Slow Magnetic Relaxation in {[CoCxAPy)] 2.15 H<sub>2</sub>O}<sub>n</sub> MOF Built from Ladder-Structured 2D Layers with Dimeric SMM Rungs
We present the magnetic properties of the metal-organic framework {[CoCxAPy]·2.15 H<sub>2</sub>O}<sub>n</sub> (Cx = bis(carboxypropyl)tetramethyldisiloxane; APy = 4,4`-azopyridine) (<b>1</b>) that builds up from the stacking of 2D coordination polymers. The 2D-coo...
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MDPI AG
2021-09-01
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| Series: | Molecules |
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| author | Ana Arauzo Elena Bartolomé Javier Luzón Pablo J. Alonso Angelica Vlad Maria Cazacu Mirela F. Zaltariov Sergiu Shova Juan Bartolomé Constantin Turta |
| author_facet | Ana Arauzo Elena Bartolomé Javier Luzón Pablo J. Alonso Angelica Vlad Maria Cazacu Mirela F. Zaltariov Sergiu Shova Juan Bartolomé Constantin Turta |
| author_sort | Ana Arauzo |
| collection | DOAJ |
| description | We present the magnetic properties of the metal-organic framework {[CoCxAPy]·2.15 H<sub>2</sub>O}<sub>n</sub> (Cx = bis(carboxypropyl)tetramethyldisiloxane; APy = 4,4`-azopyridine) (<b>1</b>) that builds up from the stacking of 2D coordination polymers. The 2D-coordination polymer in the <i>bc </i>plane is formed by the adjacent bonding of [CoCxAPy] 1D two-leg ladders with Co dimer rungs, running parallel to the <i>c</i>-axis. The crystal packing of 2D layers shows the presence of infinite channels running along the <i>c</i> 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 {[Zn<sub>0.8</sub>Co<sub>0.2</sub>CxAPy]·1.5 CH<sub>3</sub>OH}<sub>n</sub> (<b>2</b>). The results show that the Co(II) ion has orthorhombic anisotropy with the hard-axis direction in the C<sub>2V</sub> main axis, lying the easy axis in the distorted octahedron equatorial plane, as predicted by the <i>ab initio</i> calculations of the <b><i>g</i></b>-tensor. Magnetic and heat capacity properties at very low temperatures are rationalized within a <i>S</i>* = 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 t<sub>lf</sub> ≈ 2 s direct process at low frequencies, and an Orbach process at higher frequencies with <i>U</i>/k<sub>B</sub> = 6.7 ± 0.5 K. This compound represents a singular SMM MOF built-up of Co-dimers with an anisotropic exchange interaction. |
| first_indexed | 2024-03-10T07:23:40Z |
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| last_indexed | 2024-03-10T07:23:40Z |
| publishDate | 2021-09-01 |
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| spelling | doaj.art-e69c60fcf2e54f99b9625ab88eb9cb1c2023-11-22T14:25:58ZengMDPI AGMolecules1420-30492021-09-012618562610.3390/molecules26185626Slow Magnetic Relaxation in {[CoCxAPy)] 2.15 H<sub>2</sub>O}<sub>n</sub> MOF Built from Ladder-Structured 2D Layers with Dimeric SMM RungsAna Arauzo0Elena Bartolomé1Javier Luzón2Pablo J. Alonso3Angelica Vlad4Maria Cazacu5Mirela F. Zaltariov6Sergiu Shova7Juan Bartolomé8Constantin Turta9Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, SpainDepartment of Mechanical Engineering, Escola Universitària Salesiana de Sarrià (EUSS), Passeig de Sant Joan Bosco, 74, 08017 Barcelona, SpainInstituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, SpainInstituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, SpainDepartment of Inorganic Polymers, “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 700487 Iasi, RomaniaDepartment of Inorganic Polymers, “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 