resonance (ENDOR). The ENDOR evidence was for a di-μ-oxo 17O hyperfine coupling of 12.8 ± 1.0 MHz. Narrow and highly resolved EPR features from dimers exchanged with H216O (I = 0) became broadened when the dimer was prepared by exchanging the cross bridging oxygens with H217O (I = 5/2). The EPR broadening due to 17O was quantitatively reproduced by a model where the dimer has two equivalent di-μ-oxo cross-bridging
Di-μ-oxo MnIII-MnIV 二聚体是绿色植物氧释放中心中耦合的混合价
锰的模型。使用最近报道的将
水氧交换到 di-μ-oxo 交叉桥中的方法(Tagore, R.; Chen, H.; Crabtree, RH; Brudvig, GWJ Am. Chem. Soc. 2006, 128, 9457−9465 ),我们已将 17O 并入 MnIII-MnIV 联
吡啶二聚体的 μ-氧交桥中,用于通过电子顺磁共振 (EPR) 和电子核双共振 (ENDOR) 研究氧电子-自旋超精细耦合。ENDOR 证据是针对 12.8 ± 1.0
MHz 的 di-μ-oxo 17O 超精细耦合。当通过与 H217O (I = 5/2) 交换交叉桥氧制备二聚体时,与 H216O (I = 0) 交换的二聚体的窄且高分辨率的 EPR 特征变宽。