Zhang Li-Yi, Shi Lin-Xi, Chen Zhong-Ning
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.
Inorg Chem. 2003 Jan 27;42(2):633-40. doi: 10.1021/ic025879t.
Dicyanamide-bound mononuclear compounds Cp(dppe)FeN(CN)2 (3) and Cp(PPh3)2RuN(CN)2 (4) were isolated in high yields by the reactions of Cp(dppe)FeCl (1) and Cp(PPh3)2RuCl (2), respectively, with excess sodium dicyanamide. Compounds 3 and 4 are excellent precursors for the design of dicyanamide-bridged binuclear complexes [Cp(dppe)Fe]2N(CN)2 (5) and [Cp(PPh3)2Ru]2N(CN)2 (6) by the incorporation with 1 and 2, respectively. Controlling oxidation of 5 with ferrocenium hexafluorophosphate afforded the mixed-valence compound [Cp(dppe)Fe]2N(CN)22 (5a) which exhibits a broad absorption band in the near-infrared region (centered at 1500 nm, epsilon = 750 cm-1 M-1) due to the intervalence charge transfer of Robin and Day class II mixed-valence system. Tricyanomethanide-bound mononuclear compounds Cp(dppe)FeC(CN)3 (7) and Cp(PPh3)2RuC(CN)3 (8) were prepared by the same methods as 3 and 4 using potassium tricyanomethanide as the starting material instead. The tricyanomethanide-bridged binuclear complexes [Cp(dppe)Fe]2C(CN)3 (9) and [Cp(PPh3)2- Ru]2C(CN)3 (10) were prepared by the reactions between 7 and 1 and between 8 and 2, respectively. Cyclic voltammograms of the dicyanamide/tricyanomethanide-bridged binuclear complexes showed stepwise reversible one-electron oxidation waves with the potential separation of the two redox couples in the range 0.14-0.25 V, indicating the demonstrably electronic communication is operative between the organometallic components through a dicyanamide/tricyanomethanide spacer with metal...metal distances more than 7.8 A. Furthermore, the electronic coupling transmitted by the tricyanomethanide is appreciably greater than that by the dicyanamide. The complexes 3-10 were characterized by elemental analysis, IR, UV-vis, 1H and 31P NMR, and ES-MS. The crystal structures of 3 and 5-9 were determined by X-ray crystallography.
通过分别使二氯（二亚磷酸二乙酯）合环戊二烯基铁（1）和二氯（三苯基膦）合环戊二烯基钌（2）与过量的双氰胺钠反应，以高产率分离得到了双氰胺键合的单核化合物二氯（二亚磷酸二乙酯）合环戊二烯基铁双氰胺（3）和二氯（三苯基膦）合环戊二烯基钌双氰胺（4）。化合物3和4是设计双氰胺桥连双核配合物[二氯（二亚磷酸二乙酯）合环戊二烯基铁]₂双氰胺（5）和[二氯（三苯基膦）合环戊二烯基钌]₂双氰胺（6）的优良前体，分别通过与1和2结合来制备。用六氟磷酸二茂铁控制5的氧化得到了混合价化合物[二氯（二亚磷酸二乙酯）合环戊二烯基铁]₂双氰胺₂（5a），由于罗宾和戴II类混合价体系的价间电荷转移，它在近红外区域呈现出一个宽吸收带（中心位于1500 nm，ε = 750 cm⁻¹ M⁻¹）。三氰基甲烷键合的单核化合物二氯（二亚磷酸二乙酯）合环戊二烯基铁三氰基甲烷（7）和二氯（三苯基膦）合环戊二烯基钌三氰基甲烷（8）通过与制备3和4相同的方法制备，只是使用三氰基甲烷钾作为起始原料。三氰基甲烷桥连的双核配合物[二氯（二亚磷酸二乙酯）合环戊二烯基铁]₂三氰基甲烷（9）和[二氯（三苯基膦）合环戊二烯基钌]₂三氰基甲烷（10）分别通过7与1以及8与2之间的反应制备。双氰胺/三氰基甲烷桥连双核配合物的循环伏安图显示出逐步可逆的单电子氧化波，两个氧化还原对的电位分离在0.14 - 0.25 V范围内，表明通过双氰胺/三氰基甲烷间隔基在金属……金属距离大于7.8 Å的有机金属组分之间明显存在电子通讯。此外，由三氰基甲烷传递的电子耦合明显大于由双氰胺传递的电子耦合。配合物3 - 10通过元素分析、红外光谱、紫外可见光谱、¹H和³¹P核磁共振以及电喷雾质谱进行了表征。3和5 - 9的晶体结构通过X射线晶体学确定。
