Advances in the synthesis and application of iridium (I) complexes for use in hydrogen isotope exchange

Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 2012
Thesis identifier
  • T13502
Person Identifier (Local)
  • 200857704
Qualification Level
Qualification Name
Department, School or Faculty
  • Investigations into the application of catalysts of the type [Ir(COD)(PR₃)(IMes)]PF₆ in the field of hydrogen isotope exchange have been undertaken. In particular, the use of alternative solvents has been examined, resulting in the identification of reaction media considered more industrially acceptable than those currently utilised in isotopic labelling processes. Following a series of optimisation studies, the newly developed conditions for H-D exchange were applied to a range of substrates containing a variety of functional groups. In the majority of instances, high levels of deuteration were achieved in reactions employing low catalyst loadings and short reaction times. With regards to the iridium complexes themselves, focus has centred on the introduction of alternative NHC ligands, leading to the synthesis of six novel Ir(I) catalysts. These complexes have been employed in hydrogen isotope exchange reactions, demonstrating high activity in the isotopic labelling of numerous substrates. As a result of such explorations, increased levels of selectivity have been achieved in compounds offering multiple sites of labelling, with catalysts displaying a greater preference for exchange via a 5-mmi over the less energetically favourable 6-mmi. In addition, a catalyst capable of facilitating higher levels of isotope incorporation adjacent to a sulfonamide moiety has been accomplished. A series of DFT studies have also been undertaken. The calculation of solvent binding energies to the iridium complex has revealed a broad correlation between the strength with which solvent molecules coordinate to the metal centre, and the degree of isotope incorporation observed. Further theoretical investigations were performed regarding our novel Ir(I) complexes bearing alternative NHC ligands. More specifically, computational experiments have identified the relative energies of the key processes which occur within the catalytic cycle.
Advisor / supervisor
  • Kerr, William
Resource Type