497844-58-3Relevant academic research and scientific papers
Syntheses, structures, and electronic interactions of dicyanamide/tricyanomethanide-bridged binuclear organometallic complexes
Zhang, Li-Yi,Shi, Lin-Xi,Chen, Zhong-Ning
, p. 633 - 640 (2003)
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](SbF6) (5) and [{Cp(PPh3)2Ru}2N(CN)2] (SbF6) (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)2](PF6)2 (5a) which exhibits a broad absorption band in the near-infrared region (centered at 1500 nm, ε = 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](CF3SO3) (9) and [{Cp(PPh3)2- Ru}2C(CN)3](SbF6) (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.
