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Landart A, Quesada-Moreno MM, Palacios MA, Li Y, Ozerov M, Krzystek J, Colacio E. Control of the geometry and anisotropy driven by the combination of steric and anion coordination effects in Co II complexes with N 6-tripodal ligands: the impact of the size of the ligand on the magnetization relaxation time. Dalton Trans 2024; 53:12876-12892. [PMID: 38716508 DOI: 10.1039/d4dt00622d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/07/2024]
Abstract
Four mononuclear CoII complexes of formula [Co(L)(SCN)2(CH3OH)0.5(H2O)0.5]·1.5H2O·0.75CH3OH (1), [Co(L1)Cl2]·H2O·2CH3CN (2), [Co(L1)(SCN)2]·1.5H2O·CH3OH (3) and [Co(L1)]ClO4·2CH3OH (4) were prepared from the N6-tripodal Schiff base ligands (S)P[N(Me)NC(H)2-Q]3 (L) and (S)P[N(Me)NC(H)1-ISOQ]3 (L1), where Q and ISOQ represent quinolyl and isoquinolyl moieties, respectively. In 1, the L ligand does not coordinate to the CoII ion in a tripodal manner but using a new N,N,S tridentate mode, which is due to the fact that the N6-tripodal coordination promotes a strong steric hindrance between the quinolyl moieties. However, L1 can coordinate to the CoII ions either in a tripodal manner using CoII salts with poorly coordinating anions to give 4 or in a bisbidentate fashion using CoII salt-containing medium to strongly coordinating anions to afford 2 and 3. In the case of L1, there is no steric hindrance between ISOQ moieties after coordination to the CoII ion. The CoII ion exhibits a distorted octahedral geometry for compounds 1-3, with the anions in cis positions for the former and in trans positions for the two latter compounds. Compound 4 shows an intermediate geometry between an octahedral and trigonal prism but closer to the latter one. DC magnetic properties, HFEPR and FIRMS measurements and ab initio calculations demonstrate that distorted octahedral complexes 1-3 exhibit easy-plane magnetic anisotropy (D > 0), whereas compound 4 shows large easy-axis magnetic anisotropy (D < 0). Comparative analysis of the magneto-structural data underlines the important role that is played not only by the coordination geometry but also the electronic effects in determining the anisotropy of the CoII ions. Compounds 2-3 show a field-induced slow relaxation of magnetization. Despite its large easy-axis magnetic anisotropy, compound 4 does not show significant slow relaxation (SMR) above 2 K under zero applied magnetic fields, but its magnetic dilution with ZnII triggers SMR at zero field. Finally, it is worth remarking that compounds 2-4 show smaller relaxation times than the analogous complexes with the tripodal ligand bearing in its arms pyridine instead of isoquinoline moieties, which is most likely due to the increase of the molecular size in the former one.
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Affiliation(s)
- Aritz Landart
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain.
| | - María Mar Quesada-Moreno
- Departamento de Química Física y Analítica, Facultad de Ciencias Experimentales, Universidad de Jaén, Campus Las Lagunillas, 23071 Jaén, Spain
| | - María A Palacios
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain.
| | - Yanling Li
- Sorbonne Université Institut Parisien de Chimie Moléculaire, CNRS UMR 8232 4 place Jussieu 75252, Paris cedex 5, France
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Enrique Colacio
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain.
