Syntheses of Homochiral Multinuclear Ru Complexes Based on Oligomeric Bibenzimidazoles
摘要:
The homochiral multinuclear Ru complexes of the oligomeric bibenzimidazoles were synthesized using Lambda-[Ru(bpy)(2)(PY)(2)][(-)-O,O-dibenzoyl-L-tartrate]-12H(2)O as an enantiornerically pure building block. The complexations proceed with the retention of configuration to provide well-defined mononuclear, dinuclear, tetranuclear, and octanuclear Ru complexes successfully. The optical purity and the absolute configurations of the complexes were determined by NMR and circular dichroism spectrometry. The rare X-ray structure of a tetranuclear complex Lambda(4)[(Ru(bpy)(2))(4)(bis(BiBzlm))](PF6)(4) was resolved, The crystallographic analysis reveals that all the four Ru centers have A octahedral configurations, with a Ru-Ru separation of 5.509 angstrom across the bridging bibenzimidazole ligand, which maintains near coplanarity. The UV-vis spectroscopic and electrochemical properties of the homochiral multinuclear assemblies were studied, indicating weak electronic communications between the metal centers.
Efficient Synthesis and Characterization of Novel Bibenzimidazole Oligomers and Polymers as Potential Conjugated Chelating Ligands
作者:Jun Yin、Ronald L. Elsenbaumer
DOI:10.1021/jo051515h
日期:2005.11.1
synthesis of novel bibenzimidazole oligomers and polymers is reported here using methyl 2,2,2-trichloroacetimidate as a key starting material. The dimer, trimer, tetramer, and polymers of bibenzimidazole were synthesized as a new series of potential conjugated chelating ligands for metallopolymer studies. The polymers show a maximum absorption at around 400 nm. The optical band gap of the polymer was estimated