Reversible N-N coupling of NO Ligands on dinuclear ruthenium complexes and subsequent N2O evolution:: Relevance to nitric oxide reductase
Reversible N-N coupling of NO Ligands on dinuclear ruthenium complexes and subsequent N2O evolution:: Relevance to nitric oxide reductase
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DOI：
10.1021/ja0763504
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发表时间：
2007-11-21
影响因子：
15
通讯作者：
Onishi, Masayoshi
中科院分区：
文献类型：
--
作者：
Arikawa, Yasuhiro;Asayama, Taiki;Onishi, Masayoshi
发现了双核复合物上两个亚硝酰基配体前所未有的 N-N 偶联，这被认为是细菌 NO 还原酶 (NOR) 的关键步骤。 N-N 偶联配合物 (TpRu)(2)((sic)-CI)((sic)-pz){(sic)-k(2)-N(=O)-N(=O)} (2a) ((Tp = BH(pyrazol-1-yl) 3) 由 TpRuCl(2)(NO) (1) 与吡唑在 Et3N 存在下反应制备。好奇的 N-N 键距为X射线晶体学测定具有4-甲基吡唑桥的N-N偶联类似物的分子量为1.861(3)埃，并通过DFT计算证实2a的N-N键通过氧化断裂，得到[{TpRu(NO)}(2)((sic)-CI)((sic)-pz)](BF4)(2)(4a中心)。 dot(BF4)(2)，其在还原时重新形成 2a。有趣的是，随着 N2O 的演化，N-N 偶联复合物 2a 也转变为氧桥双核物种 Sa，这些发现将为有关 NOR 将 NO 还原为 N2O 的机制提供有价值的信息。
Unprecedented N-N coupling of two nitrosyl ligands on dinuclear complexes was discovered, which is proposed as a critical step in the bacterial NO reductase (NOR). The N-N coupled complex (TpRu)(2)((sic)-CI)((sic)-pz){(sic)-k(2)-N(=O)-N(=O)} (2a) ((Tp = BH(pyrazol-1-yl) 3) was prepared from the reaction of TpRuCl(2)(NO) (1) with pyrazole in the presence of Et3N. The curious N-N bond distance was X-ray crystallographically determined to be 1.861(3) angstrom for the N-N coupled analogue with a 4-methylpyrazolato bridge, and was confirmed by DFT calculation. The N-N bond of 2a was cleaved by oxidation to give [{TpRu(NO)}(2)((sic)-CI)((sic)-pz)](BF4)(2) (4a center dot(BF4)(2), which on reduction reformed 2a. It is interesting to note that the N-N coupled complex 2a was also transformed into the oxo-bridged dinuclear species Sa with the evolution of N2O. These findings would provide valuable information regarding the mechanism of NO reduction to N2O by NOR.