Pincer-ligated iridium complexes

Pincer-ligated iridium complexes have been used as homogeneous catalysts for the dehydrogenation of aliphatic polyalkenes to give partially unsaturated polymers. The catalyst appears to be selective for dehydrogenation in branches as compared with the backbone of the polymer.56 The mechanism shown in Scheme 1 has been suggested for an [IrCl(cod)]2-catalysed oxidative esterification reaction of aliphatic aldehydes and olefinic alcohols.57... 

Recently, metathesis of cyclooctane was reported using the tandem system having the pincer-ligated iridium complexes for hydrogenation/dehydrogenation and Schrock-type Mo-alkylidene complexes for olefin metathesis [78]. However,... 

Ray A, Zhu K, Kissin YV, Cherian AE, Coates GW, Goldman AS. Dehydrogenation of ahphatic polyolefins catalyzed by pincer-ligated iridium complexes. Chem Commun. 2005 (27) 3388-3390. 

Pincer-ligated metal complexes have displayed extraordinarily rich chemistry and have found widespread use in catalysis. Pincer complexes of numerous transition metals have been synthesized, but the most well-studied probably involve Ru, Rh, Ir, and Pd [1-7], Our group has largely focused on pincer-iridium complexes, which have shown a strong tendency toward the activation of C-H bonds. These complexes have been found to effect the oxidative addition of a variety of C-H bonds including those with sp - and sp-hybridized carbon [8-10], Most notable, however, has been the activation of C(sp )-H bonds, leading to alkane dehydrogenation [6, 7],... 

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