Solvent‐Dependent Structure of Iridium Dihydride Complexes: Different Geometries at Low and High Dielectricity of the Medium |
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| Authors: | Dr. Alexey V. Polukeev Dr. Rocío Marcos Prof. Mårten S. G. Ahlquist Prof. Ola F. Wendt |
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| Affiliation: | 1. Centre for Analysis and Synthesis, Department of Chemistry, Lund University, PO Box 124, Lund, Sweden;2. Division of Theoretical Chemistry and Biology, School of Biotechnology, KTH Royal Institute of Technology, Stockholm, Sweden |
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| Abstract: | The hydride iridium pincer complex [(PCyP)IrH2] (PCyP=cis‐1,3‐bis[(di‐tert‐butylphosphino)methyl]cyclohexane, 1 ) reveals remarkably solvent‐dependent hydride chemical shifts, isotope chemical shifts, JHD and T1(min), with rHH increasing upon moving to more polar medium. The only known example of such behaviour (complex [(POCOP)IrH2], POCOP=2,6‐(tBu2PO)2C6H3) was explained by the coordination of a polar solvent molecule to the iridium (J. Am. Chem. Soc. 2006 , 128, 17114). Based on the existence of an agostic bond between α‐C?H and iridium in 1 in all solvents, we argue that the coordination of solvent can be rejected. DFT calculations revealed that the structures of 1 and [(POCOP)IrH2] depend on the dielectric permittivity of the medium and these compounds adopt trigonal‐bipyramidal geometries in non‐polar media and square‐pyramidal geometries in polar media. |
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| Keywords: | density functional calculations hydrides iridium pincer complexes solvent effects |
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