Electrophilic Organoiridium(III) Pincer Complexes on Sulfated Zirconia for Hydrocarbon Activation and Functionalization

Date

2019-04-17

Author

Syed, Zoha H.
Kaphan, David M.
Perras, Frédéric A.
Pruski, Marek
Ferrandon, Magali S.
Wegener, Evan C.
Çelik, Gökhan
Wen, Jianguo
Liu, Cong
Dogan, Fulya
Goldberg, Karen I.
Delferro, Massimiliano

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Single-site supported organometallic catalysts bring together the favorable aspects of homogeneous and heterogeneous catalysis while offering opportunities to investigate the impact of metal–support interactions on reactivity. We report a (dmPhebox)Ir(III) (dmPhebox = 2,6-bis(4,4-dimethyloxazolinyl)-3,5-dimethylphenyl) complex chemisorbed on sulfated zirconia, the molecular precursor for which was previously applied to hydrocarbon functionalization. Spectroscopic methods such as diffuse reflectance infrared Fourier transformation spectroscopy (DRIFTS), dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR) spectroscopy, and X-ray absorption spectroscopy (XAS) were used to characterize the supported species. Tetrabutylammonium acetate was found to remove the organometallic species from the surface, enabling solution-phase analytical techniques in conjunction with traditional surface methods. Cationic character was imparted to the iridium center by its grafting onto sulfated zirconia, imbuing high levels of activity in electrophilic C–H bond functionalization reactions such as the stoichiometric dehydrogenation of alkanes, with density functional theory (DFT) calculations showing a lower barrier for β-H elimination. Catalytic hydrogenation of olefins was also facilitated by the sulfated zirconia-supported (dmPhebox)Ir(III) complex, while the homologous complex on silica was inactive under comparable conditions.

Subject Keywords

Colloid and Surface Chemistry, Biochemistry, General Chemistry, Catalysis

URI

https://hdl.handle.net/11511/36616

Journal

Journal of the American Chemical Society

DOI

https://doi.org/10.1021/jacs.9b00896

Collections

Department of Chemical Engineering, Article

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Citation Formats

Z. H. Syed et al., “Electrophilic Organoiridium(III) Pincer Complexes on Sulfated Zirconia for Hydrocarbon Activation and Functionalization,” Journal of the American Chemical Society, pp. 6325–6337, 2019, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/36616.