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Kormschikov ID, Polovkova MA, Kirakosyan GA, Martynov AG, Gorbunova YG, Tsivadze AY. Magnetic Anisotropy of Homo- and Heteronuclear Terbium(III) and Dysprosium(III) Trisphthalocyaninates Derived from Paramagnetic 1H-NMR Investigation. Molecules 2024; 29:510. [PMID: 38276588 PMCID: PMC11154240 DOI: 10.3390/molecules29020510] [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: 12/23/2023] [Revised: 01/13/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024] Open
Abstract
1H-NMR spectroscopy of lanthanide complexes is a powerful tool for deriving spectral-structural correlations, which provide a clear link between the symmetry of the coordination environment of paramagnetic metal centers and their magnetic properties. In this work, we have first synthesized a series of homo- (M = M* = Dy) and heteronuclear (M ≠ M* = Dy/Y and Dy/Tb) triple-decker complexes [(BuO)8Pc]M[(BuO)8Pc]M*[(15C5)4Pc], where BuO- and 15C5- are, respectively, butoxy and 15-crown-5 substituents on phthalocyanine (Pc) ligands. We provide an algorithmic approach to assigning the 1H-NMR spectra of these complexes and extracting the axial component of the magnetic susceptibility tensor, χax. We show how this term is related to the nature of the lanthanide ion and the shape of its coordination polyhedron, providing an experimental basis for further theoretical interpretation of the revealed correlations.
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Affiliation(s)
- Ilya D. Kormschikov
- Faculty of Chemistry, Lomonosov Moscow State University, GSP-1, Leninskie Gory, 119991 Moscow, Russia;
| | - Marina A. Polovkova
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr., 31, Building 4, 119071 Moscow, Russia; (M.A.P.); (G.A.K.); (Y.G.G.); (A.Y.T.)
| | - Gayane A. Kirakosyan
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr., 31, Building 4, 119071 Moscow, Russia; (M.A.P.); (G.A.K.); (Y.G.G.); (A.Y.T.)
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky pr., 31, 119991 Moscow, Russia
| | - Alexander G. Martynov
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr., 31, Building 4, 119071 Moscow, Russia; (M.A.P.); (G.A.K.); (Y.G.G.); (A.Y.T.)
| | - Yulia G. Gorbunova
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr., 31, Building 4, 119071 Moscow, Russia; (M.A.P.); (G.A.K.); (Y.G.G.); (A.Y.T.)
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky pr., 31, 119991 Moscow, Russia
| | - Aslan Yu. Tsivadze
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr., 31, Building 4, 119071 Moscow, Russia; (M.A.P.); (G.A.K.); (Y.G.G.); (A.Y.T.)
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky pr., 31, 119991 Moscow, Russia
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2
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Martynov AG, Birin KP, Kirakosyan GA, Gorbunova YG, Tsivadze AY. Site-Selective Solvation-Induced Conformational Switching of Heteroleptic Heteronuclear Tb(III) and Y(III) Trisphthalocyaninates for the Control of Their Magnetic Anisotropy. Molecules 2023; 28:4474. [PMID: 37298954 PMCID: PMC10254442 DOI: 10.3390/molecules28114474] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/24/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023] Open
Abstract
In the present work, we report the synthesis of isomeric heteronuclear terbium(III) and yttrium(III) triple-decker phthalocyaninates [(BuO)8Pc]M[(BuO)8Pc]M*[(15C5)4Pc] (M = Tb, M* = Y or M = Y, M* = Tb, [(BuO)8Pc]2--octa-n-butoxyphthalocyaninato-ligand, [(15C5)4Pc]2--tetra-15-crown-5-phthalocyaninato-ligand). We show that these complexes undergo solvation-induced switching: the conformers in which both metal centers are in square-antiprismatic environments are stabilized in toluene, whereas in dichloromethane, the metal centers M and M* are in distorted prismatic and antiprismatic environments, respectively. This conclusion follows from the detailed analysis of lanthanide-induced shifts in 1H NMR spectra, which makes it possible to extract the axial component of the magnetic susceptibility tensor χaxTb and to show that this term is particularly sensitive to conformational switching when terbium(III) ion is placed in the switchable "M" site. This result provides a new tool for controlling the magnetic properties of lanthanide complexes with phthalocyanine ligands.
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Affiliation(s)
- Alexander G. Martynov
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr., 31, Building 4, 119071 Moscow, Russia; (K.P.B.); (G.A.K.); (Y.G.G.); (A.Y.T.)
| | - Kirill P. Birin
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr., 31, Building 4, 119071 Moscow, Russia; (K.P.B.); (G.A.K.); (Y.G.G.); (A.Y.T.)
| | - Gayane A. Kirakosyan
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr., 31, Building 4, 119071 Moscow, Russia; (K.P.B.); (G.A.K.); (Y.G.G.); (A.Y.T.)
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky pr., 31, 119991 Moscow, Russia
| | - Yulia G. Gorbunova
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr., 31, Building 4, 119071 Moscow, Russia; (K.P.B.); (G.A.K.); (Y.G.G.); (A.Y.T.)
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky pr., 31, 119991 Moscow, Russia
| | - Aslan Yu. Tsivadze
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr., 31, Building 4, 119071 Moscow, Russia; (K.P.B.); (G.A.K.); (Y.G.G.); (A.Y.T.)
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky pr., 31, 119991 Moscow, Russia
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3
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Castellanos E, Demir S. Linear, Electron-Rich, Homoleptic Rare Earth Metallocene and Its Redox Activity. Inorg Chem 2023; 62:2095-2104. [PMID: 36689470 DOI: 10.1021/acs.inorgchem.2c03735] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The first homoleptic sandwich complex of dibenzocyclooctatetraene (dbCOT), representing a large cyclooctatetraene (COT) ligand with two fused benzene moieties, for any metal was accessed through salt metathesis of YCl3 with K2dbCOT in the presence of 2.2.2-cryptand. Single-crystal X-ray diffraction analysis on red-brown [K(crypt-222)][Y(dbCOT)2], 1, revealed a remarkably linear anionic yttrocene complex featuring a centroid-yttrium-centroid angle of 180.0°. The anionic moiety adopts a pseudo D2d geometry, where the carbon atoms of the central COT ring exhibit a staggered geometry. In total, 36 π-electrons are stored on both dbCOT anions, rendering it the largest isolated sandwich complex containing only fused aromatic rings. The solution-state structure of 1 was probed through a series of techniques involving cyclic voltammetry, UV-vis, and 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, including 89Y NMR. The density functional theory (DFT) and natural bond orbital (NBO) analysis uncovered an ionic bonding interaction between the (dbCOT)2- ligands and YIII ion. NICS calculations support the experimentally observed aromatic character of 1, despite the deviation from planarity found in the dbCOT moieties. The cyclic voltammograms allude to the accessibility of a radical oxidation state, dbCOT3-•, based on a quasi-reversible feature. Excitingly, the chemical one-electron reduction of 1 through exposure to potassium graphite yielded a paramagnetic molecule, which was detected by electron paramagnetic resonance (EPR) techniques. Notably, this EPR spectrum is the first one for any sandwich complex containing a COT radical. Remarkably, 1 is thermally stable, and its isolation may provide access to mono- and multinuclear complexes comprising heavier metals with applications in small-molecule activation, single-molecule magnetism, and molecular nanowires.
