TY - JOUR
T1 - Aliphatic C-H bond activation initiated by a (μ-η2: η2-peroxo)dicopper(II) complex in comparison with cumylperoxyl radical
AU - Matsumoto, Takahiro
AU - Ohkubo, Kei
AU - Honda, Kaoru
AU - Yazawa, Akiko
AU - Furutachi, Hideki
AU - Fujinami, Shuhei
AU - Fukuzumi, Shunichi
AU - Suzuki, Masatatsu
N1 - Funding Information:
We are grateful to the New Zealand Dairy Research Institute for funding most of this work. We also acknowledge financial assistance from the Foundation for Research, Science and Technology, under contract CO 1801. Theco-operation andhelp ofthe farmers of the Toenepi catchment, and their families is gratefully acknowledged. Our colleagues at AgResearch, NIWA and NZDRI provided useful comments andconstructive criticism.
PY - 2009/7/8
Y1 - 2009/7/8
N2 - A (μ-η2:η2-peroxo)dicopper(II) complex, [Cu2(H-L)(O2)]2+ (1-O2), supported by the dinucleating ligand 1,3-bis[bis(6-methyl-2-pyridylmethyl)aminomethyl] benzene (H-L) is capable of initiating C-H bond activation of a variety of external aliphatic substrates (SHn): 10-methyl-9,10-dihydroacridine (AcrH2), 1,4-cyclohexadiene (1,4-CHD), 9,10-dihydroanthracene (9,10-DHA), fluorene, tetralin, toluene, and tetrahydrofuran (THF), which have C-H bond dissociation energies (BDEs) ranging from ∼75 kcal mol-1 for 1,4-CHD to ∼92 kcal mol-1 for THF. Oxidation of SH n afforded a variety of oxidation products, such as dehydrogenation products (SH(n-2)), hydroxylated and further-oxidized products (SH(n-1)OH and SH(n-2)=O), dimers formed by coupling between substrates (H(n-1)S-SH(n-1)) and between substrate and H-L (H-L-SH(n-1)). Kinetic studies of the oxidation of the substrates initiated by 1-O2 in acetone at -70°C revealed that there is a linear correlation between the logarithms of the rate constants for oxidation of the C-H bonds of the substrates and their BDEs, except for THF. The combination of this correlation and the relatively large deuterium kinetic isotope effects (KIEs), k2H/k2D (13 for 9,10-DHA, ≳29 for toluene, and ∼34 for THF at -70°C and ∼9 for AcrH2 at -94°C) indicates that H-atom transfer (HAT) from SHn (SDn) is the rate-determining step. Kinetic studies of the oxidation of SHn by cumylperoxyl radical showed a correlation similar to that observed for 1-O2, indicating that the reactivity of 1-O2 is similar to that of cumylperoxyl radical. Thus, 1-O 2 is capable of initiating a wide range of oxidation reactions, including oxidation of aliphatic C-H bonds having BDEs from ∼75 to ∼92 kcal mol-1, hydroxylation of the m-xylyl linker of H-L, and epoxidation of styrene (Matsumoto, T.; et al. J. Am. Chem. Soc. 2006, 128, 3874).
AB - A (μ-η2:η2-peroxo)dicopper(II) complex, [Cu2(H-L)(O2)]2+ (1-O2), supported by the dinucleating ligand 1,3-bis[bis(6-methyl-2-pyridylmethyl)aminomethyl] benzene (H-L) is capable of initiating C-H bond activation of a variety of external aliphatic substrates (SHn): 10-methyl-9,10-dihydroacridine (AcrH2), 1,4-cyclohexadiene (1,4-CHD), 9,10-dihydroanthracene (9,10-DHA), fluorene, tetralin, toluene, and tetrahydrofuran (THF), which have C-H bond dissociation energies (BDEs) ranging from ∼75 kcal mol-1 for 1,4-CHD to ∼92 kcal mol-1 for THF. Oxidation of SH n afforded a variety of oxidation products, such as dehydrogenation products (SH(n-2)), hydroxylated and further-oxidized products (SH(n-1)OH and SH(n-2)=O), dimers formed by coupling between substrates (H(n-1)S-SH(n-1)) and between substrate and H-L (H-L-SH(n-1)). Kinetic studies of the oxidation of the substrates initiated by 1-O2 in acetone at -70°C revealed that there is a linear correlation between the logarithms of the rate constants for oxidation of the C-H bonds of the substrates and their BDEs, except for THF. The combination of this correlation and the relatively large deuterium kinetic isotope effects (KIEs), k2H/k2D (13 for 9,10-DHA, ≳29 for toluene, and ∼34 for THF at -70°C and ∼9 for AcrH2 at -94°C) indicates that H-atom transfer (HAT) from SHn (SDn) is the rate-determining step. Kinetic studies of the oxidation of SHn by cumylperoxyl radical showed a correlation similar to that observed for 1-O2, indicating that the reactivity of 1-O2 is similar to that of cumylperoxyl radical. Thus, 1-O 2 is capable of initiating a wide range of oxidation reactions, including oxidation of aliphatic C-H bonds having BDEs from ∼75 to ∼92 kcal mol-1, hydroxylation of the m-xylyl linker of H-L, and epoxidation of styrene (Matsumoto, T.; et al. J. Am. Chem. Soc. 2006, 128, 3874).
UR - http://www.scopus.com/inward/record.url?scp=67649986195&partnerID=8YFLogxK
U2 - 10.1021/ja809822c
DO - 10.1021/ja809822c
M3 - Article
C2 - 19530656
AN - SCOPUS:67649986195
SN - 0002-7863
VL - 131
SP - 9258
EP - 9267
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 26
ER -