Dehydrogenation of aliphatic polyolefins catalyzed by pincer-ligated iridium complexes

Ray, A.; Zhu, Kun; Kissin, Yury V.; Cherian, Anna E.; Coates, Geoffrey W.; Goldman, Alan S.

doi:10.1039/b502120k

Cited by 76 publications

(59 citation statements)

References 13 publications

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“…Moreover, in addition to simple al-A C H T U N G T R E N N U N G kanes, iridium pincer complexes have been reported to catalyze dehydrogenation of numerous other substrates including amines, [7] alcohols, [8] and polyolefins. [9] Mechanistic details of the dehydrogenations by both iridium PCP and POCOP pincer catalysts have been disclosed. [10] While the iridium pincer systems are quite robust, the utility of these homogeneous catalysts is limited due to problems of catalyst recyclability and product separation.…”

Section: Introductionmentioning

confidence: 99%

Highly Active and Recyclable Heterogeneous Iridium Pincer Catalysts for Transfer Dehydrogenation of Alkanes

et al. 2009

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Pincer-ligated iridium complexes have proven to be highly effective catalysts for the dehydrogenation and transfer-dehydrogenation of al-A C H T U N G T R E N N U N G kanes. Immobilization onto a solid support offers significant potential advantages in the application of such catalysts particularly with respect to catalyst separation and recycling. We describe three approaches toward such immobilization: (i) covalent attachment to a Merrifield resin, (ii) covalent bonding to silica via a pendant alkoxysilane group, and (iii) adsorption on g-alumina (g-Al 2 O 3 ), through basic functional groups on the para-position of the pincer ligand. The simplest of these approaches, adsorption on g-Al 2 O 3 , is also found to be the most effective, yielding catalysts that are robust, recyclable, and comparable to or even more active than the corresponding species in solution. Spectroscopic evidence (NMR, IR) and studies of catalytic activity support the hypothesis that binding occurs at the para-substituent and that this has only a relatively subtle and indirect influence on catalytic behavior.

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Section: Introductionmentioning

confidence: 99%

Highly Active and Recyclable Heterogeneous Iridium Pincer Catalysts for Transfer Dehydrogenation of Alkanes

et al. 2009

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“…Along with the dehydrogenation of simple alkanes with homogenous iridium catalysts, Coats and co-workers [86] reported the dehydrogenation of aliphatic polyolefins to produce unsaturated hydrocarbon polymers at 150°C using the p-methoxy-substituted (PCP)Ir catalysts 16 (Eq. (27)).…”

Section: ð25þmentioning

confidence: 99%

Catalytic alkane dehydrogenations

et al. 2015

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“…Poly(1-hexene) (PHex) and polyethylene (PE) were regioselectively dehydrogenated to generate terminal olefins, with the reaction efficiencyreaching 18 mol %and 4.4 mol %, respectively. [87,88] In the case of PHex, the terminal olefin was found to re-engage the catalyst and isomerize to generate internal olefins along the polymer side chain. Thef unctionalization approach resulted in value-added polyolefins with no observable change in the MWD of the polymer.…”

Section: Polyolefinsmentioning

confidence: 99%

C−H Functionalization of Commodity Polymers

et al. 2019

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Synthetic manipulation of polymer substrates is one of the oldest and most reliable methods to increase the functional diversity of soft materials. Modifying the chemical structure of polymers that are already produced on a commodity scale leverages the current high‐volume and low‐cost production of commodity plastics for the discovery of modern materials. A myriad of polymer C−H functionalization methods have been developed which enable the modification of material properties on both a laboratory and industrial scale. More recently, driven by advances in C−H activation, photoredox catalysis, and radical chemistry, chemoselective approaches have emerged as a means to impart precise functionality onto commodity polymer substrates. This Review discusses the historical significance of and contemporary advances in the C−H functionalization of commodity polymers. The conceptual approach outlined herein presents exciting new directions for the field, including increasing the value of otherwise pervasive materials, uncovering entirely new material properties, and a viable path to upcycle post‐consumer plastic waste.

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Dehydrogenation of aliphatic polyolefins catalyzed by pincer-ligated iridium complexes

Abstract: We report the first example of the catalytic dehydrogenation of aliphatic polyolefins to give partially unsaturated hydrocarbon polymers.

Cited by 76 publications

References 13 publications

Highly Active and Recyclable Heterogeneous Iridium Pincer Catalysts for Transfer Dehydrogenation of Alkanes

Highly Active and Recyclable Heterogeneous Iridium Pincer Catalysts for Transfer Dehydrogenation of Alkanes

Catalytic alkane dehydrogenations

C−H Functionalization of Commodity Polymers

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