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Affiliation(s)
- Ernesto Castellanos
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Selvan Demir
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
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Pramanik K, Jagličić Z, Herchel R, Brandão P, Jana NC, Panja A. Combined experimental and theoretical studies on a series of mononuclear Ln III single-molecule magnets: dramatic influence of remote substitution on the magnetic dynamics in Dy analogues. Dalton Trans 2023; 52:1241-1256. [PMID: 36606746 DOI: 10.1039/d2dt03354b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A series of LnIII complexes of general formula [Ln(H2L1)2(NO3)2(H2O)](NO3) (1-5) [Ln = Dy (1), Tb (2) Ho (3), Er (4), and Yb (5)] and an analogous DyIII complex with ligand H2L2, [Dy(H2L2)2(NO3)3(H2O)](NO3) (6), where H2L1 and H2L2 stand for (E)-2-[(2-hydroxyphenyl)iminomethyl]-6-methoxy-4-methylphenol and (E)-2-[(2-hydroxy-5-methylphenyl)iminomethyl]-6-methoxy-4-methylphenol, respectively, have been synthesized and magneto-structurally characterized. All these complexes are isostructural and isomorphous, in which the zwitterionic form of the ligands predominantly coordinate the metal centers. The magnetic study revealed that complex 3 displays negligible SMM behaviour, while 1 and 6 are zero field SMMs, the performance of which can largely be improved in the presence of an applied dc field by lowering under barrier relaxation processes, and finally 2, 4, and 5 are field-induced SMMs. The most remarkable observation in the present study is the dramatically-enhanced SMM performance in 6 compared to 1, achieved by only a remote methyl substitution at the ligand framework to increase the intermolecular separation. Although SINGLE_ANISO ab initio calculations for 1 and 6 are very similar, the POLY_ANISO module revealed weak dipolar interactions in both the compounds but significant antiferromagnetic interaction in 1, thereby justifying the experimental fact. The present work discloses that even a small substitution such as a methyl group can adequately increase the intermolecular separation, leading to several-fold enhanced effective energy barrier.
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Affiliation(s)
- Kuheli Pramanik
- Department of Chemistry, Gokhale Memorial Girls' College, 1/1 Harish Mukherjee Road, Kolkata 700020, India. .,Department of Chemistry, Panskura Banamali College, Panskura RS, WB 721152, India
| | - Zvonko Jagličić
- Institute of Mathematics, Physics and Mechanics & Faculty of Civil and Geodetic Engineering, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia
| | - Radovan Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 77146 Olomouc, Czech Republic
| | - Paula Brandão
- Department of Chemistry, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Narayan Ch Jana
- Department of Chemistry, Panskura Banamali College, Panskura RS, WB 721152, India
| | - Anangamohan Panja
- Department of Chemistry, Gokhale Memorial Girls' College, 1/1 Harish Mukherjee Road, Kolkata 700020, India. .,Department of Chemistry, Panskura Banamali College, Panskura RS, WB 721152, India
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5
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Santana FS, Perfetti M, Briganti M, Sacco F, Poneti G, Ravera E, Soares JF, Sessoli R. A dysprosium single molecule magnet outperforming current pseudocontact shift agents. Chem Sci 2022; 13:5860-5871. [PMID: 35685802 PMCID: PMC9132026 DOI: 10.1039/d2sc01619b] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 04/26/2022] [Indexed: 12/19/2022] Open
Abstract
A common criterion for designing performant single molecule magnets and pseudocontact shift tags is a large magnetic anisotropy. In this article we present a dysprosium complex chemically designed to exhibit strong easy-axis type magnetic anisotropy that is preserved in dichloromethane solution at room temperature. Our detailed theoretical and experimental studies on the magnetic properties allowed explaining several features typical of highly performant SMMs. Moreover, the NMR characterization shows remarkably large chemical shifts, outperforming the current state-of-the art PCS tags.
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Affiliation(s)
- Francielli S Santana
- Departamento de Química, Universidade Federal do Paraná, Centro Politécnico 81530-900 Curitiba PR Brazil
| | - Mauro Perfetti
- Department of Chemistry "U. Schiff", University of Florence Via della Lastruccia 3-13, Sesto Fiorentino 50019 Italy
- Research Unit Firenze, INSTM I-50019 Sesto Fiorentino Firenze Italy
| | - Matteo Briganti
- Departamento de Química, Universidade Federal do Paraná, Centro Politécnico 81530-900 Curitiba PR Brazil
- Department of Chemistry "U. Schiff", University of Florence Via della Lastruccia 3-13, Sesto Fiorentino 50019 Italy
| | - Francesca Sacco
- Department of Chemistry "U. Schiff", University of Florence Via della Lastruccia 3-13, Sesto Fiorentino 50019 Italy
- Magnetic Resonance Center (CERM), University of Florence Via Luigi Sacconi 6, Sesto Fiorentino 50019 Italy
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine Via Luigi Sacconi 6, Sesto Fiorentino 50019 Italy
| | - Giordano Poneti
- Instituto de Química, Universidade Federal do Rio de Janeiro, Centro de Tecnologia - Cidade Universitária Avenida Athos da Silveira Ramos, 149 21941-909 Rio de Janeiro Brazil
| | - Enrico Ravera
- Department of Chemistry "U. Schiff", University of Florence Via della Lastruccia 3-13, Sesto Fiorentino 50019 Italy
- Magnetic Resonance Center (CERM), University of Florence Via Luigi Sacconi 6, Sesto Fiorentino 50019 Italy
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine Via Luigi Sacconi 6, Sesto Fiorentino 50019 Italy
| | - Jaísa F Soares
- Departamento de Química, Universidade Federal do Paraná, Centro Politécnico 81530-900 Curitiba PR Brazil
| | - Roberta Sessoli
- Department of Chemistry "U. Schiff", University of Florence Via della Lastruccia 3-13, Sesto Fiorentino 50019 Italy
- Research Unit Firenze, INSTM I-50019 Sesto Fiorentino Firenze Italy
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6
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Lang L, Ravera E, Parigi G, Luchinat C, Neese F. Theoretical analysis of the long-distance limit of NMR chemical shieldings. J Chem Phys 2022; 156:154115. [PMID: 35459319 DOI: 10.1063/5.0088162] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
After some years of controversy, it was recently demonstrated how to obtain the correct long-distance limit [point-dipole approximation (PDA)] of pseudo-contact nuclear magnetic resonance chemical shifts from rigorous first-principles quantum mechanics [Lang et al., J. Phys. Chem. Lett. 11, 8735 (2020)]. This result confirmed the classical Kurland-McGarvey theory. In the present contribution, we elaborate on these results. In particular, we provide a detailed derivation of the PDA both from the Van den Heuvel-Soncini equation for the chemical shielding tensor and from a spin Hamiltonian approximation. Furthermore, we discuss in detail the PDA within the approximate density functional theory and Hartree-Fock theories. In our previous work, we assumed a relatively crude effective nuclear charge approximation for the spin-orbit coupling operator. Here, we overcome this assumption by demonstrating that the derivation is also possible within the fully relativistic Dirac equation and even without the assumption of a specific form for the Hamiltonian. Crucial ingredients for the general derivation are a Hamiltonian that respects gauge invariance, the multipolar gauge, and functional derivatives of the Hamiltonian, where it is possible to identify the first functional derivative with the electron number current density operator. The present work forms an important foundation for future extensions of the Kurland-McGarvey theory beyond the PDA, including induced magnetic quadrupole and higher moments to describe the magnetic hyperfine field.
