• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Is the mu-oxo-mu-peroxodiiron intermediate of a ribonucleotide reductase biomimetic a possible oxidant of epoxidation reactions?
【24h】

Is the mu-oxo-mu-peroxodiiron intermediate of a ribonucleotide reductase biomimetic a possible oxidant of epoxidation reactions?

机译：核糖核苷酸还原酶仿生品的mu-oxo-mu-peroxodiiron中间体是否可能是环氧化反应的氧化剂？

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Density functional calculations on a mu-oxo-mu-peroxodiiron complex (1) with a tetrapodal ligand BPP (BPP = N,N-bis(2-pyridylmethyl)-3-aminopropionate) are presented that is a biomimetic of the active site region of ribonucleotide reductase (RNR). We have studied all low-lying electronic states and show that it has close-lying broken-shell singlet and undecaplet (S=0, 5) ground states with essentially two sextet spin iron atoms. In strongly distorted electronic systems in which the two iron atoms have different spin states, the peroxo group moves considerably out of the plane of the mu-oxodiiron group due to orbital rearrangements. The calculated absorption spectra of (1,11)1 are in good agreement with experimental studies on biomimetics and RNR enzyme systems. Moreover, vibrational shifts in the spectrum due to O-18(2) substitution of the oxygen atoms in the peroxo group follow similar trends as experimental observations. To identify whether the mu-oxo-mu-1,2-peroxodiiron or the mu-oxo-mu-1,1-peroxodiiron complexes are able to epoxidize substrates, we studied the reactivity patterns versus propene. Generally, the reactions are stepwise via radical intermediates and proceed by two-state reactivity patterns on competing singlet and undecaplet spin state surfaces. However, both the mu-oxo-mu-1,2-peroxodiiron and mu-oxo-mu-1,1-peroxodiiron complex are sluggish oxidants with high epoxidation barriers. The epoxidation barriers for the mu-oxol-mu-1,1-peroxodiiron complex are significantly lower than the ones for the mu-oxo-mu-1,2-peroxodiiron complex but still are too high to be considered for catalytic properties. Thus, theory has ruled out two possible peroxodiiron catalysts as oxidants in RNR enzymes and biomimetics and the quest to find the actual oxidant in the enzyme mechanism continues.
机译：提出了具有四足配体BPP（BPP = N，N-双（2-吡啶基甲基）-3-氨基丙酸酯）的mu-oxo-mu-peroxodiiron配合物（1）的密度泛函计算，其是活性位点区域的仿生模型核糖核苷酸还原酶（RNR）的合成。我们已经研究了所有低位电子态，并表明它具有紧密的破碎壳单重态和去capletlet（S = 0，5）基态，其中基本有两个六重态的自旋铁原子。在两个铁原子具有不同自旋态的严重畸变的电子系统中，由于轨道重排，过氧基团显着移出mu-oxodiiron基团的平面。 （1,11）1的计算吸收光谱与仿生和RNR酶系统的实验研究非常吻合。此外，由于过氧基团中氧原子的O-18（2）取代，光谱中的振动位移遵循与实验观察结果相似的趋势。为了确定mu-oxo-mu-1,2-peroxodiiron或mu-oxo-mu-1,1-peroxodiiron配合物是否能够环氧化底物，我们研究了相对于丙烯的反应模式。通常，反应是通过自由基中间体逐步进行的，并且在竞争的单线态和非去甲壳态的自旋态表面上以两态反应性模式进行。但是，mu-oxo-mu-1,2-peroxodiiron和mu-oxo-mu-1,1-peroxodiiron配合物都是缓慢的氧化剂，具有高环氧化屏障。 mu-oxol-mu-1,1-peroxodiiron配合物的环氧化屏障明显低于mu-oxo-mu-1,2-peroxodiiron配合物的环氧化屏障，但仍然过高，无法考虑其催化性能。因此，理论排除了两种可能的过氧二铁催化剂作为RNR酶和仿生物中的氧化剂，并且继续寻找在酶机理中寻找实际氧化剂的探索。

著录项

相似文献

  • 外文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号