Iridium dinuclear

The dinuclear octacarbonyls are obtained by heating the metal (or in the case of iridium, IrCl3 -I- copper metal) under a high pressure of CO (200-300 atm). Co2(CO)s is by for the best known, the other two being poorly characterized it is an air-sensitive, orange-red solid melting at... 

Complex [(CXI )Ir(/j,-pz)(/i,-SBu )(/j,-Ph2PCH2PPh2)Ir(CO)] reacts with iodine to form 202 (X = I) as the typical iridium(II)-iridium(II) symmetrical species [90ICA(178)179]. The terminal iodide ligands can be readily displaced in reactions with silversalts. Thus, 202 (X = I), upon reaction with silver nitrate, produces 202 (X = ONO2). Complex [(OC)Ir(/i,-pz )(/z-SBu )(/i-Ph2PCH2PPh2)Ir(CO)] reacts with mercury dichloride to form 203, traditionally interpreted as the product of oxidative addition to one iridium atom and simultaneous Lewis acid-base interaction with the other. The rhodium /i-pyrazolato derivative is prepared in a similar way. Unexpectedly, the iridium /z-pyrazolato analog in similar conditions produces mercury(I) chloride and forms the dinuclear complex 204. 

The dinuclear iridium(l) diphosphine complexes 42 can also activate carboxylic acids easily. For example, the reaction of [IrCl(binap)]2 (42b) with an excess of acetic acid or benzoic acid in toluene at room temperature gave the corresponding (hydri-... 

The most fundamental reaction is the alkylation of benzene with ethene.38,38a-38c Arylation of inactivated alkenes with inactivated arenes proceeds with the aid of a binuclear Ir(m) catalyst, [Ir(/x-acac-0,0,C3)(acac-0,0)(acac-C3)]2, to afford anti-Markovnikov hydroarylation products (Equation (33)). The iridium-catalyzed reaction of benzene with ethene at 180 °G for 3 h gives ethylbenzene (TN = 455, TOF = 0.0421 s 1). The reaction of benzene with propene leads to the formation of /z-propylbenzene and isopropylbenzene in 61% and 39% selectivities (TN = 13, TOF = 0.0110s-1). The catalytic reaction of the dinuclear Ir complex is shown to proceed via the formation of a mononuclear bis-acac-0,0 phenyl-Ir(m) species.388 The interesting aspect is the lack of /3-hydride elimination from the aryliridium intermediates giving the olefinic products. The reaction of substituted arenes with olefins provides a mixture of regioisomers. For example, the reaction of toluene with ethene affords m- and />-isomers in 63% and 37% selectivity, respectively. 

Other 2, 2 -disubstitued biferrocene derivatives (ligands 2, Fig. 3) also tested using the dinuclear [Ir( r-Cl)(COD)]2 as the iridium source provided total conversion in arylimine hydrogenation, although with poor-to-moderate enantioselectivity (20-33% ee) [17]. The low enantioselectivies are assumed to be related to the conformational flexibility of this type of bifep ligands. 

Iridium(O).—The first dinuclear trifluorophosphine complex of Ir has been prepared by elimination of H from IrH(PF3)4 ... 

Ferrocenoylamino acids have been converted into 2-ferrocenyl-5(477)-oxazo-lones 348 and 350 that act as N donors in palladium, platinum, and iridium complexes. Reaction of 348 with chloro-bridged palladium(II) and platinum(II) complexes affords a series of N-coordinated oxazolone complexes 349. Reaction of the unsubstituted 2-ferrocenyl-5(477)-oxazolone 350 with the chloro-bridged iridium(III) complex [(ri -C5Me5)IrCl2]2 produces a dinuclear complex 351, analogous to that obtained from 2-phenyl-5(477)-oxazolone (Scheme 7.113)." ° ... 

IX. Equilibria between Mono- and Dihydroxo-Bridged Dinuclear Complexes of Chromium(III), Rhodium(III), and Iridium(III)... 

Finally it should be mentioned that several dinuclear trihydroxo-bridged //5-pentamethylcyclopentadienylrhodium(III) and iridium(III)... 

Scheme 6. Reaction scheme for the equilibria between dinuclear mono- and dihydroxo-bridged species of chromium (III), rhodium(III), and iridium(III).

In the hope of obtaining iridium methyl compounds, the dinuclear doubly methylene-bridged derivative of composition [(//-CH2)Ir(COD)]2 (75) appeared as the ultimate product of the reaction of [(COD)Ir(//-Cl)]2 with methyllithium this contrasts with the formation of [(/u.-CH3)(COD)Rh]2 from LiCH3 and [(1.5-COD)Rh(/a-Cl)]2 (185). 

Amido-bridged dinuclear iridium complexes, preparation,... 

Bis[iV,iV -di(2-pyridyl)-imidazol-2-ylidene]aurate(I) tetrafluoroborates, preparation, 2, 292-293 Bis[iV,iV -di(2-pyridyl-methyl)-imidazol-2-ylidene]aurate(I) tetrafluoroborates, preparation, 2, 292-293 Bis(diselenolate) complexes, dinuclear iron compounds, 6, 242 Bis(dithiolene) compounds, in tungsten carbonyl and isocyanide complexes, 5, 644 Bis(enolato) complexes, with bis-Cp Ti(IV), 4, 589 Bis(enones), in reductive cyclizations, 10, 502 Bis(ethanethiolato) complexes, with bis-Cp Ti(IV), 4, 601 Bis(ethene)iridium complexes, preparation, 7, 328-329 -Bis(fluorenyl)zirconocene dichlorides, preparation,... 

Dinuclear iridium alkynyl complexes, synthesis and characteristics, 7, 331... 

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