A 1D Mn-based coordination polymer with significant magnetocaloric effect

Abstract

A 1D Mn-containing coordination polymer (CP) has been prepared by the hydrothermal assembly of MnCl2·4H2O with Hcptpy and H2bdc (Hcptpy = 4-(4-carboxyphenyl)-2,2′:4′,4″-terpyridine, H2bdc = 1,4-benzenedicarboxylic acid), [Mn(cptpy)Cl(H2O)(DMF)]n (1), which is further structurally characterized by different methods including X-ray single-crystal diffraction, elemental analysis, infrared (IR) spectrum, thermogravimetric (TG) analysis, and powder X-ray diffraction (PXRD). Structural analysis indicates that the asymmetric skeleton of 1 consists of one Mn2+ ion, one cptpy– ligand, one Cl– anion, one coordinated H2O and one DMF. Each six-coordinated Mn2+ ion in 1 is alternately connected by carboxyl O atoms and pyridine N atoms of cptpy– ligands to present a 1D chain, which could be further stacked to produce a 3D supramolecular structure through hydrogen bonds and π···π stacking interactions. Magnetic results suggest that the presence of antiferromagnetic coupling interactions among Mn2+ ions in 1. Furthermore, 1 exhibits significant magnetocaloric effect (MCE) with the maximum –ΔSm value of 26.3 J·kg−1·K−1 at 2.0 K for an applied field of 70 kOe.