Two Polynuclear Manganese(II) Complexes Based on Multidentate N‐Heterocyclic Aromatic Ligand and V‐Shaped Polycarboxylate Ligand: Synthesis, Crystal Structure Analysis and Magnetic Properties

The reaction of MnCl2, 2‐(5‐{6‐[5‐(Pyrazin‐2‐yl)‐1H‐1,2,4‐triazol‐3‐yl]pyridin‐2‐yl}‐1H‐ 1,2,4‐triazol‐3‐yl)pyrazine (H2ptptp), 4,4ʹ‐sulfonyldibenzoic acid (H2sdba) or 4‐(4‐carboxyphenoxy)phthalate acid (H3cpop) and [BMI]Br ionic liquids (BMI = 1‐butyl‐3‐methylimidazolium) gave rise to two complexes, {[Mn4(ptptp)2(sdba)2(H2O)2]∙2H2O}n (1) and {[Mn3(ptptp)(cpop)Br(H2O)2]∙2H2O}n (2). The compounds have been well characterized by elemental analysis, IR spectra, thermogravimetric analysis, as well as single‐crystal and powder X‐ray diffraction. The structure feature of 1 is that Mn(II) ions in the [Mn6(sdba)2] loops of V‐shaped sdba ligands are ptptp ligands, respectively, and a 2D layer is constructed from sdba and ptptp ligands. The adjacent 2D layers are connected by O–H⋯N hydrogen bonds to form a 3D supramolecular network. The neighbouring trinuclear Mn(II) clusters in 2 are linked by V‐shaped cpop ligands to give a 2D layer, which is penetrated by ptptp ligands to form self‐threading structure. The results of variable‐temperature magnetic studies have shown that the magnetic interactions between the Mn(II) ions in 1 and 2 are mainly due to antiferromagnetic coupling.