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Affiliation(s)
- Lucas Lang
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Enrico Ravera
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via Sacconi 6, Sesto Fiorentino 50019, Italy
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via Sacconi 6, Sesto Fiorentino 50019, Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via Sacconi 6, Sesto Fiorentino 50019, Italy
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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Pavlov AA, Novikov VV, Nikovskiy IA, Melnikova EK, Nelyubina YV, Aleshin DY. Analysis of reduced paramagnetic shifts as an effective tool in NMR spectroscopy. Phys Chem Chem Phys 2022; 24:1167-1173. [PMID: 34931208 DOI: 10.1039/d1cp04648a] [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
A recently introduced concept of reduced paramagnetic shifts (RPS) in NMR spectroscopy is applied here to a series of paramagnetic complexes with different metal ions, such as iron(II), iron(III) and cobalt(II), in different coordination environments of N-donor ligands, including a unique trigonal-prismatic geometry that is behind some record single-molecule magnet behaviours. A simple, almost visual analysis of the chemical shifts as a function of temperature, which is at the core of this approach, allows for a correct signal assignment and evaluation of the anisotropy of the magnetic susceptibility, the key indicator of a good single molecule magnet, that often cannot be done using traditional techniques rooted in quantum chemistry and NMR spectroscopy. The proposed approach thus emerged as a powerful alternative in deciphering the NMR spectra of paramagnetic compounds for applications in data processing and storage, magnetic resonance imaging and structural biology.
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Affiliation(s)
- Alexander A Pavlov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991, Moscow, Russia. .,Moscow Institute of Physics and Technology, Institutskiy per., 9, Dolgoprudny, Moscow Region, 141701, Russia
| | - Valentin V Novikov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991, Moscow, Russia. .,National Research University Higher School of Economics, Miasnitskaya Str. 20, Moscow 101000, Russia
| | - Igor A Nikovskiy
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991, Moscow, Russia.
| | - Elizaveta K Melnikova
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991, Moscow, Russia. .,Lomonosov Moscow State University, Leninskie Gory, Moscow, 119991, Russia
| | - Yulia V Nelyubina
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991, Moscow, Russia. .,Moscow Institute of Physics and Technology, Institutskiy per., 9, Dolgoprudny, Moscow Region, 141701, Russia
| | - Dmitry Y Aleshin
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991, Moscow, Russia.
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8
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Yang H, Liu SS, Meng YS, Zhang YQ, Pu L, Wang X, Lin S. Four mononuclear dysprosium complexes with neutral Schiff-base ligands: syntheses, crystal structures and slow magnetic relaxation behavior. Dalton Trans 2021; 51:1415-1422. [PMID: 34951422 DOI: 10.1039/d1dt03701c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Four mononuclear 9-coordinate Dy-based complexes, [Dy(HL1)2(NO3)3(CH3OH)] (1Dy), [Dy(HL2)2(NO3)3(H2O)] (2Dy), [Dy(HL3)3(NO3)3]·CH3CN (3Dy), and [Dy(HL4)3(NO3)3] (4Dy), have been constructed by neutral Schiff-base ligands (1-[N-(4-R)aminomethylidene-2(1H)-naphthalenone, R = -Cl (HL1), -NO2 (HL2), -OCH3 (HL3), -I (HL4)). By tuning the terminal substituent group of HL ligands, the number of HL ligands coordinated to the central Dy3+ ion unexpectedly varies from 2 to 3, and the local symmetry around the Dy3+ ion reduces from D3h to Cs. Magnetic measurements reveal that 2Dy can display single-ion magnet (SIM) behavior in zero dc field, while 1Dy, 3Dy and 4Dy show field-induced slow magnetic relaxation. Ab initio calculations were employed to elucidate magnetic anisotropy in the complexes, including g-tensors, averaged transition magnetic moments and magnetic easy axes. The difference in magnetic behaviors of the four complexes can be ascribed to the terminal substituent effect of neutral Schiff-base ligands.
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Affiliation(s)
- Hui Yang
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Shan-Shan Liu
- Beijing Key Laboratory of Fuels Cleaning and Advanced Catalytic Emission Reduction Technology, College of New Materials and Chemical Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617, P. R. China.
| | - Yin-Shan Meng
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, 2 Linggong Rd., Dalian 116024, P.R. China
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Lin Pu
- Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China
| | - Xincheng Wang
- Beijing Key Laboratory of Fuels Cleaning and Advanced Catalytic Emission Reduction Technology, College of New Materials and Chemical Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617, P. R. China.
| | - Shijing Lin
- Beijing Key Laboratory of Fuels Cleaning and Advanced Catalytic Emission Reduction Technology, College of New Materials and Chemical Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617, P. R. China.
