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

Huarui Wang,Jianhua Qin

doi:10.3390/cryst12020278

Abstract

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), 4,4′-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 sdba2− ligands are ptptp2− ligands, respectively, and a 2D layer is constructed from sdba2− and ptptp2− 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 cpop3− ligands to give a 2D layer, which is penetrated by ptptp2− 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.

Highlights

Academic Editors: Ingo Dierking and Recently, extensive research on the design and synthesis of multi-core complexes has led to many practical and conceptual developments [1]
Ligands containing 1,2,4-triazole are considered to be interesting heterocyclic compounds because of their strong coordination ability to transition central metal ions and effective biological significance [6,7,8]. 1,2,4-triazole ligands are usually easy to coordinate with the metal ions by the N1, N2 atoms [9] to produce polynuclear complexes
The 1,2,4-triazole and its pyrazine derivative, 2-(5-{6-[5-(Pyrazin-2-yl)-1H-1,2,4-triazol-3-yl]pyridin-2-yl}-1H-1,2,4triazol-3-yl)pyrazine (H2 ptptp), have often been used as the linker based on the following considerations: (i) nitrogen atom chelation coordination; (ii) more potential coordination points and coordination modes; (iii) regardless of the conformation, H2 ptptp can provide potential tridentate and bidentate binding sites via rotation around the central C-C bond [13]

Summary

Introduction

Academic Editors: Ingo Dierking and Recently, extensive research on the design and synthesis of multi-core complexes has led to many practical and conceptual developments [1]. Many reports have shown that polynuclear complexes with relatively simple spatial structures have excellent properties, which may provide an opportunity for a better understanding of structure related properties [2,3]. The selective adsorption, catalysis and magnetism of multi-core complexes have proved to be very attractive [4,5]. Ligands containing 1,2,4-triazole are considered to be interesting heterocyclic compounds because of their strong coordination ability to transition central metal ions and effective biological significance [6,7,8]. 1,2,4-triazole ligands are usually easy to coordinate with the metal ions by the N1, N2 atoms [9] to produce polynuclear complexes. The 1,2,4-triazole and its pyrazine derivative, 2-(5-{6-[5-(Pyrazin-2-yl)-1H-1,2,4-triazol-3-yl]pyridin-2-yl}-1H-1,2,4triazol-3-yl)pyrazine (H2 ptptp), have often been used as the linker based on the following considerations: (i) nitrogen atom chelation coordination; (ii) more potential coordination points (bidentate, tridentate or tetradentate) and coordination modes; (iii) regardless of the conformation, H2 ptptp can provide potential tridentate and bidentate binding sites via rotation around the central C-C bond [13]

Methods

Results

Conclusion