title: First one-dimensional homochiral stairway-like Cu(II) chains: crystal structures, circular dichroism (CD) spectra, ferroelectricity and antiferromagnetic properties.
abstract: The reactions of enantiopure chiral ligands (+)/(−)-4,5-pinenepyridyl-2-pyrazine (LS/LR) with CuCl2·2H2O in CH3OH/CH2Cl2 solution led to the formations of one-dimensional homochiral enantiomeric pairs with the formula [Cu(LR/S)Cl2]n·2H2O (R-1 and S-1, the isomers containing the LR and LS ligands, respectively). The circular dichroism (CD) spectra verified their chiroptical activities and enantiomeric natures. Their structures have been determined by X-ray single-crystal analyses, showing stairway-like and mirror-symmetric features, which represent the first examples of homochiral metal complexes with stairway-like structures. The ferroelectric property measurement indicated that R-1 exhibits ferroelectricity with the remnant polarization (Pr) value of 0.02 μC cm−2 under an applied electric field of 6.1 kV cm−1 at room temperature. The magnetic investigation of R-1 showed a weak intrachain antiferromagnetic coupling between Cu(II)–Cu(II) ions mediated by pyrazine, which can be interpreted by a spin-polarization mechanism. All these results suggested that R-1 and S-1 are potential multifunctional molecule-based materials combining optical activity, ferroelectricity and magnetism within one molecule.
authors: Henan Provincial Key Laboratory of Surface and Interface Science, Zhengzhou University of Light Industry, Zhengzhou 450002, China. lixl@zzuli.edu.cn
authors: Xi-Li
authors: XL
authors: Li
authors: Chun-Lai
authors: CL
authors: Chen
authors: Li-Feng
authors: LF
authors: Han
authors: Cai-Ming
authors: CM
authors: Liu
authors: You
authors: Y
authors: Song
authors: Xiao-Gang
authors: XG
authors: Yang
authors: Shao-Ming
authors: SM
authors: Fang