Iridium complexes, in hydrogenation

Catalytic Activity of Cp Iridium Complexes in Hydrogen Transfer Reactions... 

I 5 Catalytic Activity of Cp Iridium Complexes in Hydrogen Transfer Reactions Table 5.3 Transfer hydrogenation of ketones and imines catalyzed by ll. "... 

Reetz showed that these complexes have substrate specificity with respect to aromatic unsaturated compounds in alkene hydrogenation [21,203]. Moreover, rhodium complexes were active in alkene hydroformylation [21,203-205], and so were platinum, rhodium and iridium complexes in hydrogenation of aromatic chloronitro compounds [206],... 

In 1996, consumption in the western world was 14.2 tonnes of rhodium and 3.8 tonnes of iridium. Unquestionably the main uses of rhodium (over 90%) are now catalytic, e.g. for the control of exhaust emissions in the car (automobile) industry and, in the form of phosphine complexes, in hydrogenation and hydroformylation reactions where it is frequently more efficient than the more commonly used cobalt catalysts. Iridium is used in the coating of anodes in chloralkali plant and as a catalyst in the production of acetic acid. It also finds small-scale applications in specialist hard alloys. 

Milestones in the development of the diphosphane family include the establishment of BINAP [10] and DuPHOS [11]. The potential offered by the chiral diphosphane complexes of ruthenium [12] and iridium [13] in hydrogenation was also recognized. In parallel inves-... 

Bolm and Lu synthesized a series of naphthalene bridged P,N type sulfoximine ligands and their iridium complexes. Asymmetric hydrogenation of quinolines was explored using these iridium complexes as catalyst, and 55 92% ee with moderate conversions were detected [18]. It was noted that iodine was also not necessary in the hydrogenation of quinolines, and the enantioselectivity was reduced when iodine was added (Scheme 10.14). 

The hydrogenation of simple olefins by lr(0) NPs dispersed in ILs depends on steric hindrance at the C=C double bond, the reactivity follows the order terminal > disubstituted > tri-substituted > tetrasubstituted (Fig. 6.9). Such an order of reactivity for olefins is the same as that of classical iridium complexes in homogeneous conditions [128]. 

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