rh, Ir) with Donor Ligands

Abstract

Reactions of M(allyl) 3 [M ) Rh, Ir] with a variety of donor ligands have been investigated. While both complexes are unreactive toward "hard" N-and O-donor ligands, "soft" ligands such as tolylisothiocyanate, tertiary phosphines, CO, and aryl isocyanides are readily added. Whereas ligand additions to Rh(allyl) 3 are often accompanied by reduction of the Rh(III) center, analogous reactions with Ir(allyl) 3 afford stable trivalent products containing σ-allyl ligands. The molecular structures of several derivatives are presented, including Ir(σ-allyl)-(π-allyl) 2 (PPh 3 ), Ir(σ-allyl) 2 (π-allyl)(PMe 3 ) 2 , and Ir(σ-allyl) 3 (CtN-2,6-Me 2 C 6 H 3 ) 3 .

Synthesis and structural aspects of M-allyl (M=Ir, Rh) complexes

“…It has also been shown that the bulky ligand substituents can cause modifications to the structure and solution behaviour of the stable allylic metal complexes [6]. The reactivity of rhodium and iridium allylic complexes with various substrates as reactants has been reported [7]. The catalytic asymmetric hydrogenation of a-functionalized ketones using chiral Ru(II)-allyl complexes has also been reported [8].…”

Highly Efficient Blue‐Emitting Iridium(III) Carbene Complexes and Phosphorescent OLEDs

“…With the aim of continuing this effort, we report herein the use of a different functionalized benzyl carbene chelate ligand and its coordination to a different iridium source reagent, namely [IrCl 3 (tht) 3 ] (tht = tetrahydrothiophene), [11] which is soluble in non-polar organic solvents. This change of reagents allows the preparation of blue-emitting Ir III complexes in a two-step synthetic manipulation involving: 1) generation of the cationic silver carbene intermediate, [12] and 2) carbene transfer [13] to the Ir III center and cyclometalation, followed by addition of the third, pyridyl azolate chelate ligand.…”

“…This concept has proved to be successful for the synthesis of a series of phosphorescent Ir III complexes. [10] Unfortunately, due to the twisting motion of the chelate ligands, which facilitates the nonradiative decay channels, these complexes do not serve as efficient true-blue phosphors but instead have been applied as the host materials for green phosphorescent OLEDs.With the aim of continuing this effort, we report herein the use of a different functionalized benzyl carbene chelate ligand and its coordination to a different iridium source reagent, namely [IrCl 3 (tht) 3 ] (tht = tetrahydrothiophene), [11] which is soluble in non-polar organic solvents. This change of reagents allows the preparation of blue-emitting Ir III complexes in a two-step synthetic manipulation involving: 1) generation of the cationic silver carbene intermediate, [12] and 2) carbene transfer [13] to the Ir III center and cyclometalation, followed by addition of the third, pyridyl azolate chelate ligand.…”

Highly Efficient Blue‐Emitting Iridium(III) Carbene Complexes and Phosphorescent OLEDs

“…With the aim of continuing this effort, we report herein the use of a different functionalized benzyl carbene chelate ligand and its coordination to a different iridium source reagent, namely [IrCl 3 (tht) 3 ] (tht=tetrahydrothiophene),11 which is soluble in non‐polar organic solvents. This change of reagents allows the preparation of blue‐emitting Ir III complexes in a two‐step synthetic manipulation involving: 1) generation of the cationic silver carbene intermediate,12 and 2) carbene transfer13 to the Ir III center and cyclometalation, followed by addition of the third, pyridyl azolate chelate ligand 14.…”