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9
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Novikov VV, Nelyubina YV. Modern physical methods for the molecular design of single-molecule magnets. RUSSIAN CHEMICAL REVIEWS 2021. [DOI: 10.1070/rcr5002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Abstract
Many paramagnetic metal complexes have emerged as unique magnetic materials (single-molecule magnets), which behave as conventional magnets at the single-molecule level, thereby making it possible to use them in modern devices for data storage and processing. The rational design of these complexes, however, requires a deep understanding of the physical laws behind a single-molecule magnet behaviour, the mechanisms of magnetic relaxation that determines the magnetic properties and the relationship of these properties with the structure of single-molecule magnets. This review focuses on the physical methods providing such understanding, including different versions and various combinations of magnetometry, electron paramagnetic and nuclear magnetic resonance spectroscopy, optical spectroscopy and X-ray diffraction. Many of these methods are traditionally used to determine the composition and structure of new chemical compounds. However, they are rarely applied to study molecular magnetism.
The bibliography includes 224 references.
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Abstract
Nuclear Magnetic Resonance is particularly sensitive to the electronic structure of matter and is thus a powerful tool to characterize in-depth the magnetic properties of a system. NMR is indeed increasingly recognized as an ideal tool to add precious structural information for the development of Single Ion Magnets, small complexes that are recently gaining much popularity due to their quantum computing and spintronics applications. In this review, we recall the theoretical principles of paramagnetic NMR, with particular attention to lanthanoids, and we give an overview of the recent advances in this field.
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11
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Ravera E, Gigli L, Suturina EA, Calderone V, Fragai M, Parigi G, Luchinat C. A High-Resolution View of the Coordination Environment in a Paramagnetic Metalloprotein from its Magnetic Properties. Angew Chem Int Ed Engl 2021; 60:14960-14966. [PMID: 33595173 DOI: 10.1002/anie.202101149] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Indexed: 12/13/2022]
Abstract
Metalloproteins constitute a significant fraction of the proteome of all organisms and their characterization is critical for both basic sciences and biomedical applications. A large portion of metalloproteins bind paramagnetic metal ions, and paramagnetic NMR spectroscopy has been widely used in their structural characterization. However, the signals of nuclei in the immediate vicinity of the metal center are often broadened beyond detection. In this work, we show that it is possible to determine the coordination environment of the paramagnetic metal in the protein at a resolution inaccessible to other techniques. Taking the structure of a diamagnetic analogue as a starting point, a geometry optimization is carried out by fitting the pseudocontact shifts obtained from first principles quantum chemical calculations to the experimental ones.
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Affiliation(s)
- Enrico Ravera
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Lucia Gigli
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | | | - Vito Calderone
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Marco Fragai
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
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12
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Ravera E, Gigli L, Suturina EA, Calderone V, Fragai M, Parigi G, Luchinat C. A High‐Resolution View of the Coordination Environment in a Paramagnetic Metalloprotein from its Magnetic Properties. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202101149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Enrico Ravera
- Magnetic Resonance Center (CERM) University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff” University of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Lucia Gigli
- Magnetic Resonance Center (CERM) University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff” University of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | | | - Vito Calderone
- Magnetic Resonance Center (CERM) University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff” University of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Marco Fragai
- Magnetic Resonance Center (CERM) University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff” University of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM) University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff” University of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM) University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff” University of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
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13
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Gorbunova YG, Martynov AG, Birin KP, Tsivadze AY. NMR Spectroscopy—A Versatile Tool for Studying the Structure and Magnetic Properties of Paramagnetic Lanthanide Complexes in Solutions (Review). RUSS J INORG CHEM+ 2021. [DOI: 10.1134/s0036023621020091] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Pankratova YA, Nelyubina YV, Novikov VV, Pavlov AA. High-Spin Cobalt(II) Complex with Record-Breaking Anisotropy of the Magnetic Susceptibility According to Paramagnetic NMR Spectroscopy Data. RUSS J COORD CHEM+ 2021. [DOI: 10.1134/s1070328420120052] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract
The tetrahedral cobalt(II) complex [CoL2](HNEt3)2 (I), where L is 1,2-bis(methanesulfonamido)benzene, exhibiting the properties of a single-molecule magnet is synthesized and characterized. The electronic structure parameters of complex I are determined by paramagnetic NMR spectroscopy. They completely reproduce the results of less available methods of studying single-molecule magnets. The value of axial anisotropy of the magnetic susceptibility estimated for complex I (Δχax = 34.5 × 10–32 m3 at 20°C) is record-breaking among all transition metal complexes studied by the NMR method, which provides wide possibilities for the use of complex I as a paramagnetic label for structural biology or as a contrast agent and even a temperature sensor for medical diagnostics. The data obtained indicate the advantages of paramagnetic NMR spectroscopy as a method of investigation of the magnetic properties and electronic structures of highly anisotropic transition metal complexes, which are precursors of many functional materials.
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15
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Ravera E, Gigli L, Czarniecki B, Lang L, Kümmerle R, Parigi G, Piccioli M, Neese F, Luchinat C. A Quantum Chemistry View on Two Archetypical Paramagnetic Pentacoordinate Nickel(II) Complexes Offers a Fresh Look on Their NMR Spectra. Inorg Chem 2021; 60:2068-2075. [PMID: 33478214 PMCID: PMC7877564 DOI: 10.1021/acs.inorgchem.0c03635] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
![]()
Quantum chemical methods for calculating paramagnetic NMR observables are becoming
increasingly accessible and are being included in the inorganic chemistry practice.
Here, we test the performance of these methods in the prediction of proton hyperfine
shifts of two archetypical high-spin pentacoordinate nickel(II) complexes (NiSAL-MeDPT
and NiSAL-HDPT), which, for a variety of reasons, turned out to be perfectly suited to
challenge the predictions to the finest level of detail. For NiSAL-MeDPT, new NMR
experiments yield an assignment that perfectly matches the calculations. The slightly
different hyperfine shifts from the two “halves” of the molecules related
by a pseudo-C2 axis, which are experimentally divided into
two well-defined spin systems, are also straightforwardly distinguished by the
calculations. In the case of NiSAL-HDPT, for which no X-ray structure is available, the
quality of the calculations allowed us to refine its structure using as a starting
template the structure of NiSAL-MeDPT. State-of-the-art
quantum chemical methods and paramagnetism-tailored
NMR experiments provide a deep insight on the relation between the
spectra and the electronic structure for two paramagnetic pentacoordinate
nickel(II) complexes.