700487 Iasi, RomaniaDepartment of Inorganic Polymers, “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 700487 Iasi, RomaniaDepartment of Inorganic Polymers, “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 700487 Iasi, RomaniaInstituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, SpainDepartment of Inorganic Polymers, “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 700487 Iasi, RomaniaWe present the magnetic properties of the metal-organic framework {[CoCxAPy]·2.15 H<sub>2</sub>O}<sub>n</sub> (Cx = bis(carboxypropyl)tetramethyldisiloxane; APy = 4,4`-azopyridine) (<b>1</b>) that builds up from the stacking of 2D coordination polymers. The 2D-coordination polymer in the <i>bc </i>plane is formed by the adjacent bonding of [CoCxAPy] 1D two-leg ladders with Co dimer rungs, running parallel to the <i>c</i>-axis. The crystal packing of 2D layers shows the presence of infinite channels running along the <i>c</i> 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 {[Zn<sub>0.8</sub>Co<sub>0.2</sub>CxAPy]·1.5 CH<sub>3</sub>OH}<sub>n</sub> (<b>2</b>). The results show that the Co(II) ion has orthorhombic anisotropy with the hard-axis direction in the C<sub>2V</sub> main axis, lying the easy axis in the distorted octahedron equatorial plane, as predicted by the <i>ab initio</i> calculations of the <b><i>g</i></b>-tensor. Magnetic and heat capacity properties at very low temperatures are rationalized within a <i>S</i>* = 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 t<sub>lf</sub> ≈ 2 s direct process at low frequencies, and an Orbach process at higher frequencies with <i>U</i>/k<sub>B</sub> = 6.7 ± 0.5 K. This compound represents a singular SMM MOF built-up of Co-dimers with an anisotropic exchange interaction.https://www.mdpi.com/1420-3049/26/18/5626MOFsingle molecule magnetslow magnetic relaxation2D coordination polymeranisotropic exchangemagnetic dimer |
| spellingShingle | Ana Arauzo Elena Bartolomé Javier Luzón Pablo J. Alonso Angelica Vlad Maria Cazacu Mirela F. Zaltariov Sergiu Shova Juan Bartolomé Constantin Turta Slow Magnetic Relaxation in {[CoCxAPy)] 2.15 H<sub>2</sub>O}<sub>n</sub> MOF Built from Ladder-Structured 2D Layers with Dimeric SMM Rungs Molecules MOF single molecule magnet slow magnetic relaxation 2D coordination polymer anisotropic exchange magnetic dimer |
| title | Slow Magnetic Relaxation in {[CoCxAPy)] 2.15 H<sub>2</sub>O}<sub>n</sub> MOF Built from Ladder-Structured 2D Layers with Dimeric SMM Rungs |
| title_full | Slow Magnetic Relaxation in {[CoCxAPy)] 2.15 H<sub>2</sub>O}<sub>n</sub> MOF Built from Ladder-Structured 2D Layers with Dimeric SMM Rungs |
| title_fullStr | Slow Magnetic Relaxation in {[CoCxAPy)] 2.15 H<sub>2</sub>O}<sub>n</sub> MOF Built from Ladder-Structured 2D Layers with Dimeric SMM Rungs |
| title_full_unstemmed | Slow Magnetic Relaxation in {[CoCxAPy)] 2.15 H<sub>2</sub>O}<sub>n</sub> MOF Built from Ladder-Structured 2D Layers with Dimeric SMM Rungs |
| title_short | Slow Magnetic Relaxation in {[CoCxAPy)] 2.15 H<sub>2</sub>O}<sub>n</sub> MOF Built from Ladder-Structured 2D Layers with Dimeric SMM Rungs |
| title_sort | slow magnetic relaxation in cocxapy 2 15 h sub 2 sub o sub n sub mof built from ladder structured 2d layers with dimeric smm rungs |
| topic | MOF single molecule magnet slow magnetic relaxation 2D coordination polymer anisotropic exchange magnetic dimer |
| url | https://www.mdpi.com/1420-3049/26/18/5626 |
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