Tris[3-(2-pyridyl)pyrazolyl]hydroborate 鐵化合物的合成與反應性的研究與探討

Tris[3-(2-pyridyl)pyrazolyl]hydroborate 配位基在活化小分子的金屬催化酶的例子中是非常重要的。但是KTp(py)在文獻中，並沒有KTp(py)以鐵二價為中心的模型化合物的例子。這是很令人好奇的因為在自然界中常常看到，以鐵為活性中心活化小分子的例子。因此本文採用鐵為中心的化合物[Tp(py)FeCl]。利用外懸臂模擬金屬催化酶的氨基酸殘基或是形成氫鍵以穩定化合物的存在。本文進一步的去測試Tp(py)FeCl的反應性，並去模擬金屬催化酶的模型化合物，如Nitrite Reductase的亞硝酸鹽金屬螯合物，與模擬Methane monooxygenase系統中的中間產物Tp(py)FeOH，或是模擬 Cytochrome P450與Catechol Dioxygenases的高價金屬氧化態的前驅物[Tp(py)FeN3](1) 的晶體結構以及IR光譜。在其它反應性方面也成功的得到[Tp(py)FeCN](2)的IR光譜,以及NMR的光譜圖譜。

關鍵字

鐵；酵素；催化

並列摘要

Trispyrazolylborate (Tp−) type compound is a very important ligand set for small molecules activation the metalloenzyme mimicking system. Tris[3-(2-pyridyl)pyrazolyl]-hydroborate (Tp(py)−) is a new type of Tp- ligand set which provides additional pyridine coordination site in 3-postion to explore some new coordination behavior for metal complexes. It is worth mentioning that there are no example of iron complexes containing Tp(py)− ligand. Therefore, we focus on the synthesis and reactivity study of Tp(py)FeCl compound for the outer pyridine arm may mimic the amino acid residue around metalloenzyme active center. The Tp(py)FeCl complex represents as the first example of iron complex containing Tp(py)− ligand and the dangling pyridine arm can be used to mimic the second sphere coordination environment of the iron containing enzyme active site. The coordinated chloride ligand were replaced by N3− and CN− in DMF solution to give Tp(py)FeN3 (1) and Tp(py)FeCN (2) respectively. The structure of complex 1 was characterized by X-ray crystallography showing a five-coordination Fe(II) center similar to that of Tp(py)FeCl. Complexes 1 and 2 were all examined by UV-vis and Infrared spectroscopies. Complex 2 also can be characterized by NMR spectroscopy to confirm the low spin electron configuration and diamagnetism.