Di Francesco Gianna N, Gaillard Aleth, Ghiviriga Ion, Abboud Khalil A, Murray Leslie J
Department of Chemistry, Center for Catalysis, University of Florida , Gainesville, Florida 32611-7200, United States.
Inorg Chem. 2014 May 5;53(9):4647-54. doi: 10.1021/ic500333p. Epub 2014 Apr 18.
The synthesis and characterization of a family of tricopper clusters housed within a tris(β-diketimine) cyclophane ligand (H3L) that bear structural similarities to biological copper clusters are reported. In all complexes, each Cu atom is held within the N2-chelate of a single β-diketiminate arm. Reaction of L(3-) with CuCl affords an anionic complex containing a μ3-chloride donor in the central cavity, whereas there is no evidence for bromide incorporation in the product of the reaction of L(3-) with CuBr (Cu3L). Cu3L reacts with elemental sulfur to generate the corresponding air-stable mixed-valent (μ3-sulfido)tricopper complex, Cu3(μ3-S)L, which represents the first example of a sulfide-bridged copper cluster in which each metal center is both coordinatively unsaturated and held within a N-rich environment. The calculated LUMO is predominantly Cu-S π* in character and delocalized over all three metal centers, which is consistent with the isotropic ten-line absorption (g ∼ 2.095, A ∼ 33 G) observed at room temperature in EPR spectra of the one-electron chemically reduced complex, Cu3(μ3-S)L.
报道了一系列包含在三（β-二酮亚胺）环番配体（H3L）中的三铜簇合物的合成与表征，这些簇合物与生物铜簇在结构上具有相似性。在所有配合物中，每个铜原子都位于单个β-二酮亚胺臂的N2螯合配体中。L(3-)与CuCl反应得到一种阴离子配合物，其中心腔中含有一个μ3-氯供体，而L(3-)与CuBr反应的产物（Cu3L）中没有溴化物掺入的证据。Cu3L与元素硫反应生成相应的空气稳定的混合价（μ3-硫代）三铜配合物Cu3(μ3-S)L，这是第一个硫桥联铜簇的例子，其中每个金属中心都是配位不饱和的，并且处于富氮环境中。计算得到的最低未占分子轨道（LUMO）主要具有Cu-S π*特征，并且在所有三个金属中心上离域，这与在单电子化学还原配合物Cu3(μ3-S)L的电子顺磁共振（EPR）光谱中在室温下观察到的各向同性十线吸收（g ∼ 2.095，A ∼ 33 G）一致。
