Roland Bryan K, Flora Ware H, Selby Hugh D, Armstrong Neal R, Zheng Zhiping
Department of Chemistry, University of Arizona, Tucson, Arizona 85721, USA.
J Am Chem Soc. 2006 May 24;128(20):6620-5. doi: 10.1021/ja057548w.
The reaction between the previously reported site-differentiated cluster solvate Re(6)(mu(3)-Se)(8)(PEt(3))(5)(MeCN)(2) (1) with pyridyl-based ditopic ligands 4,4'-trimethylenedipyridine (2), 1,2-bis(4-pyridyl)ethane (3), and (E)-1,2-bis(4-pyridyl)ethene (4) afforded cluster complexes of the general formula Re(6)(mu(3)-Se)(8)(PEt(3))(5)(L)(2) (5-7), where L represents one of the pyridyl-based ligands. Reacting these cluster complex-based ligands with the fully solvated cluster complex Re(6)(mu(3)-Se)(8)(MeCN)(6)(2) (8) produced dendritic arrays of the general formula {Re(6)(mu(3)-Se)(8)Re(6)(mu(3)-Se)(8)(PEt(3))(5)(L)}(SbF(6))(14) (9-11), each featuring six circumjacent Re(6)(mu(3)-Se)(8)(PEt(3))(5) units bridged to a Re(6)(mu(3)-Se)(8) core cluster by the pyridyl-based ligands. Electrochemical studies using a thin-layer electrochemical cell revealed cluster-based redox events in these cluster arrays. For 9 (L = 2), one reversible oxidation event corresponding to the removal of 7 electrons was observed, indicating noninteraction or extremely weak interactions between the clusters. For 10 (L = 3), two poorly resolved oxidation waves were found. For 11 (L = 4), two reversible oxidation events, corresponding respectively to the removal of 1 and 6 electrons, were observed with the 1-electron oxidation event occurring at a potential 150 mV more positive than the 6-electron oxidation. These electrochemical studies suggest intercluster coupling in 11 via through-bond electronic delocalization, which is consistent with electronic spectroscopic studies of this same molecule.
先前报道的位点分化簇溶剂化物Re(6)(μ(3)-Se)(8)(PEt(3))(5)(MeCN)(2)（1）与基于吡啶的双齿配体4,4'-三亚甲基二吡啶（2）、1,2-双（4-吡啶基）乙烷（3）和（E）-1,2-双（4-吡啶基）乙烯（4）反应，得到通式为Re(6)(μ(3)-Se)(8)(PEt(3))(5)(L)(2)（5 - 7）的簇配合物，其中L代表一种基于吡啶的配体。使这些基于簇配合物的配体与完全溶剂化的簇配合物Re(6)(μ(3)-Se)(8)(MeCN)(6)(2)（8）反应，生成通式为{Re(6)(μ(3)-Se)(8)Re(6)(μ(3)-Se)(8)(PEt(3))(5)(L)}(SbF(6))(14)（9 - 11）的树枝状阵列，每个阵列具有六个相邻的Re(6)(μ(3)-Se)(8)(PEt(3))(5)单元，通过基于吡啶的配体连接到一个Re(6)(μ(3)-Se)(8)核心簇上。使用薄层电化学池进行的电化学研究揭示了这些簇阵列中基于簇的氧化还原事件。对于9（L = 2），观察到一个对应于7个电子去除的可逆氧化事件，表明簇之间没有相互作用或相互作用极弱。对于10（L = 3），发现了两个分辨不清的氧化波。对于11（L = 4），观察到两个可逆氧化事件，分别对应于1个和6个电子的去除，1个电子的氧化事件发生的电位比6个电子的氧化事件正150 mV。这些电化学研究表明11中通过键间电子离域实现了簇间耦合，这与对该相同分子的电子光谱研究一致。
