著者

Dong-Heon Lee Narasimha N. Murthy Kenneth D. Karlin

出版者

(社)日本化学会

雑誌

Bulletin of the Chemical Society of Japan (ISSN:00092673)

巻号頁・発行日

vol.80, no.4, pp.732-742, 2007-04-15 (Released:2007-04-13)

参考文献数

80

被引用文献数

6

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Copper(I)–dioxygen reactivity studies utilizing new binucleating ligands are described. When catalytic quantities of either CuI or CuII salts were introduced to LH2, which is a dinucleating ligand with two tridentate donors connected via a methylene group at a bis(2-pyridyl)methane junction, dioxygen addition caused complete oxygenation to give bis(2-pyridyl)ketone product L=O. Isolated dicopper(I) complex [CuI2(LH2)]2+ (1) also reacted with excess O2 to give L=O. Additional observations were consistent with a mechanism that does not involve “oxygen-activation” in this process. Ketone hydration and gem-diol(ate) copper(II)-coordination occurred by addition of copper(II)–perchlorate to L=O, giving [CuII2{L(OH)(O−)}Cu2II(−OClO3)]2+ (4), with a bridging alkoxide moiety (X-ray). Oxygenation of [CuI2(L=O)(CH3CN)2]2+ (2) (2/O2 = 0.5, i.e., Cu/O2 = 4:1 manometry), gave [CuII2{L(O−)2}(−OClO3)]+ (5), where both oxygen atoms of the doubly deprotonated gem-diolate bind separate copper(II) ions; mass spectrometric data showed that one of the two oxygen atoms of the gem-diolate L(O−)2 came from O2. An oxo–dicopper(II) species is suggested as an important intermediate, which is supported by the observation that reaction of 2 with NO or iodosylbenzene also produced 5 in high yields. Complexes 4 and 5 are acid–base conjugate pairs and can be readily interconverted using Et3N or HClO4(aq) reagents.