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Affiliation(s)
- Enrico Ravera
- Department of Chemistry "Ugo Schiff″, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy.,Magnetic Resonance Center, University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Lucia Gigli
- Department of Chemistry "Ugo Schiff″, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy.,Magnetic Resonance Center, University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Barbara Czarniecki
- Bruker Biospin Corporation, Industriestrasse 26, 8117 Fällanden, Switzerland
| | - Lucas Lang
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Rainer Kümmerle
- Bruker Biospin Corporation, Industriestrasse 26, 8117 Fällanden, Switzerland
| | - Giacomo Parigi
- Department of Chemistry "Ugo Schiff″, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy.,Magnetic Resonance Center, University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Mario Piccioli
- Department of Chemistry "Ugo Schiff″, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy.,Magnetic Resonance Center, University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Claudio Luchinat
- Department of Chemistry "Ugo Schiff″, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy.,Magnetic Resonance Center, University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
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16
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Lang L, Ravera E, Parigi G, Luchinat C, Neese F. Solution of a Puzzle: High-Level Quantum-Chemical Treatment of Pseudocontact Chemical Shifts Confirms Classic Semiempirical Theory. J Phys Chem Lett 2020; 11:8735-8744. [PMID: 32930598 PMCID: PMC7584370 DOI: 10.1021/acs.jpclett.0c02462] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 09/15/2020] [Indexed: 06/11/2023]
Abstract
A recently popularized approach for the calculation of pseudocontact shifts (PCSs) based on first-principles quantum chemistry (QC) leads to different results than the classic "semiempirical" equation involving the susceptibility tensor. Studies that attempted a comparison of theory and experiment led to conflicting conclusions with respect to the preferred theoretical approach. In this Letter, we show that after inclusion of previously neglected terms in the full Hamiltonian, one can deduce the semiempirical equations from a rigorous QC-based treatment. It also turns out that in the long-distance limit, one can approximate the complete A tensor in terms of the g tensor. By means of Kohn-Sham density functional theory calculations, we numerically confirm the long-distance expression for the A tensor and the theoretically predicted scaling behavior of the different terms. Our derivation suggests a computational strategy in which one calculates the susceptibility tensor and inserts it into the classic equation for the PCS.
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Affiliation(s)
- Lucas Lang
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Enrico Ravera
- Magnetic
Resonance Center (CERM), University of Florence,
and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine
(CIRMMP), via Sacconi
6, Sesto Fiorentino 50019, Italy
- Department
of Chemistry “Ugo Schiff”, University of Florence, via della Lastruccia 3, Sesto Fiorentino 50019, Italy
| | - Giacomo Parigi
- Magnetic
Resonance Center (CERM), University of Florence,
and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine
(CIRMMP), via Sacconi
6, Sesto Fiorentino 50019, Italy
- Department
of Chemistry “Ugo Schiff”, University of Florence, via della Lastruccia 3, Sesto Fiorentino 50019, Italy
| | - Claudio Luchinat
- Magnetic
Resonance Center (CERM), University of Florence,
and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine
(CIRMMP), via Sacconi
6, Sesto Fiorentino 50019, Italy
- Department
of Chemistry “Ugo Schiff”, University of Florence, via della Lastruccia 3, Sesto Fiorentino 50019, Italy
| | - Frank Neese
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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17
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Pavlov AA, Nehrkorn J, Zubkevich SV, Fedin MV, Holldack K, Schnegg A, Novikov VV. A Synergy and Struggle of EPR, Magnetometry and NMR: A Case Study of Magnetic Interaction Parameters in a Six-Coordinate Cobalt(II) Complex. Inorg Chem 2020; 59:10746-10755. [DOI: 10.1021/acs.inorgchem.0c01191] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Alexander A. Pavlov
- A.N.Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, Moscow 119991, Russia
- Moscow Institute of Physics and Technology,
Institutskiy per. 9, Dolgoprudny, Moscow 141701, Russia
| | - Joscha Nehrkorn
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
| | | | - Matvey V. Fedin
- International Tomography Center, SB RAS, Institutskaya
3A, Novosibirsk 630090, Russia
- Novosibirsk State University, Novosibirsk 630090, Russia
| | - Karsten Holldack
- Helmholtz-Zentrum für Materialien und Energie GmbH (HZB), Albert-Einstein-Straße 15, D-12489 Berlin, Germany
| | - Alexander Schnegg
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
| | - Valentin V. Novikov
- A.N.Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, Moscow 119991, Russia
- Moscow Institute of Physics and Technology,
Institutskiy per. 9, Dolgoprudny, Moscow 141701, Russia
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18
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Pyykkönen A, Feher R, Köhler FH, Vaara J. Paramagnetic Pyrazolylborate Complexes Tp 2M and Tp* 2M: 1H, 13C, 11B, and 14N NMR Spectra and First-Principles Studies of Chemical Shifts. Inorg Chem 2020; 59:9294-9307. [PMID: 32558559 DOI: 10.1021/acs.inorgchem.0c01176] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The paramagnetic pyrazolylborates Tp2M and Tp*2M (M = Cu, Ni, Co, Fe, Mn, Cr, V) as well as [Tp2M]+ and [Tp*2M]+ (M = Fe, Cr, V) have been synthesized and their NMR spectra recorded. The 1H signal shift ranges vary from ∼30 ppm (Cu(II) and V(III)) to ∼220 ppm (Co(II)), and the 13C signal shift ranges from ∼180 ppm (Fe(III)) to ∼1150 ppm (Cr(II)). The 11B and 14N shifts are ∼360 and ∼730 ppm, respectively. Both negative and positive shifts have been observed for all nuclei. The narrow NMR signals of the Co(II), Fe(II), Fe(III), and V(III) derivatives provide resolved 13C,1H couplings. All chemical shifts have been calculated from first-principles on a modern version of Kurland-McGarvey theory which includes optimized structures, zero-field splitting, and g tensors, as well as signal shift contributions. Temperature dependence in the Fe(II) spin-crossover complex results from the equilibrium of the ground singlet and the excited quintet. We illustrate both the assignment and analysis capabilities, as well as the shortcomings of the current computational methodology.
