Methyl, iridium complex

Iridium.—Methyl complexes [IrClX(Me)(PPh3)a] (X = C1 or Br) undergo facile... 

Alkylation of thioacyl ligands provides a route to thiocarbene complexes. Faraone and co-workers have prepared iridium thiocarbene complexes 20 and 21 by methyl iodide addition to Ir(I) thiocarbonyl... 

Methyl migration to the electrophilic methylene carbon of a cationic Ir(III) complex (66) to form an iridium ethyl complex has been reported (93) ... 

Scheme 22 Catalytic cycle for the reaction of aniline with methyl cinnamyl carbonate catalyzed by a metalacyclic iridium-phosphoramidite complex...

The dimerization of functional alkenes such as acrylates and acrylonitrile represents an attractive route to obtain bifunctional compounds such as dicarboxylates and diamine, respectively. The head-to-tail dimerizahon of acrylates and vinyl ketones was catalyzed by an iridium hydride complex generated in situ from [IrCl(cod)]2 and alcohols in the presence of P(OMe)3 and Na2C03 [26]. The reaction of butyl acrylate 51 in the presence of [IrCl(cod)]2 in 1-butanol led to a head-to-tail dimer, 2-methyl-2-pentenedioic acid dibutyl ester (53%), along with butyl propionate (35%) which is formed by hydrogen transfer from 1-butanol. In order to avoid... 

Forster also reported HP IR measurements on iridium catalysed reactions [59]. It was noted that the iridium speciation is dependent on reaction conditions, with three different regimes being distinguishable. At intermediate [H2O], the dominant Ir species are [MeIr(CO)2l3] and [Ir(CO)2l4] . The anionic methyl complex is regarded as the active form of the catalyst in a cycle analogous to the Rh system, with carbonylation of [MeIr(CO)2l3] being rate determining. The Ir(III) tetraiodide... 

The reactions of butatrienylidene iridium complexes with CO depend strongly on the trans ligand. The trans chloro complex 11 reversibly adds CO to form a five-coordinate butatrienylidene complex 31 whereas the trans azido complex yields with CO an alkenyl(azido)ethynyl complex (32) and the trans methyl complex the alky-nylalkenyl complex 33 (Scheme 3.31) [3]. 

The methyl iridium dioxygen complex Ir(CH3)C0(02)[P(p-tolyl)3]2 reacts with added triphenylphosphine to produce triphenylphos-phine oxide (191). That this is a bimolecular reaction was demonstrated both by the complete absence of any oxidation of the tris(para-tolyl)-phosphine and by the lack of any substitution of the bound tris(para-tolyl)phosphine by triphenylphosphine. 

The methyl(tetrafluoroborato)iridium(III) complex is an air and moisture sensitive white crystalline solid, soluble in dichloromethane. The IR spectrum (in Nujol) shows absorptions at 2070 (vc0), 310 (vIrC1) and 1136, 908cm-1... 

The activation of methane in solution by an organometallic complex presents some experimental difficulties because any solvent that is likely to be chosen will be more reactive than methane. In addition, insolubility of the complex in liquid methane may preclude reaction with the pure hydrocarbon. These problems were overcome in the case of the reaction of CH4 with the iridium complex of Eq. 15.106 by taking advantage of the fact that the desired hydndo methyl complex Is thermodynamically more stable than other hydrido alkyl complexes. The methyl complex was produced by first creating a hydrido cyclohexyl complex and then allowing it to react with methane, m... 

At this juncture, Danishefsky decided to investigate the possibility of setting the C(ll) and C(17) methyl stereocentres of 23 by hydroxyl-directed hydrogenation.13 Some years earlier, Evans had shown that cationic rhodium- and iridium-phosphine complexes can mediate highly diastereoselective reductions of trisubstituted homoallylic alcohols. However, for excellent stereoselectivities to generally be observed, it... 

The iridium mnt complexes (13) also undergo outer-sphere ET reactions with methyl viologen (88), related in some ways to that found by Kisch and co-workers (77) for A[M(SS)2] systems via IPCT (see above). Depending on the nature of the L and L ligands in 13, the reducing ability of the metal dithiolene complex can be varied in such a manner that the ET reactions can... 

The four-coordinate iridium(I) complex [Ir(02S-p-tolyl)(CO)(PPh3)2] (70) (02S-p-tolyl = p-toluenesulfinate) has been prepared from [Ir(CO)(PPh3)2(MeCN)]+ and sodium p-toluenesul-finate.163 This complex contains an O-bonded sulfinate ligand, as indicated by IR spectral evidence.98 On addition of methyl iodide to (70), an iridium(III) complex with O-bonded sulfinate is formed. 

Homobimetallic iridium(I) complexes containing the binucleating PNNP ligand undergo oxidative addition and reductive elimination reactions with acetyl chloride and methyl iodide. Thus,... 

The catalytic cycle involves the same fundamental reaction steps as the rhodium system oxidative addition of Mel to Ir(I), followed by migratory CO insertion to form an Ir(III) acetyl complex, from which acetic acid is derived. However, there are significant differences in reactivity between analogous rhodium and iridium complexes which are important for the overall catalytic activity. In situ spectroscopy indicates that the dominant active iridium species present under catalytic conditions is the anionic Ir(III) methyl complex, [IrMe(CO)2l3] , by contrast to the rhodium system where the dominant complex is [Rh(CO)2l2] - PrMe(CO)2l3] and an inactive form of the catalyst, [Ir(CO)2l4] represent the resting states of the iridium catalyst in the anionic cycles for carbonylation and the WGSR respectively. At lower concentrations of water and iodide, [Ir(CO)3l] and [Ir(CO)3l3] are present due to the operation of related neutral cycles . 

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