Brown Eric C, York John T, Antholine William E, Ruiz Eliseo, Alvarez Santiago, Tolman William B
Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, USA.
J Am Chem Soc. 2005 Oct 12;127(40):13752-3. doi: 10.1021/ja053971t.
By treating Cu(I) complexes of neutral, bidentate N-donor ligands with S8, clusters with novel delocalized mixed-valence [Cu3(mu-S)2]3+ cores have been isolated. X-ray crystal structures and UV-vis and resonance Raman spectral features of these clusters reveal similarities to the tetracopper-sulfide "CuZ" site in nitrous oxide reductase. A delocalized S = 1 ground state for the mixed-valent CuIIICu2II cores is supported by the observation of high symmetry in the X-ray structures and 10-line hyperfine features arising from coupling to three equivalent Cu ions in EPR spectra obtained at room temperature (shown) and 10 K. The delocalization we observe contrasts with the localization reported previously for a [Cu3(mu-O)2]3+ analogue (Root, D. E.; Henson, M. J.; Machonkin, T.; Mukherjee, P.; Stack, T. D. P.; Solomon, E. I. J. Am. Chem. Soc. 1998, 120, 4982), which we rationalized through DFT calculations.
通过用S8处理中性双齿氮供体配体的Cu(I)配合物，已分离出具有新型离域混合价[Cu3(μ-S)2]3+核心的簇合物。这些簇合物的X射线晶体结构以及紫外可见光谱和共振拉曼光谱特征显示出与一氧化二氮还原酶中的四铜硫化物“CuZ”位点相似。X射线结构中的高对称性以及在室温（如图所示）和10 K下获得的电子顺磁共振光谱中与三个等效铜离子耦合产生的10线超精细特征，支持了混合价CuIIICu2II核心的离域S = 1基态。我们观察到的离域现象与之前报道的[Cu3(μ-O)2]3+类似物的局域化情况形成对比（Root, D. E.; Henson, M. J.; Machonkin, T.; Mukherjee, P.; Stack, T. D. P.; Solomon, E. I. J. Am. Chem. Soc. 1998, 120, 4982），我们通过密度泛函理论计算对此进行了合理化解释。