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Affiliation(s)
- Ari Pyykkönen
- NMR Research Unit, University of Oulu, P.O. Box 3000, Oulu FI-90014, Finland
| | - Robert Feher
- Department Chemie, Technische Universität München, D-85748 Garching, Germany
| | - Frank H Köhler
- Department Chemie, Technische Universität München, D-85748 Garching, Germany
| | - Juha Vaara
- NMR Research Unit, University of Oulu, P.O. Box 3000, Oulu FI-90014, Finland
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19
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Belov AS, Voloshin YZ, Pavlov AA, Nelyubina YV, Belova SA, Zubavichus YV, Avdeeva VV, Efimov NN, Malinina EA, Zhizhin KY, Kuznetsov NT. Solvent-Induced Encapsulation of Cobalt(II) Ion by a Boron-Capped tris-Pyrazoloximate. Inorg Chem 2020; 59:5845-5853. [PMID: 31984742 DOI: 10.1021/acs.inorgchem.9b03335] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Boron-cross-linked cobalt(II) pseudoclathrochelate was obtained by the template reaction of 2-acetylpyrazoloxime, phenylboronic acid, and a new DMF cobalt(II) solvato complex with a decachloro-closo-decaborate dianion. As confirmed by single-crystal X-ray diffraction, this complex crystallizes with two symmetry-independent cobalt(II) pseudoclathrochelate cations, one decachloro-closo-decaborate dianion, one benzene, one dichloromethane solvent molecule, and two molecules of DMF. The latter act as pseudocapping fragments to the monocapped tris-pyrazoloximate ligands by forming N-H···O hydrogen bonds with their pyrazole groups. The CoIIN6-coordination polyhedra adopt a nearly ideal TP geometry with distortion angles φ equal to 1.22(16) and 2.58(17)° for two symmetry-independent pseudoclathrochelate cations, both containing the encapsulated cobalt(II) ion in its high-spin state (Co-N 2.115(4)-2.198(3) Å). Magnetic properties of this complex were studied both by dc-magnetometry and by solution-state NMR spectroscopy to reveal a high magnetic anisotropy, thus suggesting a large magnetic susceptibility tensor anisotropy (25.8 × 10-32 m3 at 298 K) and a large negative zero-field splitting energy (-85 cm-1). The results of magnetometry studies in the ac magnetic field suggest a single molecule magnet behavior of this TP complex with an effective magnetization reversal barrier of approximately 130 cm-1. Its pseudocapping DMF molecules that form H-bonds with tris-pyrazoloximate fragments are easy to substitute by strong H-bond acceptors, such as chloride ions and di- and tetramethylureas, thus affecting the magnetic properties of a whole pseudomacrobicyclic paramagnetic system.
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Affiliation(s)
- Alexander S Belov
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilova st., Moscow, 119991, Russia
| | - Yan Z Voloshin
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilova st., Moscow, 119991, Russia.,Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 31 Leninsky prosp., Moscow, 119991, Russia
| | - Alexander A Pavlov
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilova st., Moscow, 119991, Russia
| | - Yulia V Nelyubina
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilova st., Moscow, 119991, Russia.,Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 31 Leninsky prosp., Moscow, 119991, Russia
| | - Svetlana A Belova
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilova st., Moscow, 119991, Russia
| | - Yan V Zubavichus
- National Research Centre "Kurchatov Institute", 1 Kurchatova pl., Moscow, 123182, Russia.,Boreskov Institute of Catalysis of the Siberian Branch of the Russian Academy of Sciences, 5 Lavrentiev Ave., 630090 Novosibirsk, Russia
| | - Varvara V Avdeeva
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 31 Leninsky prosp., Moscow, 119991, Russia
| | - Nikolay N Efimov
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 31 Leninsky prosp., Moscow, 119991, Russia
| | - Elena A Malinina
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 31 Leninsky prosp., Moscow, 119991, Russia
| | - Konstantin Yu Zhizhin
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 31 Leninsky prosp., Moscow, 119991, Russia
| | - Nikolay T Kuznetsov
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 31 Leninsky prosp., Moscow, 119991, Russia
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20
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Meng-Xue Z, Ning R, Jin-Yong H, Jian-Jun Z, Da-Qi W. Construction of lanthanide complexes based on 3,4-dichlorobenzoic acid and 5,5′-dimethyl-2,2′-bipyridine: Supramolecular structures, thermodynamic properties and luminescent behaviors. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.05.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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21
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Diego R, Pavlov A, Darawsheh M, Aleshin D, Nehrkorn J, Nelyubina Y, Roubeau O, Novikov V, Aromí G. Coordination [Co II2] and [Co IIZn II] Helicates Showing Slow Magnetic Relaxation. Inorg Chem 2019; 58:9562-9566. [PMID: 31283191 DOI: 10.1021/acs.inorgchem.9b01334] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The slow magnetic relaxation of CoII ions in the elusive intermediate geometry between the trigonal prism and antiprism has been studied on the new [Co2L3]4+ and [CoZnL3]4+ coordination helicates [L is a bis(pyrazolylpyridine) ligand]. Solution paramagnetic 1H NMR and solid-state magnetization measurements unveil single-molecule-magnet behavior with small axial anisotropy, as predicted previously.
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Affiliation(s)
- Rosa Diego
- Departament de Química Inorgànica i Orgànica , Universitat de Barcelona , Diagonal 645 , 08028 Barcelona , Spain.,Institute of Nanoscience and Nanotechnology of the Unirvesity of Barcelona (IN2UB) , Barcelona , Spain
| | - Alexander Pavlov
- A. N. Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , Vavilova strasse 28 , Moscow , Russia.,Moscow Institute of Physics and Technology , Institutskiy per. 9, Dolgoprudny, Moscow , Russia
| | - Mohanad Darawsheh
- Departament de Química Inorgànica i Orgànica , Universitat de Barcelona , Diagonal 645 , 08028 Barcelona , Spain
| | - Dmitry Aleshin
- A. N. Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , Vavilova strasse 28 , Moscow , Russia.,Mendeleev University of Chemical Technology of Russia , Miusskaya sq. 9 , 125047 Moscow , Russia
| | - Joscha Nehrkorn
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , Germany
| | - Yulia Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , Vavilova strasse 28 , Moscow , Russia.,Moscow Institute of Physics and Technology , Institutskiy per. 9, Dolgoprudny, Moscow , Russia
| | - Olivier Roubeau
- Instituto de Ciencia de Materiales de Aragón (ICMA) , CSIC and Universidad de Zaragoza , 50009 Zaragoza , Spain
| | - Valentin Novikov
- A. N. Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , Vavilova strasse 28 , Moscow , Russia.,Moscow Institute of Physics and Technology , Institutskiy per. 9, Dolgoprudny, Moscow , Russia
| | - Guillem Aromí
- Departament de Química Inorgànica i Orgànica , Universitat de Barcelona , Diagonal 645 , 08028 Barcelona , Spain.,Institute of Nanoscience and Nanotechnology of the Unirvesity of Barcelona (IN2UB) , Barcelona , Spain
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22
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Hiller M, Sittel T, Wadepohl H, Enders M. A New Class of Lanthanide Complexes with Three Ligand Centered Radicals: NMR Evaluation of Ligand Field Energy Splitting and Magnetic Coupling. Chemistry 2019; 25:10668-10677. [PMID: 31050369 DOI: 10.1002/chem.201901388] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Indexed: 11/09/2022]
Abstract
Combination of three radical anionic Ph-BIAN ligands (Ph-BIAN=bis-(phenylimino)-acenaphthenequinone) with lanthanoid ions leads to a series of homoleptic, six-coordinate complexes of the type Ln(Ph-BIAN)3 . Magnetic coupling data were measured by paramagnetic solution NMR spectroscopy. Combining 1 H NMR with 2 H NMR of partially deuterated compounds allowed a detailed study of the magnetic susceptibility anisotropies over a large temperature range. The observed chemical shifts were separated into ligand- and metal-centered contributions by comparison with the Y analogue (diamagnetic at the metal). The metal-centered contributions of the complexes with the paramagnetic ions could then be separated into pseudocontact and Fermi contact shifts. The latter is large within the Ph-BIAN scaffold, which shows that magnetic coupling is significant between the lanthanide ion and the radical ligand. Pseudocontact shifts were further correlated to structural data obtained from X-ray diffraction experiments. Ligand-field parameters were determined by fitting the temperature dependence of the observed magnetic susceptibility anisotropies. The electronic structure determined by this approach shows, that the Er and Tm analogues are candidates for single molecule magnets (SMM). These results demonstrate the possibilities for the application of NMR spectroscopy in investigations of paramagnetic systems in general and single molecule magnets in particular.