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2
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Juráková J, Santana VT, Pavlik J, Moncoľ J, Nemec I, Clemente-León M, Kuppusamy SK, Ruben M, Čižmár E, Šalitroš I. Magnetic anisotropy and slow relaxation of magnetisation in double salts containing four- and six-coordinate cobalt(II) complex ions. Dalton Trans 2024; 53:12962-12972. [PMID: 39026489 DOI: 10.1039/d4dt01509f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Four novel Co(II) coordination compounds 1-4 of the general formula [Co(Ln)2][Co(NCY)4]·mCH3CN (where Ln are tridentate ligands L1 = 2,6-bis(1-hexyl-1H-benzimidazol-2-yl)pyridine for 1 and 2; L2 = 2,6-bis(1-octyl-1H-benzimidazol-2-yl)pyridine for 3; L3 = 2,6-bis(1-dodecyl-1H-benzimidazol-2-yl)pyridine for 4, Y = O for 1, 3, and 4 and Y = S for 2; m = 0 for 1 and 3, m = 0.5 for 2 and m = 2 for 4) were prepared and characterised. The molecular structures of all four compounds consist of the hexacoordinate complex cation [Co(Ln)2]2+ and tetracoordinate complex anion [Co(NCY)4]2-, with distorted octahedral and tetrahedral symmetry of coordination polyhedra, respectively. The electronic structures of all compounds feature an orbitally non-degenerate ground state well-separated from the lowest excited state, which allows the analysis of the magnetic anisotropy by the spin Hamiltonian model. ZFS parameters, derived from both CASSCF-NEVPT2 calculations and magnetic data analysis, indicate that tetrahedral anions [Co(NCY)4]2- exhibit small axial parameters |D| spanning the range of 2.2 to 7.7 cm-1, while octahedral cations [Co(Ln)2]2+ display significantly larger |D| parameters in the range of 37 to 95 cm-1. For 1-3, the Fourier-transform infrared magnetic spectroscopy (FIRMS) revealed a reasonable transmission with a magnetic absorption around the expected value for the ZFS accompanied by features allowing to identify phonon frequencies and simulate spin-phonon couplings. Dynamic magnetic investigations unveiled the field-induced slow relaxation of magnetisation, with maximal relaxation times (τ) of 92(2) μs for 2 at 2 K and BDC = 0.3 T. The temperature evolution of τ was analysed using a combination of Orbach, direct and Raman relaxations (Ueff = 8(1) K (5.6 cm-1)) or Orbach, direct and spin-phonon induced relaxations (Ueff = 10.3(9) K (7.2 cm-1)). The rest of the complexes, namely 1, 3, and 4 show field-induced slow relaxation of magnetisation with τ smaller than 16 μs.
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Affiliation(s)
- Jana Juráková
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia.
| | - Vinicius Tadeu Santana
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
| | - Ján Pavlik
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia.
| | - Ján Moncoľ
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia.
| | - Ivan Nemec
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic
| | - Miguel Clemente-León
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Catedrático José Beltrán 2, 46980 Paterna, Spain
| | - Senthil Kumar Kuppusamy
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Mario Ruben
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Erik Čižmár
- Institute of Physics, Faculty of Science, P.J. Šafárik University, Park Angelinum 9, 04154 Košice, Slovakia
| | - Ivan Šalitroš
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia.
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3
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Jabeur W, Korb M, Hamdi M, Holub M, Princík D, Zeleňák V, Sanchez-Coronilla A, Shalash M, Čižmár E, Naïli H. Structural, optical and magnetic properties of a new metal-organic Co II-based complex. RSC Adv 2024; 14:25048-25061. [PMID: 39135970 PMCID: PMC11317920 DOI: 10.1039/d4ra02149e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 06/03/2024] [Indexed: 08/15/2024] Open
Abstract
A mononuclear cobalt(ii) complex [C5H8N3]2[CoCl4(C5H7N3)2] (I) was synthesized and structurally characterized. Single crystal X-ray diffraction analysis indicates that monometallic Co(ii) ions acted as coordination nodes in a distorted octahedral geometry, giving rise to a supramolecular architecture. The latter is made up of a ½ unit form composed of an anionic element [Co0.5Cl2(C5H7N3)]- and one 2-amino-4-methylpyrimidinium cation [C5H8N3]+. The crystalline arrangement of this compound adopts the sandwich form where inorganic parts are sandwiched between the organic sheets following the [100] direction. More information regarding the structure hierarchy has been supplied based on Hirshfeld surface analysis; the X⋯H (X = N, Cl) interactions play a crucial role in stabilizing the self-assembly process of I, complemented by the intervention of π⋯π electrostatic interaction created between organic entities. Thermal analyses were carried out to study the thermal behavior process. Static magnetic measurements and ab initio calculations of compound I revealed the easy-axis anisotropy character of the central Co(ii) ion. Two-channel field-induced slow-magnetic relaxation was observed; the high-frequency channel is characterized by underbarrier relaxation with U eff = 16.5 cm-1, and the low-frequency channel involves a direct relaxation process affected by the phonon-bottleneck effect.
