Mechanism of CO displacement from an unusually labile rhenium complex: An experimental and theoretical investigation

Muhammad Sohail, Veeranna Yempally, Muhammad Anas, Salvador Moncho Escriva, Samuel J. Kyran, Edward Brothers, Donald J. Darensbourg, Ashfaq A. Bengali

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The displacement of a CO ligand from an unusually labile rhenium carbonyl complex containing a bidentate carboxyaldehyde pyrrolyl ligand by PPh 3 and pyridine has been investigated. The reaction is found to proceed by an associative, preequilibrium mechanism. Theoretical calculations support the experimental data and provide a complete energetic profile for the reaction. While the Re-CO bond is found to be intrinsically weak in these complexes, it is postulated that the unusual lability of this species is due to the presence of a weak aldehyde Re-O link that can easily dissociate to open a coordination site on the metal center and accommodate an incoming ligand prior to CO loss. The resulting intermediate complex has been identified by IR spectroscopy. The presence of the hemilabile pyrrolyl ligand provides a lower-energy reaction channel for the release of CO and may be of relevance in the design of CO-releasing molecules.

Original languageEnglish
Pages (from-to)13041-13049
Number of pages9
JournalInorganic Chemistry
Issue number23
Publication statusPublished - 3 Dec 2012


ASJC Scopus subject areas

  • Inorganic Chemistry
  • Physical and Theoretical Chemistry

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