Li Jia-Hui, Wang Xiu-Li, Song Ge, Lin Hong-Yan, Wang Xiang, Liu Guo-Cheng
College of Chemistry and Chemical Engineering, Professional Technology Innovation Center of Liaoning Province for Conversion Materials of Solar Cell, Bohai University, Jinzhou, 121013, P. R. China.
Dalton Trans. 2020 Jan 28;49(4):1265-1275. doi: 10.1039/c9dt04397g. Epub 2020 Jan 6.
Six new Anderson-type polyoxometalate (POM)-based metal-organic complexes (MOCs), namely, {HCu(HPCAP)[CrMo(OH)O]}·2HO (1), {Zn(PCAP)CrMo(OH)O}·4HO (2), {Zn(PCAP)CrMo(OH)O}·6HO (3), {Ni(PCAP)NiMo(OH)O}·8HO (4), {Cu(PCAP)AlMo(OH)O}·6HO (5), and {Co(HPCAP)AlMo(OH)O}[AlMo(OH)O]·6HO (6) (HPCAP = 3-(2-pyridinecarboxylic acid amido)pyridine), were constructed from diverse metal ions (Cu/Zn/Ni/Co), the HPCAP ligand and various Anderson-type POM anions under hydrothermal and solvothermal conditions and structurally characterized by single-crystal X-ray diffraction, IR spectroscopy, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). Crystal analysis shows that complex 1 has a 3D supramolecular structure based on the CrMo anions and the 1D metal-organic ribbon chains [Cu(HPCAP)] via hydrogen bonds. Complex 2 is a 2D supramolecular layer composed of two kinds of dinuclear metal clusters of [Zn(CrMo)] and [Zn(PCAP)]. Complexes 3-5 show similar 3D frameworks. In 3-5, [MMo] (M = Cr for 3, Ni for 4, and Al for 5) anions are bridged by M ions (M = Zn for 3, Ni for 4, and Cu for 5) to give a 1D M-MMo inorganic chain; the adjacent 1D inorganic chains are connected through two directions of [M(PACP)] rings to form a 3D framework. It should be noted that in complex 4, the NiMo anions are in situ generated from the Ni ion and MoO anions, which is rarely observed in POM-based MOCs. Complex 6 shows a 1D ladder-like supramolecular double chain, which is composed of 1D Co-AlMo inorganic chains, [Co(HPCAP)] dual-core rings and discrete AlMo polyanions interlinked by hydrogen bonding interactions. These structural diversities show that solvents play key roles in the construction of various architectures. All of the title complexes have excellent adsorption activities for the cationic dyes methylene blue (MB) and gentian violet (GV); in particular, complex 5 is capable of selectively adsorbing MB and GV from the mixtures of MB and MO and GV and MO, respectively. In addition, the electrochemical properties of complexes 1, 4, and 5 are also studied.
六种新型基于安德森型多金属氧酸盐（POM）的金属有机配合物（MOCs），即{ HCu(HPCAP)[CrMo(OH)O]}·2H₂O (1)、{ Zn(PCAP)CrMo(OH)O}·4H₂O (2)、{ Zn(PCAP)CrMo(OH)O}·6H₂O (3)、{ Ni(PCAP)NiMo(OH)O}·8H₂O (4)、{ Cu(PCAP)AlMo(OH)O}·6H₂O (5) 和 { Co(HPCAP)AlMo(OH)O}[AlMo(OH)O]·6H₂O (6)（HPCAP = 3-(2-吡啶甲酰胺基)吡啶），是在水热和溶剂热条件下由不同金属离子（Cu/Zn/Ni/Co）、HPCAP配体和各种安德森型POM阴离子构建而成，并通过单晶X射线衍射、红外光谱、粉末X射线衍射（PXRD）和热重分析（TGA）进行了结构表征。晶体分析表明，配合物1基于CrMo阴离子和通过氢键形成的一维金属有机带状链[Cu(HPCAP)]具有三维超分子结构。配合物2是由[Zn(CrMo)]和[Zn(PCAP)]两种双核金属簇组成的二维超分子层。配合物3 - 5显示出相似的三维骨架。在3 - 5中，[MMo]（3中M = Cr，4中M = Ni，5中M = Al）阴离子由M离子（3中M = Zn，4中M = Ni，5中M = Cu）桥连形成一维M - MMo无机链；相邻的一维无机链通过[M(PACP)]环的两个方向连接形成三维骨架。需要注意的是，在配合物4中，NiMo阴离子由Ni离子和MoO₄²⁻阴离子原位生成，这在基于POM的MOCs中很少见。配合物6显示出一维梯状超分子双链，它由一维Co - AlMo无机链、[Co(HPCAP)]双核环和通过氢键相互作用互连的离散AlMo多阴离子组成。这些结构多样性表明溶剂在各种结构的构建中起着关键作用。所有标题配合物对阳离子染料亚甲基蓝（MB）和龙胆紫（GV）都具有优异的吸附活性；特别是，配合物5能够分别从MB和MO以及GV和MO的混合物中选择性吸附MB和GV。此外，还研究了配合物1、4和5的电化学性质。
