Striking Differences in Properties of Geometric Isomers of [Ir(tpy)(ppy)H]+: Experimental and Computational Studies of their Hydricities, Interaction with CO2, and Photochemistry

Komal Garg, Yasuo Matsubara, Mehmed Z. Ertem, Anna Lewandowska-Andralojc, Shunsuke Sato, David J. Szalda, James Muckerman, Etsuko Fujita

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We prepared two geometric isomers of [Ir(tpy)(ppy)H]+, previously proposed as a key intermediate in the photochemical reduction of CO2 to CO, and characterized their notably different ground- and excited-state interactions with CO2 and their hydricities using experimental and computational methods. Only one isomer, C-trans-[Ir(tpy)(ppy)H]+, reacts with CO2 to generate the formato complex in the ground state, consistent with its calculated hydricity. Under photocatalytic conditions in CH3CN/TEOA, a common reactive C-trans-[Ir(tpy)(ppy)]0 species, irrespective of the starting isomer or monodentate ligand (such as hydride or Cl), reacts with CO2 and produces CO with the same catalytic efficiency.

Original languageEnglish
Pages (from-to)14128-14132
Number of pages5
JournalAngewandte Chemie - International Edition
Issue number47
Publication statusPublished - Nov 16 2015



  • CO reduction
  • homogeneous catalysis
  • hydricity
  • iridium hydrides
  • photochemistry

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis

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