Metal-to-Ligand Ratio Controlled Assembly of Two Ni(II) Complexes: Structures, Luminescent and Electrochemical Properties
作者:Mei-Ling Cheng、Lu Liu、Lin Sun、Feng Tao、Meng-Na Qin、Qi Liu、Xiao-Yan Tang
DOI:10.1007/s10870-020-00854-1
日期:2021.6
Treatment of Ni(OAc)2·4 H2O with 3,4-pyrazoledicarboxylic acid (H3pdc) and imidazole (ImH) in different metal-to-ligand ratios afforded two dinuclear nickel(II) complexes, [Ni(Hpdc)(ImH)(H2O)2]2·4 H2O (1) and [Ni(Hpdc)(ImH)2(H2O)]2·2.5 H2O (2), which were characterized by elemental analysis (EA), IR spectra and X-ray diffraction analysis and thermogravimetric analysis (TGA). Both in 1 and 2, the dinickle unit [Ni2(µ2-Hdpc)2] with six-numbered Ni2N4 ring was formed by a pair of µ2-Hpdc2− ligands linked two Ni(II) ions in N,O-chelating and N‒N-bridging fashions. The dinuclear units in 1 and 2 were expanded to 2D layer structures though hydrogen-bonding interactions between coordination water molecules, ImH molecules and carboxylate oxygen atoms, whereas the lattice water molecules in 1 and 2 just embedded in the 2D layer through intermolecular hydrogen bonding interactions. Finally, the 2D sheets in 1 were further assembled to a 3D supramolecular architecture via intermolecular C–H⋯O hydrogen bond. Besides, the luminescent and electrochemical properties of two complexes have been reported. Two dinuclear nickel(II) complexes, [Ni(Hpdc)(ImH)(H2O)2]2·4 H2O (1) and [Ni(Hpdc)(ImH)2(H2O)]2·2.5 H2O (2), were obtained by assembling of a Ni(II) ion, 3,4-pyrazoledicarboxylic acid (H3pdc) and imidazole (ImH) in different metal-to-ligand ratios. In 1 and 2, the O(C, N)−H⋯O hydrogen bonds expanded the dinuclear complexes to 3D/2D supramolecular structures, respectively.
2中,由一对µ2-Hpdc2−配体以N,O螯合和N‒N桥联的方式连接两个Ni(II)离子,形成具有六元Ni2N4环的双镍单元[Ni2(µ2-Hdpc)2]。1和2中的双核单元通过配位水分子、ImH分子和羧酸氧原子之间的氢键相互作用扩展为二维