%0 Journal Article
%A Hauser, Simone
A.
%A Tonner, Ralf
%A Chaplin, Adrian B.
%D 2015
%T Iridium Complexes of the Conformationally Rigid IBioxMe4 Ligand:
Hydride Complexes and Dehydrogenation of Cyclooctene
%U https://acs.figshare.com/articles/journal_contribution/Iridium_Complexes_of_the_Conformationally_Rigid_IBioxMe_sub_4_sub_Ligand_Hydride_Complexes_and_Dehydrogenation_of_Cyclooctene/2132473
%R 10.1021/acs.organomet.5b00658.s001
%2 https://ndownloader.figshare.com/files/3766291
%K ligand
%K fragment
%K equivalent reaction
%K transfer dehydrogenation
%K halogen ion abstractor
%K formation
%K monomeric 2
%K charge decomposition
%K Complex 6
%K IBioxMe 4 Ligand
%K presence
%K Na
%K reactive metal centers
%K COE
%K Iridium Complexes
%K partner IBioxMe 4
%K intramolecular activation
%K CO
%K NHC
%K CycloocteneA method
%K orthogonal arrangement
%K VE
%K Hydride Complexes
%X A method
for accessing the formally 14 VE iridium(III) hydride
fragment {Ir(IBioxMe4)2(H)2}+ (2), containing the conformationally rigid NHC
ligand IBioxMe4, is reported. Hydrogenation of trans-[Ir(IBioxMe4)2(COE)Cl] (1) in the presence of excess Na[BArF4] leads to the formation of dimeric [{Ir(IBioxMe4)2(H)2}2Cl][BArF4] (3), which is structurally fluxional in solution and
acts as a reservoir of monomeric 2 in the presence of
excess halogen ion abstractor. Stable dihydride complexes trans-[Ir(IBioxMe4)2(2,2′-bipyridine)(H)2][BArF4] (4) and [Ir(IBioxMe4)3(H)2][BArF4]
(5) were subsequently isolated through in situ trapping of 2 using 2,2′-bipyridine and IBioxMe4, respectively, and fully characterized. Using mixtures of 3 and Na[BArF4] as a latent source of 2, the reactive monomeric fragment’s reactivity was
explored with excess ethylene and cyclooctene, and trans-[Ir(IBioxMe4)2(C2H4)2][BArF4] (6) and cis-[Ir(IBioxMe4)2(COD)][BArF4] (7) were isolated, respectively, through
sacrificial hydrogenation of the alkenes. Complex 6 is
notable for the adoption of a very unusual orthogonal arrangement
of the trans-ethylene ligands in the solid state,
which has been analyzed computationally using energy and charge decomposition
(EDA-NOCV). The formation of 7 via transfer dehydrogenation
of COE highlights the ability to partner IBioxMe4 with
reactive metal centers capable of C–H bond activation, without
intramolecular activation. Reaction of 7 with CO slowly
formed trans-[Ir(IBioxMe4)2(CO)2][BArF4] (8),
but the equivalent reaction with bis-ethylene 6 was an
order of magnitude faster, quantifying the strong coordination of
COD in 7.
%I ACS Publications