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Affiliation(s)
- Wiem Jabeur
- Laboratory Physico Chemistry of the Solid State, Department of Chemistry, Faculty of Sciences of Sfax, Sfax University POBOX 1171 3000 Sfax Tunisia
| | - Marcus Korb
- The University of Western Australia, School of Molecular Sciences 35 Stirling Highway, Crawley Perth Western Australia 6009 Australia
| | - Mohamed Hamdi
- Department of Chemistry, College of Sciences and Arts Turaif, Northern Border University Arar Saudi Arabia
| | - Mariia Holub
- Institute of Physics, Faculty of Science, P. J. Šafárik University in Košice SK-041 54 Košice Slovakia
| | - Dávid Princík
- Department of Inorganic Chemistry, Faculty of Science, P. J. Šafárik University Košice SK-041 54 Slovakia
| | - Vladimír Zeleňák
- Department of Inorganic Chemistry, Faculty of Science, P. J. Šafárik University Košice SK-041 54 Slovakia
| | | | - Marwan Shalash
- Department of Chemistry, College of Sciences and Arts Turaif, Northern Border University Arar Saudi Arabia
| | - Erik Čižmár
- Institute of Physics, Faculty of Science, P. J. Šafárik University in Košice SK-041 54 Košice Slovakia
| | - Houcine Naïli
- Laboratory Physico Chemistry of the Solid State, Department of Chemistry, Faculty of Sciences of Sfax, Sfax University POBOX 1171 3000 Sfax Tunisia
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4
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Zeng M, Ruan Z, Wu S, Tong M. Field-Induced Slow Magnetic Relaxation in Mononuclear Cobalt(II) Complexes Decorated by Macrocyclic Pentaaza Ligands. Molecules 2024; 29:2810. [PMID: 38930875 PMCID: PMC11206533 DOI: 10.3390/molecules29122810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 06/04/2024] [Accepted: 06/08/2024] [Indexed: 06/28/2024] Open
Abstract
Two cobalt(II) complexes [CoL1](OTf)2 (1, L1 = 6,6''-di(anilino)-4'-phenyl-2,2':6',2''-terpyridine) and [CoL2](OTf)2·MeOH (2, L2 = 6,6''-di(N,N-dimethylamino)-4'-phenyl-2,2':6',2''-terpyridine) were synthesized and characterized. Crystal structure analyses showed that the spin carries were coordinated by five N atoms from the neutral pentaaza ligands, forming distorted trigonal bipyramidal coordination environments. Ab initio calculations revealed large easy-axial anisotropy in complexes 1 and 2. Magnetic measurements suggest that complexes 1 and 2 are field-induced single-molecule magnets, whose relaxations are mainly predominated by Raman and direct processes.
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Affiliation(s)
| | | | - Siguo Wu
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, China; (M.Z.); (Z.R.); (M.T.)
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5
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Zabala-Lekuona A, Lopez de Pariza X, Díaz-Ortega IF, Cepeda J, Nojiri H, Gritsan NP, Dmitriev AA, López-Ortega A, Rodríguez-Diéguez A, Seco JM, Colacio E. From field-induced to zero-field SMMs associated with open/closed structures of bis(ZnDy) tetranuclear complexes: a combined magnetic, theoretical and optical study. Dalton Trans 2024; 53:7971-7984. [PMID: 38647324 DOI: 10.1039/d4dt00148f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
We have prepared a bis(compartmental) Mannich base ligand H4L (1,4,8,11-tetraaza-1,4,8,11-tetrakis(2-hydroxy-3-methoxy-5-methylbenzyl)cyclotetradecane) specifically designed to obtain bis(TMIILnIII) tetranuclear complexes (TM = transition metal). In this regard, we have succeeded in obtaining three new complexes of the formula [Zn2(μ-L)(μ-OAc)Dy2(NO3)2]·[Zn2(μ-L)(μ-OAc)Dy2(NO3)(OAc)]·4CHCl3·2MeOH (1) and [TM2(μ-H2L)2(μ-succinate)Ln2(NO3)2] (NO3)2·2H2O·6MeOH (TMII = Zn, LnIII = Dy (2); TMII = Co, LnIII = Dy (3)). Compound 1 contains two different bis(ZnDy) tetranuclear molecules that cocrystallize in the structure, in which acetato bridging ligands connect the ZnII and DyIII ions within each ZnDy subunit. This compound does not exhibit slow magnetic relaxation at zero field, but it is activated in the presence of an applied dc magnetic field and/or by Dy/Y magnetic dilution, showing two relaxation processes corresponding to each of the two different bis(ZnDy) units found in the structure. As revealed by the theoretical calculations, magnetic relaxation in 1 is single-ion in origin and takes place through the first excited state of each DyIII ion. When using the succinato dicarboxylate bridging ligand instead of acetate, compounds 2 and 3 were serendipitously formed, which have a closed structure with the succinate anion bridging two ZnDy subunits belonging to two different ligands. It should be noted that only compound 2 exhibits slow relaxation of magnetization in the absence of an external magnetic field. According to