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Affiliation(s)
- Markus Hiller
- Institute of Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Thomas Sittel
- Institute of Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Hubert Wadepohl
- Institute of Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Markus Enders
- Institute of Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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23
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Pavlov AA, Aleshin DY, Savkina SA, Belov AS, Efimov NN, Nehrkorn J, Ozerov M, Voloshin YZ, Nelyubina YV, Novikov VV. A Trigonal Prismatic Cobalt(II) Complex as a Single Molecule Magnet with a Reduced Contribution from Quantum Tunneling. Chemphyschem 2019; 20:1001-1005. [PMID: 30897255 DOI: 10.1002/cphc.201900219] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Indexed: 01/27/2023]
Abstract
Herein, we report a new trigonal prismatic cobalt(II) complex that behaves as a single molecule magnet. The obtained zero-field splitting, which is also directly accessed by THz-EPR spectroscopy (-102.5 cm-1 ), results in a large magnetization reversal barrier U of 205 cm-1 . Its effective value, however, is much lower (101 cm-1 ), even though there is practically no contribution from quantum tunneling to magnetization relaxation.
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Affiliation(s)
- Alexander A Pavlov
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991, Moscow, Russia
| | - Dmitry Y Aleshin
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991, Moscow, Russia.,D. Mendeleyev University of Chemical Technology of Russia, Miusskaya pl. 9, 125047, Moscow, Russia
| | - Svetlana A Savkina
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991, Moscow, Russia
| | - Alexander S Belov
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991, Moscow, Russia
| | - Nikolay N Efimov
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii prosp., 31, 117901, Moscow, Russia
| | - Joscha Nehrkorn
- National High Magnetic Field Laboratory & Florida State University 1800 E. Paul Dirac Drive Tallahassee, FL 32310-3706, USA.,Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory & Florida State University 1800 E. Paul Dirac Drive Tallahassee, FL 32310-3706, USA
| | - Yan Z Voloshin
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991, Moscow, Russia.,Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii prosp., 31, 117901, Moscow, Russia
| | - Yulia V Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991, Moscow, Russia.,Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii prosp., 31, 117901, Moscow, Russia
| | - Valentin V Novikov
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 119991, Moscow, Russia
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24
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Autillo M, Guerin L, Dumas T, Grigoriev MS, Fedoseev AM, Cammelli S, Solari PL, Guillaumont D, Guilbaud P, Moisy P, Bolvin H, Berthon C. Insight of the Metal-Ligand Interaction in f-Element Complexes by Paramagnetic NMR Spectroscopy. Chemistry 2019; 25:4435-4451. [PMID: 30815930 DOI: 10.1002/chem.201805858] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/14/2019] [Indexed: 02/05/2023]
Abstract
The magnetic properties of LnIII and AnIII complexes formed with dipicolinate ligands have been studied by NMR spectroscopy. To know precisely the geometries of these complexes, a crystallographic study by single-crystal X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) in solution was performed. Several methods to separate the paramagnetic shifts observed in the NMR spectra were applied to these complexes. Methods using a number of nuclei of the dipicolinate ligands revealed an abrupt change in the geometries of the complexes and a metal-ligand interaction in the middle of the lanthanide series. A study of the variation of the paramagnetic shifts with temperature demonstrated that higher-order terms of the dipolar and contact contributions are required, especially for the lightest LnIII and almost all the studied AnIII . Bleaney's parameters <Sz >a and C a D relating to the contact and dipolar terms, respectively, were deduced from experimental data and compared with the results of ab initio calculations. Quite a good agreement was found for the temperature dependencies of <Sz >a and C a D . However, the C a D values obtained from cation magnetic anisotropy calculations showed some discrepancies with the values derived from Bleaney's equation defined for LnIII . Other parameters, such as the crystal field parameter and the hyperfine constants Fi obtained from the experimental data of the [An(ethyl-dpa)3 ]3- complexes (ethyl-dpa=4-ethyl-2,6-dipicolinic acid), are at odds with the assumptions underlying Bleaney's theory.
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Affiliation(s)
- Matthieu Autillo
- CEA, Nuclear Energy Division, Research Department of Mining, and Fuel Recycling Processes, BP 17171, F-30207, Bagnols sur Cèze, France
| | - Laetitia Guerin
- CEA, Nuclear Energy Division, Research Department of Mining, and Fuel Recycling Processes, BP 17171, F-30207, Bagnols sur Cèze, France
| | - Thomas Dumas
- CEA, Nuclear Energy Division, Research Department of Mining, and Fuel Recycling Processes, BP 17171, F-30207, Bagnols sur Cèze, France
| | - Mikhail S Grigoriev
- A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, 119071, Russia
| | - Alexandre M Fedoseev
- A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, 119071, Russia
| | - Sebastiano Cammelli
- Synchrotron SOLEIL, L'orme des Merisiers, Saint Aubins, BP 48, F-91192, Gif sur Yvette cedex, France
| | - Pier Lorenzo Solari
- Synchrotron SOLEIL, L'orme des Merisiers, Saint Aubins, BP 48, F-91192, Gif sur Yvette cedex, France
| | - Dominique Guillaumont
- CEA, Nuclear Energy Division, Research Department of Mining, and Fuel Recycling Processes, BP 17171, F-30207, Bagnols sur Cèze, France
| | - Philippe Guilbaud
- CEA, Nuclear Energy Division, Research Department of Mining, and Fuel Recycling Processes, BP 17171, F-30207, Bagnols sur Cèze, France
| | - Philippe Moisy
- CEA, Nuclear Energy Division, Research Department of Mining, and Fuel Recycling Processes, BP 17171, F-30207, Bagnols sur Cèze, France
| | - Hélène Bolvin
- Laboratoire de Physique et de Chimie Quantiques, Université Toulouse 3, 118 Route de Narbonne, 31062, Toulouse, France
| | - Claude Berthon
- CEA, Nuclear Energy Division, Research Department of Mining, and Fuel Recycling Processes, BP 17171, F-30207, Bagnols sur Cèze, France
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25
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Suturina EA, Mason K, Botta M, Carniato F, Kuprov I, Chilton NF, McInnes EJL, Vonci M, Parker D. Periodic trends and hidden dynamics of magnetic properties in three series of triazacyclononane lanthanide complexes. Dalton Trans 2019; 48:8400-8409. [DOI: 10.1039/c9dt01069f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In three structurally related series of nine-coordinate lanthanide(iii) complexes, solution NMR studies and DFT/CASSCF calculations have provided key information on the magnetic susceptibility anisotropy.
