Synthesis, Structures, and Magnetic Properties of the Copper(II), Cobalt(II), and Manganese(II) Complexes with 9-Acridinecarboxylate and 4-Quinolinecarboxylate Ligands

To explore the relationships between the structures of ligands and their complexes, we have synthesized and
characterized a series of metal complexes with two structurally related ligands, 9-acridinecarboxylic acid (HL1) and
4-quinolinecarboxylate acid (HL2), [Cu2(μ2-OMe)2(L1)2(H2O)0.69]n 1, [Cu2(L1)4(CH3OH)2] 2, [Cu3(L1)6(CH3OH)6]·3H2O
3, [Mn3(L1)6(CH3OH)6]·3H2O 4, [Co3(L1)6(CH3OH)6]·3H2O 5, [Cu(L2)2]n 6, [Mn(L2)2(H2O)]n 7, and [Co(L2)2(H2O)]n 8.
1 is a three-dimensional (3D) polymer with an interpenetrating NbO type network showing one-dimensional (1D)
channels, whereas 2 and 3 take bi- and trinuclear structures, respectively, because of the differences in basicity
of the reaction systems in preparing the three complexes. 4 and 5 have trinuclear structures similar to that of 3.
In 1−5, ligand L1 performs different coordination modes with N,O-bridging in 1 and O,O‘-bridging in 2−5, and the
metal ions also show different coordination geometries:  square planar in 1, square pyramidal in 2, and octahedral
in 3−5. 6 has a two-dimensional structure containing (4,4) grids in which L2 adopts the N,O-bridging mode and the
CuII center takes square planar geometry. 7 and 8 are isostructural complexes showing 1D chain structures, with
L2 adopting the O,O-bridging mode. In addition, the intermolecular O−H···N hydrogen bonds and π−π stacking
interactions further extend the complexes (except 1 and 6), forming 3D structures. The magnetic properties of 2−7
have been investigated and discussed in detail.

为探究配体及其配合物的结构之间的关联，我们合成并表征了一系列基于两种结构相似配体的金属配合物，两种配体分别为9-吖啶羧酸（9-acridinecarboxylic acid，HL1）与4-喹啉羧酸（4-quinolinecarboxylate acid，HL2），对应的配合物依次为：[Cu₂(μ₂-OMe)₂(L1)₂(H₂O)₀.₆₉]ₙ 1、[Cu₂(L1)₄(CH₃OH)₂] 2、[Cu₃(L1)₆(CH₃OH)₆]·3H₂O 3、[Mn₃(L1)₆(CH₃OH)₆]·3H₂O 4、[Co₃(L1)₆(CH₃OH)₆]·3H₂O 5、[Cu(L2)₂]ₙ 6、[Mn(L2)₂(H₂O)]ₙ 7以及[Co(L2)₂(H₂O)]ₙ 8。
配合物1为具有互穿NbO型网络结构的三维（3D）聚合物，呈现一维（1D）孔道；而配合物2与3分别为双核与三核结构，这是由于制备这三种配合物时所用反应体系的碱度存在差异。配合物4与5具有与3相似的三核结构。
在配合物1~5中，配体L1展现出不同的配位模式：在配合物1中为N,O-桥联模式，在配合物2~5中为O,O'-桥联模式；同时金属离子也呈现不同的配位几何构型：配合物1中为平面正方形，配合物2中为四方锥构型，配合物3~5中为八面体构型。
配合物6为含有(4,4)网格的二维（2D）结构，其中配体L2采取N,O-桥联配位模式，Cu(II)中心为平面正方形配位构型。配合物7与8为同构配合物，呈现一维（1D）链状结构，配体L2采取O,O-桥联配位模式。
此外，除配合物1与6外，分子间O-H···N氢键与π-π堆积相互作用进一步拓展了这些配合物的结构，使其形成三维超分子结构。我们对配合物2~7的磁学性质进行了详细的研究与讨论。