Structural Characterization and Oxidation Activity of a Nickel(II) Alkylperoxo Complex
Structural Characterization and Oxidation Activity of a Nickel(II) Alkylperoxo Complex
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DOI：
10.1002/anie.200804402
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发表时间：
2009-01-01
影响因子：
16.6
通讯作者：
Akita, Munetaka
中科院分区：
文献类型：
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作者：
Hikichi, Shiro;Okuda, Hideho;Akita, Munetaka
过渡金属烷基过氧物种（M-OOR '; R'表示烷基）被假定为从工业过程到生物系统的各种氧化反应中的活性中间体。[1]特别是d0前过渡金属离子（第4 - 6族）的烷基过氧配合物，由于它们作为有机化合物的氧化剂（例如烯烃环氧化）的潜力而引起了人们的广泛关注。[2-5]后过渡金属的烷基过氧配合物由于其工业重要性和生物相关性而受到越来越多的关注。[6-8]镍由于其固有的氧化还原性质，被认为是促进各种有机转化反应的最有用的金属之一。镍二氧配合物化学的最新发展揭示了镍物种作为氧化剂的适用性。例如，双核镍（III）双（μ-氧代）化合物以与高价Fe和Cu的M2（μ-O）2物种类似的方式表现出脂肪族烃基物种的H-夺取。[9]此外，已经报道了几种镍二氧络合物[9b，10]和使用镍络合物的基于过氧化物的催化氧化反应[11]。由Suzuki及其同事报道的镍（II）烷基过氧络合物是通过金属支撑配体上的烷基自由基中心的O2氧化形成的，其本身是通过Ni 2（μ-O）2物种的H-提取产生的。[9a然而，镍烷基过氧络合物的结构和反应性仍有待研究，以提供对镍化合物和过氧化物之间的相互作用、所得镍过氧物种的固有反应性以及催化中间体的性质的洞察。本文报道了一种烷基过氧镍配合物[NiII（OOtBu）（TpiPr）]（1; TpiPr =氢化三（3，5-二-2-丙基吡唑基）硼酸盐）的分子结构和氧化活性。
Transition-metal alkylperoxo species (M-OOR’; R’denotes alkyl group) are postulated as reactive intermediates in various oxidation reactions ranging from industrial processes to biological systems.[1] The alkylperoxo complexes of d0 early transition-metal ions (groups 4–6), in particular, have attracted much attention, owing to their potential as oxygenating reagents for organic compounds (for example, olefin epoxidation).[2–5] Interest in the alkylperoxo complexes of late transition metals is also growing because of their industrial significance and biological relevance.[6–8] Nickel is recognized as one of the most useful metals in promoting various organic transformation reactions, owing its intrinsic redox properties. Recent developments in the chemistry of nickel dioxygen complexes have shed light on the applicability of nickel species as oxidizing agents. For example, dinuclear nickel (III) bis (μ-oxo) compounds exhibit H-abstraction of aliphatic hydrocarbyl species, in a similar fashion to the M2 (μ-O) 2 species of high-valent Fe and Cu.[9] Furthermore, several nickel dioxygen complexes [9b, 10] and peroxide-based catalytic oxidation reactions with nickel complexes [11] have been reported. An nickel (II) alkylperoxo complex, reported by Suzuki and coworkers, was formed by O2 oxygenation of the alkyl radical center on the metalsupporting ligand, which was itself generated through H-abstraction by the Ni2 (μ-O) 2 species.[9a, 12] However, the structure and reactivity of nickel alkylperoxo complexes remains to be studied, to afford an insight into the interaction between nickel compounds and peroxides, the intrinsic reactivity of the resulting nickel peroxo species, and the properties of catalytic intermediates. Herein we report the molecular structure and the oxidizing activity of a nickel (II) alkylperoxo complex,[NiII (OOtBu)(TpiPr)](1; TpiPr= hydrotris (3, 5-di-2-propylpyrazolyl) borate).