Iridium complexes structures

The five-coordinate iridium complexes may be protonated by glacial acetic acid, yielding [Ir(PPh3)2(CNR)3H] + the structure of this complex is determined by PMR measurements to be (XXIX). However, in the analogous HCl reaction [Ir(PPh3)2(CNR)2Cl2] is obtained. The reaction of [Ir(PPh3)2(CNR)3] with methanol also proved quite out of the ordinary. 

Structural studies on the nature of the organometallic intermediates following chelation-assisted CH additions of pincer iridium complexes have been carried out. The product was found to have an unexpected /ram-disposition of the hydride with respect to the metallated aromatic group. This is not the expected direct outcome of a chelation-assisted reaction since coordination of oxygen to iridium prior to C-H activation would be expected to afford the m-isorner (Equation (97)). 

SCHEME 3.86 Chemical structures of some phenylisoquinoline iridium complexes. 

As the EL efficiency is limited by the poor phosphorescent dopant PtOEP, by using a good red phosphorescent iridium complex, Liu et al. demonstrated a very highly efficient PHOLED by applying a HBM [350], The device structure is ITO/NPD/CBP 6% Ir(piq-F)3/BCP/Alq3/Mg Ag. 

The phosphoramidite ligands that are the focus of the remainder of this chapter have prompted the investigation of ligands containing related structures. Iridium complexes of aspartic acid-derived P-chirogenic diaminophosphine oxides (DlAPHOXs) catalyze the amination [62] and alkylation [63] of aUyhc carbonates (Scheme 6). With BSA as base and catalytic amounts of NaPFs as additive, branched amination and alkylation products were obtained from cinnamyl carbonates in excellent yields and enantioselectivities. However, the yields and enantios-electivities were lower for the reactions of alkyl-substituted aUyhc carbonates. Added LiOAc increased the enantioselectivities of aUyhc alkylation products. 

New N-heterocyclic carbene rhodium and iridium complexes derived from 2,2 -diaminobiphenyl were successfully synthesized and their structures unambiguously characterized by X-ray diffraction (XRD) analysis. These are cata-lytically active for the hydrosilylation of ketones with diphenylsilane, although an NHC—rhodium complex was found to be the best among those investigated [45]. 

It is no coincidence that the first X-ray structure analysis of a transition metal-boryl complex [8] was made on the iridium complex jac-[IrH2(BC8Hi4)(PMe3)3] (2) [9] derived from the B—H activation of the 9-borabicyclo[3.3.1]-nonane (9-BBN)... 

TABLE 4.3. Strength of Intramolecular Dihydrogen Bonding in Iridium Hydride Complexes (Structure 4.3) as a Function of the Nature of the frans-Ligand Y... 

The x-ray structure obtained for one of two possible isomers of the cationic iridium hydride complex [Structure 5.9(a)] exhibited two short N-H- -H-lr contacts of 1.75 0.05 A. These distances are significantly smaller than the sum... 

Short H- -H distances have been measured by H ri,min NMR relaxation in CD2CI2 solutions of complex 9 (1.82 0.05 A) in Structure 5.10 [22] and also for other closely related iridium complexes [23], where the distances were between 1.9 0.1 and 2.1 0.1 A. 

It is worth mentioning that the dihydrogen bond in solid complex 9 is elongated to 2.0 A versus 1.82 A in solution. According to the x-ray molecular structure, this effect correlates with the appearance of an additional contact between the NH proton and the [BF4] anion through the F atom due to a bifurcated bonding Ir-H- H(N)- F-B. The related iridium complexes have shown the same effects. 

---