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Solvent‐Dependent Structure of Iridium Dihydride Complexes: Different Geometries at Low and High Dielectricity of the Medium
Author(s) -
Polukeev Alexey V.,
Marcos Rocío,
Ahlquist Mårten S. G.,
Wendt Ola F.
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201505133
Subject(s) - iridium , chemistry , hydride , agostic interaction , trigonal bipyramidal molecular geometry , solvent , cyclohexane , crystallography , photochemistry , molecule , computational chemistry , organic chemistry , catalysis , hydrogen , metal
The hydride iridium pincer complex [(PCyP)IrH 2 ] (PCyP= cis ‐1,3‐bis[(di‐ tert ‐butylphosphino)methyl]cyclohexane, 1 ) reveals remarkably solvent‐dependent hydride chemical shifts, isotope chemical shifts, J HD and T 1 (min), with r HH increasing upon moving to more polar medium. The only known example of such behaviour (complex [(POCOP)IrH 2 ], POCOP=2,6‐( t Bu 2 PO) 2 C 6 H 3 ) 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)IrH 2 ] 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.