Neutral Iridium complex

Schemes 6-5 Oxidative addition of water to neutral iridium phosphine complexes...

The imidazole complex raras-[Ir(imid)2Cl4]- is stable for days in neutral aqueous solution, and for hours in the presence of added thiocyanate. Addition of silver nitrate precipitates the silver salt of the complex, with no indication of Ag+-catalyzed removal of coordinated chloride. Thus this iridium(III) complex is substitutionally much more inert than its much-studied (because (potentially) anti-tumor) ruthenium(III) analogue (96). 

Neutral iridium(I) complexes [Ir(Cl)(cod)(L)] [46] consisting of the chiral carbene ligands LI and L2 have been shown as active catalysts for the asymmetric hydrosi-... 

The complexes may be applied to some very demanding and complex transformations as illustrated by a key step in the synthesis of Bafilomycin A1 (Scheme 9), in which a neutral rhodium catalyst was employed69. In contrast, a cationic iridium-based complex was the catalyst of choice in an exacting selective homoallylic alcohol reduction to achieve a vital inversion of configuration in the synthesis of Brevetoxin B70. Functionalized alkenes may also be effectively reduced, significantly trialkylstannanes which... 

It has been found that low-valent iridium hydride complexes are effective catalysts for activation of both the a-C-H bond and the CN triple bond of nitrile. Actually, the catalytic cross condensation of nitrile 27 and nitrile 28 in the presence of IrH(CO)(PPh3)3 catalyst (29) was performed under neutral conditions to give the... 

R. Gillard and his co-workers at Kent University have extended these studies, and shown that organic complexes of rhodium produce similar effects. G. Gale and his associates at the Medical University of South Carolina developed a parallel story of the photochemical transformations and fi-lamentation of bacteria by the cA-isomer of the neutral complex with iridium instead of platinum. Thus, the experience now accumulated suggests a... 

The neutral arenediazo iridium(I) complex [Ir(Cl)(N2C5Cl4)(PPh3)2] (27) (N2C5C14 = 2,3,4,5-tetrachlorodiazocyclopentadiene) has been prepared via reaction (16). An X-ray crystal structure determination of complex (27) reveals a singly bent arenediazo ligand.60 Further, complex (27) is somewhat similar to the cationic complex [Ir(Cl)(N2Ph)(PPh3)2]+,61 in that both complexes form... 

Monsanto also discovered significant catalytic activity for iridium/iodide catalysts however, they chose to commercialize the rhodium-based process due to its higher activity under conventional high water conditions. Despite this, detailed mechanistic studies by Forster and his colleagues were undertaken at Monsanto and revealed a catalytic mechanism for iridium which is similar to the rhodium system in many respects, but with additional complexity due to participation of both anionic and neutral complexes (see below). 

The bonding in the rhodium(I) and iridium(I) complexes [M(cod)(TIME" )]PFg (M = Rh, Ir) [393] is very similar except that the metal centre requires only two monodentate ligands, which results in a monoprotonated bidentate [2+1] type hgand coordination (see Figure 3.142). Use of two metal precursors per ligand results in a [2+1] bridging coordination mode with a cationic and a neutral end (see Figure 3.143). 

The neutral complex Rh(CO)(/u.-DPPM)2lr(CO)2 is unre-active toward even excess methyl iodide but is alkylated by MeOCH2l and then methyl triflate (equation 24 (R = MeOCH2)). It can, however, be methylated at iridium by methyl triflate and the... 

Iridium(III) complexes have been widely explored in the past few decades because of their outstanding photophysical properties and superior photo- and chemical stability (123-129). Much effort has been devoted to both neutral and cationic luminescent iridium complexes in which fine-timing of the energy of their long-lived excited state can be achieved by proper choice of the coordinated ligands (130-136). 

Mehlstaubl, M., Kottas, G.S., Colella, S., and De Cola, L. (2008) Sensitized near-infrared emission from ytter-bium(III) via direct energy transfer from iridium(III) in a heterometallic neutral complex. Dalton Transactions, 2385. 

Under neutral conditions iridium hydride complexes catalyze addition between nitriles to give cyanoenamines (Sch. 40) [159]. This reaction implies simultaneous activation of both the a-C-H bond of the nitrile as a pronucleophile and the CN triple bond of the nitrile as an electrophile. 

Polyfluorenes with Neutral Iridium(III) Complexes in the Side-Chain. .. 127... 

Polyfluorenes with neutral iridium(III) complexes in the side-chain and main-chain of polymers are discussed, respectively. 

The efficacy of an iridium/iodide catalyst for methanol carbonylation was discovered by Monsanto at the same time as their development of the process using the rhodium/iodide catalyst [5]. Mechanistic investigations by Forster employing in situ HPIR spectroscopy revealed additional complexity compared to the rhodium system [115]. In particular, the carbonylation rate and catalyst speciation were found to show a more complicated dependence on process variables, and three distinct regimes of catalyst behavior were identified. At relatively low concentrations of Mel, H20, and ionic iodide, a neutral iridium (I) complex [Ir(CO)sI] was found to dominate, and the catalytic reaction was inhibited by increasing the CO partial pressure. Addition of small amounts of a quaternary ammonium iodide salt caused the dominant iridium species to become an Ir(III) methyl complex, [Ir(CO)2l3Me]. Under these conditions, the rate... 

Li(TMEDA)][PhBP3] has been prepared by addition of 3equiv. of [Li(TMEDA)][CH2PPh2] to BPhCl2. The tripodal anionic PI1BP3 has been employed in the synthesis of a neutral iridium silylene complex... 

Fig. 7.1. Synthesis of the neutral iridium silylene complex [Ir=SiMes2(H)2(PhBP3)].

Thompson and coworkers reported a ciass of neutral cyclometalated iridium(lfl) complexes [fr2 (N C)4Cl2]... 

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