Abstract
While attempting to prepare a series of cationic NHC-Ir complexes of general formula [(NHC)Ir(COD)](+) via the silver salt metathesis reaction of its precursor (NHC)Ir(COD)Cl in dichloromethane, we unexpectedly synthesized [(mu-Cl){(2,7-SICyNap)Ir(COD))center dot{Ag(OTf)}], a chlotide-bridged Ir-Ag adduct. This result led us to investigate the chloride abstraction from the (NHC)Ir(COD)Cl systein in detail. We show how the outcome of this ubiquitous reaction is dependent on a fine balance between the nucleophilicity of the weakly coordinating anion (WCA) and the polarity/coordinating ability of the reaction medium. A frequently encountered alternative to using silver salts is also presented and compared. The experimental difference in the reactivitieS of cationic catalysts in a representative intramolecular hydroamination reaction shows how a cationic Ir-Ag adduct can fail to deliver the reaction product through what appears to be a stabilization of the catalytically inactive iridium-silver intermediate by the educt.
| Original language | English |
|---|---|
| Pages (from-to) | 801-817 |
| Number of pages | 17 |
| Journal | Organometallics |
| Volume | 36 |
| Issue number | 4 |
| Early online date | 6 Feb 2017 |
| DOIs | |
| Publication status | Published - 27 Feb 2017 |
Cite this
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In-Depth Study on Chloride Abstractions from (NHC)Ir(COD)CI Complexes. / Sipos, Gellert; Gao, Pengchao; Foster, Daven; Skelton, Brian W.; Sobolev, Alexandre N.; Dorta, Reto.
In: Organometallics, Vol. 36, No. 4, 27.02.2017, p. 801-817.Research output: Contribution to journal › Article
TY - JOUR
T1 - In-Depth Study on Chloride Abstractions from (NHC)Ir(COD)CI Complexes
AU - Sipos, Gellert
AU - Gao, Pengchao
AU - Foster, Daven
AU - Skelton, Brian W.
AU - Sobolev, Alexandre N.
AU - Dorta, Reto
PY - 2017/2/27
Y1 - 2017/2/27
N2 - While attempting to prepare a series of cationic NHC-Ir complexes of general formula [(NHC)Ir(COD)](+) via the silver salt metathesis reaction of its precursor (NHC)Ir(COD)Cl in dichloromethane, we unexpectedly synthesized [(mu-Cl){(2,7-SICyNap)Ir(COD))center dot{Ag(OTf)}], a chlotide-bridged Ir-Ag adduct. This result led us to investigate the chloride abstraction from the (NHC)Ir(COD)Cl systein in detail. We show how the outcome of this ubiquitous reaction is dependent on a fine balance between the nucleophilicity of the weakly coordinating anion (WCA) and the polarity/coordinating ability of the reaction medium. A frequently encountered alternative to using silver salts is also presented and compared. The experimental difference in the reactivitieS of cationic catalysts in a representative intramolecular hydroamination reaction shows how a cationic Ir-Ag adduct can fail to deliver the reaction product through what appears to be a stabilization of the catalytically inactive iridium-silver intermediate by the educt.
AB - While attempting to prepare a series of cationic NHC-Ir complexes of general formula [(NHC)Ir(COD)](+) via the silver salt metathesis reaction of its precursor (NHC)Ir(COD)Cl in dichloromethane, we unexpectedly synthesized [(mu-Cl){(2,7-SICyNap)Ir(COD))center dot{Ag(OTf)}], a chlotide-bridged Ir-Ag adduct. This result led us to investigate the chloride abstraction from the (NHC)Ir(COD)Cl systein in detail. We show how the outcome of this ubiquitous reaction is dependent on a fine balance between the nucleophilicity of the weakly coordinating anion (WCA) and the polarity/coordinating ability of the reaction medium. A frequently encountered alternative to using silver salts is also presented and compared. The experimental difference in the reactivitieS of cationic catalysts in a representative intramolecular hydroamination reaction shows how a cationic Ir-Ag adduct can fail to deliver the reaction product through what appears to be a stabilization of the catalytically inactive iridium-silver intermediate by the educt.
KW - WEAKLY COORDINATING ANIONS
KW - SILVER SALT METATHESIS
KW - TRANSITION-METAL-COMPLEXES
KW - C-H FUNCTIONALIZATION
KW - RAY CRYSTAL-STRUCTURE
KW - MOLECULAR-STRUCTURE
KW - IRIDIUM COMPLEXES
KW - ENANTIOSELECTIVE HYDROGENATION
KW - STRUCTURAL-CHARACTERIZATION
KW - ASYMMETRIC HYDROAMINATION
U2 - 10.1021/acs.organomet.6b00864
DO - 10.1021/acs.organomet.6b00864
M3 - Article
VL - 36
SP - 801
EP - 817
JO - Organometallics
JF - Organometallics
SN - 0276-7333
IS - 4
ER -