experimental and theoretical data, 2 relaxes through the second excited Kramers doublet (Ueff = 342 K). In contrast, 3 displays field-induced SMM behaviour (Ueff = 203 K). However, the Co/Zn diluted version of this compound 3Zn shows slow relaxation at zero field (Ueff = 347 K). Ab initio theoretical calculations clearly show that the weak ferromagnetic coupling between CoII and DyIII ions is at the origin of the lack of slow relaxation of this compound at zero field. Compound 2 and its diluted analogues 2Y and 3Zn show hysteresis loops at very low temperature, thus confirming their SMM behaviour. Finally, compounds 1 and 2 show DyIII based emission even at room temperature that, in the case of 2, allows us to extract the splitting of the ground 6H15/2 term, which matches reasonably well with theoretical calculations.
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Affiliation(s)
- Andoni Zabala-Lekuona
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco (UPV/EHU), 20018 Donostia-San Sebastián, Spain.
| | - Xabier Lopez de Pariza
- POLYMAT and Department of Polymers and Advanced Materials: Physics, Chemistry and Technology, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel de Lardizabal 3, Donostia-San Sebastián 20018, Spain
| | - Ismael F Díaz-Ortega
- Departamento de Química y Física-CIESOL, Universidad de Almería, Ctra. Sacramento s/n, 04120 Almería, Spain
- Institute for Materials Research, Tohoku University, Katahira, Sendai, 980-8577, Japan
| | - Javier Cepeda
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco (UPV/EHU), 20018 Donostia-San Sebastián, Spain.
| | - Hiroyuki Nojiri
- Institute for Materials Research, Tohoku University, Katahira, Sendai, 980-8577, Japan
| | - Nina P Gritsan
- Institute of Chemical Kinetics and Combustion, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Alexey A Dmitriev
- Institute of Chemical Kinetics and Combustion, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Alberto López-Ortega
- Departamento de Ciencias, Universidad Pública de Navarra, E-31006 Pamplona, Spain
- Institute for Advanced Materials and Mathematics (INAMAT2), Universidad Pública de Navarra, E-31006 Pamplona, Spain
- CIC nanoGUNE BRTA, Tolosa Hiribidea 76, Donostia-San Sebastian, 20018, Spain
| | - Antonio Rodríguez-Diéguez
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain.
| | - José M Seco
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco (UPV/EHU), 20018 Donostia-San Sebastián, Spain.
| | - Enrique Colacio
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain.
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Zabala-Lekuona A, Landart-Gereka A, Quesada-Moreno MM, Mota AJ, Díaz-Ortega IF, Nojiri H, Krzystek J, Seco JM, Colacio E. Zero-Field SMM Behavior Triggered by Magnetic Exchange Interactions and a Collinear Arrangement of Local Anisotropy Axes in a Linear Co 3II Complex. Inorg Chem 2023. [PMID: 37991724 DOI: 10.1021/acs.inorgchem.3c02817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
A new linear trinuclear Co(II)3 complex with a formula of [{Co(μ-L)}2Co] has been prepared by self-assembly of Co(II) ions and the N3O3-tripodal Schiff base ligand H3L, which is obtained from the condensation of 1,1,1-tris(aminomethyl)ethane and salicylaldehyde. Single X-ray diffraction shows that this compound is centrosymmetric with triple-phenolate bridging groups connecting neighboring Co(II) ions, leading to a paddle-wheel-like structure with a pseudo-C3 axis lying in the Co-Co-Co direction. The Co(II) ions at both ends of the Co(II)3 molecule exhibit distorted trigonal prismatic CoN3O3 geometry, whereas the Co(II) at the middle presents an elongated trigonal antiprismatic CoO6 geometry. The combined analysis of the magnetic data and theoretical calculations reveal strong easy-axis magnetic anisotropy for both types of Co(II) ions (|D| values higher than 115 cm-1) with the local anisotropic axes lying on the pseudo-C3 axis of the molecule. The magnetic exchange interaction between the middle and ends Co(II) ions, extracted by using either a Hamiltonian accounting for the isotropic magnetic coupling and ZFS or the Lines' model, was found to be medium to strong and antiferromagnetic in nature, whereas the interaction between the external Co(II) ions is weak antiferromagnetic. Interestingly, the compound exhibits slow relaxation of magnetization and open hysteresis at zero field and therefore SMM behavior. The significant magnetic exchange coupling found for [{Co(μ-L)}2Co] is mainly responsible for the quenching of QTM, which combined with the easy-axis local anisotropy of the CoII ions and the collinearity of their local anisotropy axes with the pseudo-C3 axis favors the observation of SMM behavior at zero field.
