Abstract
Addition of high pressures of H2 to five-coordinate [(tBu)4(POCOP)Ir(CO)(H)]OTf [(tBu)4(POCOP) = κ3-C6H3-2,6-(OP(tBu)2)2] complexes results in observation of two new iridium-dihydrogen complexes. If the aryl moiety of the POCOP ligand is substituted with an electron withdrawing protonated dimethylamino group at the para position, hydrogen coordination is enhanced. Five-coordinate Ir-H complexes generated by addition of triflic acid to (tBu)4(POCOP)Ir(CO) species show an Ir-H 1H NMR chemical shift dependence on the number of equivalents of acid present. It is proposed that excess triflic acid in solution facilitates triflate dissociation from iridium, resulting in unsaturated five-coordinate Ir-H complexes. The five-coordinate iridium-hydride complexes were found to catalyze H/D exchange between H2 and CD3OD. The existence of the dihydrogen complexes, as well as isotope exchange reactions, provide evidence for proposed ionic hydrogenation intermediates for glycerol deoxygenation.
| Original language | English |
|---|---|
| Pages (from-to) | 12638-12646 |
| Number of pages | 9 |
| Journal | Journal of the American Chemical Society |
| Volume | 139 |
| Issue number | 36 |
| DOIs | |
| Publication status | Published - Jan 1 2017 |
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ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry
Cite this
Detection of an Iridium-Dihydrogen Complex : A Proposed Intermediate in Ionic Hydrogenation. / Goldberg, Jonathan M.; Goldberg, Karen I.; Heinekey, D. Michael; Burgess, Samantha A.; Lao, David B.; Linehan, John.
In: Journal of the American Chemical Society, Vol. 139, No. 36, 01.01.2017, p. 12638-12646.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Detection of an Iridium-Dihydrogen Complex
T2 - A Proposed Intermediate in Ionic Hydrogenation
AU - Goldberg, Jonathan M.
AU - Goldberg, Karen I.
AU - Heinekey, D. Michael
AU - Burgess, Samantha A.
AU - Lao, David B.
AU - Linehan, John
PY - 2017/1/1
Y1 - 2017/1/1
N2 - Addition of high pressures of H2 to five-coordinate [(tBu)4(POCOP)Ir(CO)(H)]OTf [(tBu)4(POCOP) = κ3-C6H3-2,6-(OP(tBu)2)2] complexes results in observation of two new iridium-dihydrogen complexes. If the aryl moiety of the POCOP ligand is substituted with an electron withdrawing protonated dimethylamino group at the para position, hydrogen coordination is enhanced. Five-coordinate Ir-H complexes generated by addition of triflic acid to (tBu)4(POCOP)Ir(CO) species show an Ir-H 1H NMR chemical shift dependence on the number of equivalents of acid present. It is proposed that excess triflic acid in solution facilitates triflate dissociation from iridium, resulting in unsaturated five-coordinate Ir-H complexes. The five-coordinate iridium-hydride complexes were found to catalyze H/D exchange between H2 and CD3OD. The existence of the dihydrogen complexes, as well as isotope exchange reactions, provide evidence for proposed ionic hydrogenation intermediates for glycerol deoxygenation.
AB - Addition of high pressures of H2 to five-coordinate [(tBu)4(POCOP)Ir(CO)(H)]OTf [(tBu)4(POCOP) = κ3-C6H3-2,6-(OP(tBu)2)2] complexes results in observation of two new iridium-dihydrogen complexes. If the aryl moiety of the POCOP ligand is substituted with an electron withdrawing protonated dimethylamino group at the para position, hydrogen coordination is enhanced. Five-coordinate Ir-H complexes generated by addition of triflic acid to (tBu)4(POCOP)Ir(CO) species show an Ir-H 1H NMR chemical shift dependence on the number of equivalents of acid present. It is proposed that excess triflic acid in solution facilitates triflate dissociation from iridium, resulting in unsaturated five-coordinate Ir-H complexes. The five-coordinate iridium-hydride complexes were found to catalyze H/D exchange between H2 and CD3OD. The existence of the dihydrogen complexes, as well as isotope exchange reactions, provide evidence for proposed ionic hydrogenation intermediates for glycerol deoxygenation.
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U2 - 10.1021/jacs.7b06480
DO - 10.1021/jacs.7b06480
M3 - Article
VL - 139
SP - 12638
EP - 12646
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 36
ER -