- 期刊
過渡金屬超氧錯合物之結構研究
Structural Insights into Transition Metal Superoxide Complexes
摘要
在生物體內，氧氣與金屬蛋白酶共同扮演重要角色，從氧氣的運輸、儲存到有毒物質的降解，都具有不可忽視的地位。金屬蛋白酶與氧氣反應時，會產生涉及電子轉移的中間體，形成「金屬超氧錯合物（metal-superoxo）」或「金屬過氧錯合物（metal-peroxo）」。為了研究這些不穩定的中間體，化學家利用合成的過渡金屬錯合物來探討氧氣的活化與鍵結。在研究中，單晶繞射結構提供了最直接的結構資訊，並可透過得到的氧－氧鍵長來判斷雙氧配位基的電子組態是超氧或是過氧離子。然而，由於大多過渡金屬超氧錯合物不穩定性高，所以有結構鑑定的例子相對少，在這些例子中，雖然光譜或理論計算都支持超氧配位基的電子結構，但其X-ray單晶繞射數據顯示，氧－氧鍵長的範圍變化極大，我們將在此篇文章簡介這些過渡金屬超氧錯合物的例子，並且探討此氧－氧鍵長變化極大的現象。
並列摘要
In biology, O_2 and metalloproteins play crucial roles in processes such as O_2 transportation, storage, and the degradation of harmful species. During reactions involving metalloenzymes and O_2, intermediates such as metal-superoxo and metal-peroxo complexes, which are key to electron transfer, are often formed. To study these unstable intermediates, chemists have utilized synthetic model complexes to investigate O_2-activation chemistry. X-ray crystallography has been invaluable in providing direct structural evidence, including precise measurements of O-O bond distances, which are critical for assigning O_2 ligands to specific oxidation states, such as superoxo or peroxo forms. However, the inherent instability of most metal-superoxo complexes has resulted in only a limited number of structurally characterized examples. In such cases, electronic structure information is typically supported by spectroscopic and computational studies, though notable discrepancies in the reported O-O bond distances often remain. In this article, we review the reported metal-superoxo model complexes, examine the unusually wide range of O-O distances observed, and discuss the challenges and insights gained from this area of research.