A magnetic and conductive study on a stable defective extended cobalt atom chain
Wen-Zhen Wang1, Yang Wu, Rayyat H Ismayilov
1School of Chemistry and Chemical Engineering, Xi'an Shiyou University, 18 Dian-zi-er Road, Xi'an, Shaanxi, P R China. wzwang@xsyu.edu.cn.
Abstract:
Two pentacobalt(II) EMACs were synthesized. A pyrazine-modulated tripyridyldiamine resulted in an EMAC with fully delocalized Co-Co bonds along molecules. From a pyrazine- and naphthyridine-containing ligand, a defective cobalt linear EMAC with an 8-coordinated cobalt(II) in the center was obtained for the first time. An electrochemistry study on the defective pentacobalt chain compound showed redox peaks at E1/2 = -1.00, +0.76, and +0.98 V (versus EAg/AgCl), indicating that it is quite stable and very resistant to both oxidation and reduction. Research on magnetism revealed that the fully delocalized Co EMAC is a spin mixture, and the defective cobalt EMAC showed a high-spin mononuclear cobalt(II) behaviour with a magnetic moment of 2.63 μB per molecule at room temperature. Measurement on molecular electric conductance by STM bj showed a single-molecular resistance of 15.4 (± 3.1) MΩ for defective and 12.3 (± 2.6) MΩ for delocalized pentacobalt complexes.
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