New Metal−Organic Polygons Involving MM Quadruple Bonds: M<sub>8</sub>(O<sub>2</sub>C<sup>t</sup>Bu)<sub>4</sub>(μ-SC<sub>4</sub>H<sub>2</sub>-3,4-{CO<sub>2</sub>}<sub>2</sub>)<sub>6</sub> (M = Mo, W)
作者:Matthew J. Byrnes、Malcolm H. Chisholm、Nathan J. Patmore
DOI:10.1021/ic051516s
日期:2005.12.1
that intramolecular Mo2...O bonding is present, while the other thienylcarboxylate bridges merely serve to link these two [Mo2]...[Mo2] units together. The color of the compounds arises from intense M2 delta-to-thienyl pi transitions and, in THF, the complexes are redox-active and show four successive quasi-reversible oxidation waves. The [M8]+ radical cations, generated by one-electron oxidation with
M2(O2CtBu)4(其中M = Mo或W)与噻吩基-3,4-二羧酸(0.5-1.5当量)在甲苯中的反应通过一系列可检测的中间体进行,直至化合物M8(O2CtBu)4(mu -SC4H2-3,4- CO2} 2)6,其分离为对空气敏感的黄色(M = Mo)或红色(M = W)粉末,并在其质谱(MALDI)中显示母体分子离子。钼配合物的结构是通过单晶X射线晶体学测定的,并且显示出包含一个不寻常的M8多边形,该多边形涉及通过四个3,4-噻吩基羧酸酯基团连接的四个Mo2四重键合单元。该结构具有晶体学上规定的S4对称性,可以描述为高度扭曲的Mo2单元四面体或双蝶形,其中两个Mo2单元通过噻吩基二羧酸酯连接,从而存在分子内Mo2 ... O键,而其他噻吩基羧酸酯桥仅起将这两个[Mo2] ... [Mo2]单元连接在一起的作用。化合物的颜色来自强烈的M2δ到噻吩基pi跃迁,在THF中,络合物具