135949 20240704095849.0 doi 10.3390/molecules26185626 sideral 125798 ART-2021-125798 eng Arauzo, Ana Universidad de Zaragoza (orcid)0000-0002-5999-341X Slow magnetic relaxation in {[CoCxAPy)] 2.15 H2O}n mof built from ladder-structured 2D layers with dimeric SMM rungs 2021 We present the magnetic properties of the metal-organic framework {[CoCxAPy]·2.15 H2O}n (Cx = bis(carboxypropyl)tetramethyldisiloxane; APy = 4, 4`-azopyridine) (1) that builds up from the stacking of 2D coordination polymers. The 2D-coordination polymer in the bc plane is formed by the adjacent bonding of [CoCxAPy] 1D two-leg ladders with Co dimer rungs, running parallel to the c-axis. The crystal packing of 2D layers shows the presence of infinite channels running along the c crystallographic axis, which accommodate the disordered solvate molecules. The Co(II) is six-coordinated in a distorted octahedral geometry, where the equatorial plane is occupied by four carboxylate oxygen atoms. Two nitrogen atoms from APy ligands are coordinated in apical positions. The single-ion magnetic anisotropy has been determined by low temperature EPR and magnetization measurements on an isostructural compound {[Zn0.8Co0.2CxAPy]·1.5 CH3OH}n (2). The results show that the Co(II) ion has orthorhombic anisotropy with the hard-axis direction in the C2V main axis, lying the easy axis in the distorted octahedron equatorial plane, as predicted by the ab initio calculations of the g-tensor. Magnetic and heat capacity properties at very low temperatures are rationalized within a S* = 1/2 magnetic dimer model with anisotropic antiferromagnetic interaction. The magnetic dimer exhibits slow relaxation of the magnetization (SMM) below 6 K in applied field, with a tlf ˜ 2 s direct process at low frequencies, and an Orbach process at higher frequencies with U/kB = 6.7 ± 0.5 K. This compound represents a singular SMM MOF built-up of Co-dimers with an anisotropic exchange interaction. Access copy available to the general public Unrestricted info:eu-repo/grantAgreement/ES/DGA/E12-20R info:eu-repo/grantAgreement/ES/MICINN/PGC2018-099024-B-I00 info:eu-repo/grantAgreement/ES/MINECO/MAT2017-83468-R info:eu-repo/semantics/openAccess by http://creativecommons.org/licenses/by/3.0/es/ 4.927 2021 CHEMISTRY, MULTIDISCIPLINARY 65 / 179 = 0.363 2021 Q2 T2 BIOCHEMISTRY & MOLECULAR BIOLOGY 114 / 297 = 0.384 2021 Q2 T2 0.705 2021 Analytical Chemistry 2021 Q1 Drug Discovery 2021 Q1 Pharmaceutical Science 2021 Q1 Molecular Medicine 2021 Q1 Organic Chemistry 2021 Q1 Medicine (miscellaneous) 2021 Q1 5.9 2021 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Bartolomé, Elena Luzón, Javier (orcid)0000-0002-9208-0807 Alonso, Pablo J. (orcid)0000-0003-3449-4929 Vlad, Angelica Cazacu, Maria Zaltariov, Mirela F. Shova, Sergiu Bartolomé, Juan Universidad de Zaragoza (orcid)0000-0002-6517-1236 Turta, Constantin 0 X Universidad de Zaragoza Serv.Gral. Apoyo Investigación Servicios. Div.Caract.Físi.Quí 2003 395 Universidad de Zaragoza Dpto. Física Materia Condensa. Área Física Materia Condensada 26, 18 (2021), 5626 [26 pp.] Molecules (Basel, Online) Molecules 1420-3049 2830892 http://zaguan.unizar.es/record/135949/files/texto_completo.pdf Versión publicada 2756760 http://zaguan.unizar.es/record/135949/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:135949 articulos driver 2024-07-04-07:58:55 ARTICLE