Novel Iron Porphyrin−Alkanethiolate Complex with Intramolecular NH···S Hydrogen Bond: Synthesis, Spectroscopy, and Reactivity
Novel Iron Porphyrin−Alkanethiolate Complex with Intramolecular NH···S Hydrogen Bond: Synthesis, Spectroscopy, and Reactivity
复制标题
DOI：
10.1021/ja992511v
复制
发表时间：
1999-11
影响因子：
15
通讯作者：
N. Suzuki;T. Higuchi;Y. Urano;K. Kikuchi;H. Uekusa;Y. Ohashi;T. Uchida;and Teizo Kitagawa;T. Nagano
中科院分区：
文献类型：
--
作者：
N. Suzuki;T. Higuchi;Y. Urano;K. Kikuchi;H. Uekusa;Y. Ohashi;T. Uchida;and Teizo Kitagawa;T. Nagano
在血红素酶中，细胞色素P450和NO合成酶（NOS）具有较强的氧化能力，它们的血红素铁具有硫酸盐配位，因此具有不同寻常的结构。因此，它们的结构-功能关系一直是人们关注的焦点。我们合成了第一个在催化氧化过程中保持硫酸盐配位的合成血红素硫酸盐（SR络合物2），并发现了几个显著的硫酸盐轴向配体效应。最近，通过对P450和NOS的晶体结构分析，发现P450和NOS的活性位点存在NH…S氢键。这样的键会显著影响血红素硫化物的化学性质。Ueyama和同事已经报道了含有NH…S氢键的血红素硫代酸酯的合成结构模型，但他们的论文没有包括NH…S氢键对血红素硫代酸酯催化活性影响的数据。为了研究NH…S氢键对催化氧化的影响，我们合成了一种具有分子内NH…S氢键的新型铁卟啉-烷硫酸盐配合物。配合物1通过在硫酸盐附近引入酰胺NH来形成NH…S氢键，而配合物2和3通过用n -甲基取代酰胺NH或在远离硫原子的位置引入乙酰胺来设计不形成NH…S氢键（图1）
Among heme enzymes, cytochrome P450 and NO synthase (NOS) have strong oxidizing ability and unusual structure, in that their heme irons have thiolate coordination. Consequently, much interest has been focused on their structure-function relationship. 1 We have synthesized the first synthetic heme thiolate (SR complex2) which retains thiolate coordination during catalytic oxidation and have found several remarkable thiolate axial ligand effects. 2Recently, the presence of an NH ‚‚‚S hydrogen bond in the active site of P450 and NOS has been suggested, based on the analysis of their crystal structure. 3 Such a bond should markedly affect the chemistry of the heme thiolate. Ueyama and co-workers have reported synthetic structural models of heme arenethiolate with an NH ‚‚‚S hydrogen bond, 4 but their paper did not include data about the influence of the NH ‚‚‚S hydrogen bond on the catalytic activity of the heme thiolate. We report here a novel iron porphyrin-alkanethiolate complex with an intramolecular NH ‚‚‚S hydrogen bond that we synthesized in order to examine the influence of the NH ‚‚‚S hydrogen bond on catalytic oxidation. Complex 1 was designed to form an NH ‚‚‚S hydrogen bond by introducing amide NH in the vicinity of the thiolate, while complexes 2 and 3 were designed not to form an NH ‚‚‚S hydrogen bond by replacing amide NH with N-methyl or by introducing acetamide in a position apart from the sulfur atom (Figure 1). 5