Coordination polymers containing a pyrazole-based ligand and 4,4′-bipyridine as a spacer: enhancing the family of nonzero-dimensional compounds featuring single-ion magnetic behavior

• Published in: Inorganic chemistry communications Vol. 121; p. 108201
• Main Authors: Soares, Iuri C., Junior, Henrique C.S., de Almeida, Patrícia S.V.B., Alves, Odivaldo C., Soriano, Stéphane, Ferreira, Glaucio B., Guedes, Guilherme P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2020
• Subjects: Coordination polymers; Crystal structures; Ferromagnetic chain; Magnetic properties; Pyrazole; Single-ion magnet; Single-ion magnet; Coordination polymers; Crystal structures; Ferromagnetic chain; Pyrazole; Magnetic properties
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2020.108201

[Display omitted] •Two 1D-coordination polymers containing a pyrazole-based ligand and 4,4′-bipy.•Predominant ferromagnetic interactions in the copper-based compound.•ZFS effects are important for magnetic behavior of cobalt(II) polymer.•CASSCF calculations determined the sign of the axial component of the ZFS.•Slow relaxation of the magnetization and a single-ion magnet behavior. Two coordination polymers with molecular formula 1∞[M(L)2(4,4′-bipy)(H2O)2], where M stands for CoII (1) or CuII, (2), and L = 5-amino-1-phenyl-1H-pyrazole-4-carboxylate ligand were obtained by slow solvent diffusion and characterized by spectroscopic techniques, single crystal and powder X-ray diffraction, magnetic measurements, and DFT calculations. Magnetic studies carried out for complex 1 showed the key role played by the zero-field splitting and the experimental fit parameters were correlated to CASSCF calculations. Moreover, AC magnetic measurements for 1 revealed a field-induced slow relaxation of the magnetization and a single-ion magnet behavior. For the copper-containing polymer, two kinds of magnetic interactions were observed in the magnetic data and confirmed by using broken-symmetry DFT calculations: (i) ferromagnetic interchain coupling mediated by the hydrogen-bonds and (ii) antiferromagnetic intrachain interaction through the 4,4′-bipy ligand.