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Affiliation(s)
- Andoni Zabala-Lekuona
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco (UPV/EHU), 20018 Donostia-San Sebastián, Spain
| | - Aritz Landart-Gereka
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
| | - María Mar Quesada-Moreno
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
| | - Antonio J Mota
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
| | - Ismael F Díaz-Ortega
- Institute for Materials Research, Tohoku University, Katahira, Sendai 980-8577, Japan
| | - Hiroyuki Nojiri
- Institute for Materials Research, Tohoku University, Katahira, Sendai 980-8577, Japan
| | - Jurek Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - José M Seco
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco (UPV/EHU), 20018 Donostia-San Sebastián, Spain
| | - Enrique Colacio
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
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7
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Giraldo JN, Hrubý J, Vavrečková Š, Fellner OF, Havlíček L, Henry D, de Silva S, Herchel R, Bartoš M, Šalitroš I, Santana VT, Barbara P, Nemec I, Neugebauer P. Tetracoordinate Co(II) complexes with semi-coordination as stable single-ion magnets for deposition on graphene. Phys Chem Chem Phys 2023; 25:29516-29530. [PMID: 37901907 PMCID: PMC10631493 DOI: 10.1039/d3cp01426f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 10/03/2023] [Indexed: 10/31/2023]
Abstract
We present a theoretical and experimental study of two tetracoordinate Co(II)-based complexes with semi-coordination interactions, i.e., non-covalent interactions involving the central atom. We argue that such interactions enhance the thermal and structural stability of the compounds, making them appropriate for deposition on substrates, as demonstrated by their successful deposition on graphene. DC magnetometry and high-frequency electron spin resonance (HF-ESR) experiments revealed an axial magnetic anisotropy and weak intermolecular antiferromagnetic coupling in both compounds, supported by theoretical predictions from complete active space self-consistent field calculations complemented by N-electron valence state second-order perturbation theory (CASSCF-NEVPT2), and broken-symmetry density functional theory (BS-DFT). AC magnetometry demonstrated that the compounds are field-induced single-ion magnets (SIMs) at applied static magnetic fields, with slow relaxation of magnetization governed by a combination of quantum tunneling, Orbach, and direct relaxation mechanisms. The structural stability under ambient conditions and after deposition was confirmed by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Theoretical modeling by DFT of different configurations of these systems on graphene revealed n-type doping of graphene originating from electron transfer from the deposited molecules, confirmed by electrical transport measurements and Raman spectroscopy.
