TY - JOUR
T1 - Catalytic alkane transfer-dehydrogenation by PSCOP iridium pincer complexes
AU - Yao, Wubing
AU - Jia, Xiangqing
AU - Leng, Xuebing
AU - Goldman, Alan S.
AU - Brookhart, Maurice
AU - Huang, Zheng
N1 - Funding Information:
We gratefully acknowledge the financial support from the National Basic Research Program of China ( 2015CB856600 ), the National Natural Science Foundation of China ( 21432011 , 21422209 ), and the National Science Foundation as part of the Center for Enabling New Technologies through Catalysis ( CENTC ), Phase II Renewal, CHE-1205189.
PY - 2016
Y1 - 2016
N2 - A series of new (tBu2PSCOPR2)IrHCl iridium complexes with ‘hybrid’ phosphinothious-phosphinite PSCOP ligands ([tBu2PSCOPR2 = 1-(SPtBu2)-3-(OPR2)-C6H4], R = tBu, 4a, R = Cy, 4b, R = iPr, 4c, and R = Et, 4d) have been synthesized and characterized. Treatment of complexes 4a–d with sodium tert-butoxide generates the active species for catalytic transfer-dehydrogenation of cyclooctane (COA) or n-octane using tert-butylethylene (TBE) as hydrogen acceptor to form cyclooctene (COE) or octenes, respectively. The catalytic activity of these complexes and the product selectivity in alkane dehydrogenation is greatly influenced by the steric properties of the pincer ligand. In general, the less sterically bulky complex exhibits higher catalytic activity than the more hindered complex. Among the new (PSCOP)Ir-type complexes, the least crowded complex (tBu2PSCOPEt2)IrHCl 4d is most active for n-octane/TBE transfer-dehydrogenation. The relatively crowded, less active, complexes (tBu2PSCOPtBu2)IrHCl (4a) and (tBu2PSCOPCy2)IrHCl (4b) exhibit high regioselectivity for α-olefin formation at the early stages of the reaction.
AB - A series of new (tBu2PSCOPR2)IrHCl iridium complexes with ‘hybrid’ phosphinothious-phosphinite PSCOP ligands ([tBu2PSCOPR2 = 1-(SPtBu2)-3-(OPR2)-C6H4], R = tBu, 4a, R = Cy, 4b, R = iPr, 4c, and R = Et, 4d) have been synthesized and characterized. Treatment of complexes 4a–d with sodium tert-butoxide generates the active species for catalytic transfer-dehydrogenation of cyclooctane (COA) or n-octane using tert-butylethylene (TBE) as hydrogen acceptor to form cyclooctene (COE) or octenes, respectively. The catalytic activity of these complexes and the product selectivity in alkane dehydrogenation is greatly influenced by the steric properties of the pincer ligand. In general, the less sterically bulky complex exhibits higher catalytic activity than the more hindered complex. Among the new (PSCOP)Ir-type complexes, the least crowded complex (tBu2PSCOPEt2)IrHCl 4d is most active for n-octane/TBE transfer-dehydrogenation. The relatively crowded, less active, complexes (tBu2PSCOPtBu2)IrHCl (4a) and (tBu2PSCOPCy2)IrHCl (4b) exhibit high regioselectivity for α-olefin formation at the early stages of the reaction.
KW - Alkane
KW - Alkene
KW - Dehydrogenation
KW - Homogeneous catalysis
KW - Iridium
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U2 - 10.1016/j.poly.2016.02.044
DO - 10.1016/j.poly.2016.02.044
M3 - Article
AN - SCOPUS:84975528004
VL - 116
SP - 12
EP - 19
JO - Polyhedron
JF - Polyhedron
SN - 0277-5387
ER -