transfer. Rather a mechanism involving formation of a CuO2 intermediate prior to the loss of O2 in the rate-determining step is proposed. Calculations of similar inverse isotope effects, using stretching frequencies of CuO2 adducts generated from copper(I) complexes and O2, suggest that the intermediate has a superoxo structure. The use of 18O isotope effects to relate activated oxygen intermediates in enzymes
[Cu(II)(L)](OTf)2 和 [Cu(II)N3(L)](OTf) (L =
TEPA: tris(2-pyridylethyl)amine or
TMPA: tris(2-
吡啶基甲基)胺;OTf =
三氟甲磺酸盐)与超氧化物 (O2*-) 反应形成 [Cu(I)(L)](OTf) 和 O2。基于停流实验和竞争性氧 (18O) 动力学同位素对 (16,16)O2*- 和 (18,16)O2*- ((16,16) k/(18,16)k)。(16,16)k/(18,16)k 落在从 0.9836 +/- 0.0043 到 0.9886 +/- 0.0078 的窄范围内,对于具有不同配位几何形状和跨越 0.67 V 范围。结果与涉及决定速率的 O2*-结合或一步电子转移的机制不一致。而是提出了一种机制,涉及在速率确定步骤中损失 O2 之前形成
CuO2 中间体。使用由
铜 (I) 配合物和