Cyclometalated iridium containing

A wide range of carbon, nitrogen, and oxygen nucleophiles react with allylic esters in the presence of iridium catalysts to form branched allylic substitution products. The bulk of the recent literature on iridium-catalyzed allylic substitution has focused on catalysts derived from [Ir(COD)Cl]2 and phosphoramidite ligands. These complexes catalyze the formation of enantiomerically enriched allylic amines, allylic ethers, and (3-branched y-8 unsaturated carbonyl compounds. The latest generation and most commonly used of these catalysts (Scheme 1) consists of a cyclometalated iridium-phosphoramidite core chelated by 1,5-cyclooctadiene. A fifth coordination site is occupied in catalyst precursors by an additional -phosphoramidite or ethylene. The phosphoramidite that is used to generate the metalacyclic core typically contains one BlNOLate and one bis-arylethylamino group on phosphorus. 

Luminescent cyclometallated iridium(III) complexes containing an extended planar diimine ligand, [Ir(ppy)2(NAN)]+ (27) (NAN = dpq, dpqa, dppz, dppn), have been synthesised and their photophysical properties studied [66], The complexes display long-lived green to orange 3MLCT (dTi(Ir) —> ji (NaN)) luminescence under ambient conditions but do not emit in aqueous solution. The binding of these complexes to... 

The moderately emissive bis(cyclometallated)iridium(III) complexes [Ir(ppy)2 (solvent)2]+ (solvent = H20, CH3CN) (33) contain weakly bound solvent molecules that can be readily displaced by histidine, resulting in the formation of a strongly blue-emitting [Ir(ppy)2(histidine)2]+ complex [75], This property allows the solvato... 

Four luminescent cyclometallated iridium(III) diimine complexes [Ir(ppy-spacer-biotin)2(NAN)]+ (NAN = Me4-phen, Ph2-phen) (38), each containing two biotin units, have been synthesised and characterised by Lo and co-workers [79], Photoexcitation of these iridium(III) diimine bis(biotin) complexes in fluid solutions at 298 K and in alcohol glass at 77 K results in intense and long-lived 3MLCT (djr(Ir) — ti (NaN))/3IL (ir —> ji ) (Me4-phen) emission. HABA assays and emission titrations indicate that the two biotin moieties of each complex are functional. RET-based emission-quenching experiments, microscopy studies using avidin-conjugated microspheres, and HPLC analysis all reveal that the complexes with a... 

Figure 22 (a) Photochromism of dithienyl-substituted 2-(2-pyridyl)imidazole ligands and their rheninm(I) tricarbonyl complexes. P. H.-M. Lee et al. (2001). Reprodnced by permission of American Chemical Society. (b) Strnctnre of diarylethene-containing cyclometallated iridium(ni) complex. (Reproduced from Ref. 48. American Chemical Society, 2009.)... 

Phenyl- and 2-naphthylbenzothiazole with iridium(III) chloride give cyclometallated derivatives of the type 54 containing two chloride bridging ligands (01IC1704). 

Concurrent with studies on cyclometalation, studies on the effects of the structure of phosphoramidite ligand had been conducted. Several groups studied the effect of the stmcmre of ligand on the rate and selectivity of these iridium-catalyzed allylic substitutions. LI contains three separate chiral components - the two phenethyl moieties on the amine as well as the axially chiral BINOL backbone. These portions of the catalyst structure can control reaction rates by affecting the rate of cyclometalation, by inhibiting catalyst decomposition, or by forming a complex that reacts faster in the mmover-limiting step(s) of the catalytic cycle. 

AN IRIDIUM(III) COMPLEX CONTAINING CYCLOMETALLATED TRIPHENYLPHOSPHINE FORMED BY ISOMERIZATION OF AN IRIDIUM(I) TRIPHENYLPHOSPHINE COMPLEX... 

Neve, F Crispini, A. Serroni, S. Loiseau, F. Campagna, S. (2001). Novel dinuclear luminescent compounds based on iridium(III) cyclometalated chromophores and containing bridging ligands with ester-linked chelating sites. Inorganic Chemistry, Vol. 40, pp. 1093-1101. 

Luminescent organometallic complexes used for cell imaging can be divided in two main families, namely (i) carbonyl complexes, most commonly octahedral rhenium c-tricarbonyl derivatives incorporating a polypyridine ligand and (ii) cyclometalated complexes such as iridium and platinum derivatives containing the ubiquitous 2-phenylpyridine unit (complexes 1-3 in Scheme 11.2). 

Cohen and coworkers have prepared zinc and zirconium MOFs containing 2-phenylpyridine-5,4 -dicarboxylate (dcppy) and shown they undergo cyclometalation reactions to introduce iridium and rhodium (equation 17) fragments. ... 

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