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Affiliation(s)
- Jorge Navarro Giraldo
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
| | - Jakub Hrubý
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
| | - Šárka Vavrečková
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
- Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2, 61669 Brno, Czech Republic
| | - Ondřej F Fellner
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 77147 Olomouc, Czech Republic
| | - Lubomír Havlíček
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
- Institute of Physics of Materials, Czech Academy of Sciences, Žižkova 22, 61662 Brno, Czech Republic
| | - DaVonne Henry
- Department of Physics, Georgetown University, Washington, DC, USA
| | - Shehan de Silva
- Department of Physics, Georgetown University, Washington, DC, USA
| | - Radovan Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 77147 Olomouc, Czech Republic
| | - Miroslav Bartoš
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
| | - Ivan Šalitroš
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia
| | - Vinicius T Santana
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
| | - Paola Barbara
- Department of Physics, Georgetown University, Washington, DC, USA
| | - Ivan Nemec
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 77147 Olomouc, Czech Republic
| | - Petr Neugebauer
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
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8
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Šedivý M, Santana V, Sojka A, Laguta O, Neugebauer P. MEPROS - Modular electron paramagnetic resonance operating software for multifunctional high-frequency EPR spectrometer. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 355:107556. [PMID: 37751649 DOI: 10.1016/j.jmr.2023.107556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 09/07/2023] [Accepted: 09/11/2023] [Indexed: 09/28/2023]
Abstract
We present a software solution developed in LabVIEW for a home-built High-Frequency Electron Paramagnetic Resonance (HF-EPR) spectrometer. A modular approach was applied to control the spectrometer subsystems and simplify the adaptation to hardware changes during the development. The solution implements measuring procedures for conventional Continuous Wave EPR (CW-EPR), Frequency-Swept EPR (FS-EPR), and Two-Dimensional EPR (2D-EPR) mapping, which are relevant in different cases. The software's automation capabilities were tested in several trial measurements to obtain CW-EPR spectra of Silicon Carbide doped by vanadium (SiC + V) at various temperatures and microwave frequencies, multi-frequency spectra via 2D-EPR mapping, and dense FS-EPR data of a lithium phthalocyanine crystal rotated in a magnetic field. Several prospective modifications of the software are discussed in the conclusion. A modular character allows the easy re-use of code portions in other experimental setups. The spectrometer and the software are currently deployed and utilized in a laboratory of EPR spectroscopy at Central European Institute of Technology (CEITEC) in Brno, and data obtained by it has been already used in a number of publications.
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Affiliation(s)
- Matúš Šedivý
- Magneto-Optical and THz Spectroscopy, Central European Institute of Technology (CEITEC), Brno University of Technology (BUT), Czech Republic; Department of Microelectronics, Faculty of Electrical Engineering and Communication, Brno University of Technology, Czech Republic.
| | - Vinicius Santana
- Magneto-Optical and THz Spectroscopy, Central European Institute of Technology (CEITEC), Brno University of Technology (BUT), Czech Republic
| | - Antonín Sojka
- Magneto-Optical and THz Spectroscopy, Central European Institute of Technology (CEITEC), Brno University of Technology (BUT), Czech Republic
| | - Oleksii Laguta
- Magneto-Optical and THz Spectroscopy, Central European Institute of Technology (CEITEC), Brno University of Technology (BUT), Czech Republic
| | - Petr Neugebauer
- Magneto-Optical and THz Spectroscopy, Central European Institute of Technology (CEITEC), Brno University of Technology (BUT), Czech Republic.
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9
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Kumar Sahu P, Kharel R, Shome S, Goswami S, Konar S. Understanding the unceasing evolution of Co(II) based single-ion magnets. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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10
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Sauza-de la Vega A, Pandharkar R, Stroscio GD, Sarkar A, Truhlar DG, Gagliardi L. Multiconfiguration Pair-Density Functional Theory for Chromium(IV) Molecular Qubits. JACS AU 2022; 2:2029-2037. [PMID: 36186551 PMCID: PMC9516709 DOI: 10.1021/jacsau.2c00306] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/19/2022] [Accepted: 08/19/2022] [Indexed: 05/30/2023]
Abstract
Pseudotetrahedral organometallic complexes containing chromium(IV) and aryl ligands have been experimentally identified as promising molecular qubit candidates. Here we present a computational protocol based on multiconfiguration pair-density functional theory for computing singlet-triplet gaps and zero-field splitting (ZFS) parameters in Cr(IV) aryl complexes. We find that two multireference methods, multistate complete active space second-order perturbation theory (MS-CASPT2) and hybrid multistate pair-density functional theory (HMS-PDFT), perform better than Kohn-Sham density functional theory for singlet-triplet gaps. Despite the very small values of the ZFS parameters, both multireference methods performed qualitatively well. MS-CASPT2 and HMS-PDFT performed particularly well for predicting the trend in the ratio of the rhombic and axial ZFS parameters, |E/D|. We have also investigated the dependence and sensitivity of the calculated ZFS parameters on the active space and the molecular geometry. The methodologies outlined here can guide future prediction of ZFS parameters in molecular qubit candidates.
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Affiliation(s)
- Arturo Sauza-de la Vega
- Department
of Chemistry, Pritzker School of Molecular Engineering, James Franck
Institute, Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Riddhish Pandharkar
- Department
of Chemistry, Pritzker School of Molecular Engineering, James Franck
Institute, Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
- Argonne
National Laboratory, Lemont, Illinois 60439, United States
| | - Gautam D. Stroscio
- Department
of Chemistry, Pritzker School of Molecular Engineering, James Franck
Institute, Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Arup Sarkar
- Department
of Chemistry, Pritzker School of Molecular Engineering, James Franck
Institute, Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Donald G. Truhlar
- Department
of Chemistry, Chemical Theory Center, and Minnesota Supercomputing
Institute, University of Minnesota, Minneapolis, Minnesota 55455−0431, United States
| | - Laura Gagliardi
- Department
of Chemistry, Pritzker School of Molecular Engineering, James Franck
Institute, Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
- Argonne
National Laboratory, Lemont, Illinois 60439, United States
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11
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The Role of the Bridge in Single-Ion Magnet Behaviour: Reinvestigation of Cobalt(II) Succinate and Fumarate Coordination Polymers with Nicotinamide. INORGANICS 2022. [DOI: 10.3390/inorganics10090128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Two previously synthesized cobalt(II) coordination polymers; {[Co(μ2-suc)(nia)2(H2O)2]·2H2O}n (suc = succinate(2−), nia = nicotinamide) and [Co(μ2-fum)(nia)2(H2O)2]n (fum = fumarate(2−)) were prepared and thoroughly characterized. Both complexes form 1D coordination chains by bonding of Co(nia)2(H2O)2 units through succinate or fumarate ligands while these chains are further linked through hydrogen bonds to 3D supramolecular networks. The intermolecular interactions of both complexes are quantified using Hirshfeld surface analysis and their infrared spectra, electronic spectra and static magnetic properties are confronted with DFT and state-of-the-art ab-initio calculations. Dynamic magnetic measurements show that both complexes exhibit single-ion magnet behaviour induced by a magnetic field. Since they possess very similar chemical structure, differing only in the rigidity of the bridge between the magnetic centres, this chemical feature is put into context with changes in their magnetic relaxation.
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12
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Juráková J, Šalitroš I. Co(II) single-ion magnets: synthesis, structure, and magnetic properties. MONATSHEFTE FUR CHEMIE 2022; 153:1001-1036. [PMID: 35615113 PMCID: PMC9123880 DOI: 10.1007/s00706-022-02920-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 04/25/2022] [Indexed: 01/01/2023]
Abstract
Magnetoactive coordination compounds exhibiting bi- or multistability between two or more magnetic stable states present an attractive example of molecular switches. Currently, the research is focused on molecular nanomagnets, especially single molecule magnets (SMMs), which are molecules, where the slow relaxation of the magnetization based on the purely molecular origin is observed. Contrary to ferromagnets, the magnetic bistability of SMMs does not require intermolecular interactions, which makes them particularly interesting in terms of application potential, especially in the high-density storage of data. This paper aims to introduce the readers into a basic understanding of SMM behaviour, and furthermore, it provides an overview of the attractive Co(II) SMMs with emphasis on the relation between structural features, magnetic anisotropy, and slow relaxation of magnetization in tetra-, penta-, and hexacoordinate complexes. Graphical abstract
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Affiliation(s)
- Jana Juráková
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
| | - Ivan Šalitroš
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava, 81237 Slovakia
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 771 46, Olomouc, Czech Republic
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13
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Huang YL, Zhong YJ, Ye HJ, Li YH, Kuang XM, Ouyang ZJ, Chen WB, Yang M, Dong W. Slow magnetic relaxation and spin crossover behavior in two mixed-valence Co( ii)/Co( iii) complexes. NEW J CHEM 2022. [DOI: 10.1039/d2nj03051a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two mixed-valence Co(ii)/Co(iii) complexes of [CoII(phen)3][CoIII(HATD)2]2·3DMA·3.5H2O (1) with field induced single-molecule magnet behavior, and [CoII(terpy)2][CoIII(HATD)2]2·4DMA·H2O (2) with a gradual thermal spin crossover (SCO).
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Affiliation(s)
- You-Lin Huang
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
| | - Yun-Jing Zhong
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
| | - Hua-Jian Ye
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
| | - You-Hong Li
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
| | - Xiao-Man Kuang
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
| | - Zhi-Jian Ouyang
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
| | - Wen-Bin Chen
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
| | - Meng Yang
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
| | - Wen Dong
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
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