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Affiliation(s)
| | - Kevin Mason
- Department of Chemistry
- Durham University
- Durham DH1 3LE
- UK
| | - Mauro Botta
- Dipartimento di Scienze e Innovazione Tecnologica
- Università del Piemonte Orientale “Amedeo Avogadro”
- 15121 Alessandria
- Italy
| | - Fabio Carniato
- Dipartimento di Scienze e Innovazione Tecnologica
- Università del Piemonte Orientale “Amedeo Avogadro”
- 15121 Alessandria
- Italy
| | - Ilya Kuprov
- Chemistry
- University of Southampton
- Southampton
- UK
| | | | | | - Michele Vonci
- School of Chemistry
- University of Manchester
- Manchester M13 9PL
- UK
| | - David Parker
- Department of Chemistry
- Durham University
- Durham DH1 3LE
- UK
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26
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Pavlov AA, Nehrkorn J, Pankratova YA, Ozerov M, Mikhalyova EA, Polezhaev AV, Nelyubina YV, Novikov VV. Detailed electronic structure of a high-spin cobalt(ii) complex determined from NMR and THz-EPR spectroscopy. Phys Chem Chem Phys 2019; 21:8201-8204. [DOI: 10.1039/c9cp01474h] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Here we report a combined use of THz-EPR and paramagnetic NMR spectroscopy for obtaining a detailed electronic structure of a high-spin cobalt(ii) complex.
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Affiliation(s)
- Alexander A. Pavlov
- A.N.Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Moscow
- Russia
- Moscow Institute of Physics and Technology
| | - Joscha Nehrkorn
- National High Magnetic Field Laboratory & Florida State University
- 1800 E. Paul Dirac Drive
- Tallahassee
- USA
- Max Planck Institute for Chemical Energy Conversion
| | - Yanina A. Pankratova
- A.N.Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Moscow
- Russia
- Lomonosov Moscow State University
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory & Florida State University
- 1800 E. Paul Dirac Drive
- Tallahassee
- USA
| | - Elena A. Mikhalyova
- L.V.Pisarzhevskii Institute of Physical Chemistry of the National Academy of Sciences of the Ukraine
- Kiev
- Ukraine
| | - Alexander V. Polezhaev
- A.N.Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Moscow
- Russia
- Bauman Moscow State Technical University
| | - Yulia V. Nelyubina
- A.N.Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Moscow
- Russia
- Moscow Institute of Physics and Technology
| | - Valentin V. Novikov
- A.N.Nesmeyanov Institute of Organoelement Compounds
- Russian Academy of Sciences
- Moscow
- Russia
- Moscow Institute of Physics and Technology
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27
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Pavlov A, Savkina SA, Belov AS, Voloshin YZ, Nelyubina YV, Novikov VV. Very Large Magnetic Anisotropy of Cage Cobalt(II) Complexes with a Rigid Cholesteryl Substituent from Paramagnetic NMR Spectroscopy. ACS OMEGA 2018; 3:4941-4946. [PMID: 31458710 PMCID: PMC6641741 DOI: 10.1021/acsomega.8b00772] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 04/27/2018] [Indexed: 05/05/2023]
Abstract
Variable-temperature NMR spectroscopy has recently emerged as a new alternative to the magnetometry methods for studying single molecule magnets. Its use is based on an accurate determination of magnetic susceptibility tensor anisotropy Δχ, which is not always achievable due to some contact contribution to NMR chemical shifts and possible conformational dynamics. Here, we applied this approach to cholesteryl-substituted cage cobalt(II) complexes featuring a very large magnetic anisotropy. Conformational rigidity and large size of the cholesteryl substituent with many magnetically nonequivalent nuclei resulted in an excellent convergence of experimental and calculated 1H and 13C chemical shifts, thus allowing for the determination of Δχ value for all of the synthesized cobalt(II) complexes with a very high accuracy and providing a more reliable zero-field splitting energy for further calculations.
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Affiliation(s)
- Alexander
A. Pavlov
- Nesmeyanov
Institute of Organoelement Compounds, Russian
Academy of Sciences, Vavilova Street, 28, 119991 Moscow, Russia
| | - Svetlana A. Savkina
- Nesmeyanov
Institute of Organoelement Compounds, Russian
Academy of Sciences, Vavilova Street, 28, 119991 Moscow, Russia
| | - Alexander S. Belov
- Nesmeyanov
Institute of Organoelement Compounds, Russian
Academy of Sciences, Vavilova Street, 28, 119991 Moscow, Russia
| | - Yan Z. Voloshin
- Nesmeyanov
Institute of Organoelement Compounds, Russian
Academy of Sciences, Vavilova Street, 28, 119991 Moscow, Russia
- Kurnakov
Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii prospekt, 31, 117901 Moscow, Russia
| | - Yulia V. Nelyubina
- Nesmeyanov
Institute of Organoelement Compounds, Russian
Academy of Sciences, Vavilova Street, 28, 119991 Moscow, Russia
- Kurnakov
Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii prospekt, 31, 117901 Moscow, Russia
| | - Valentin V. Novikov
- Nesmeyanov
Institute of Organoelement Compounds, Russian
Academy of Sciences, Vavilova Street, 28, 119991 Moscow, Russia
- E-mail:
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28
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Morita T, Damjanović M, Katoh K, Kitagawa Y, Yasuda N, Lan Y, Wernsdorfer W, Breedlove BK, Enders M, Yamashita M. Comparison of the Magnetic Anisotropy and Spin Relaxation Phenomenon of Dinuclear Terbium(III) Phthalocyaninato Single-Molecule Magnets Using the Geometric Spin Arrangement. J Am Chem Soc 2018; 140:2995-3007. [PMID: 29400960 DOI: 10.1021/jacs.7b12667] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Herein we report the synthesis and characterization of a dinuclear TbIII single-molecule magnet (SMM) with two [TbPc2]0 units connected via a fused-phthalocyaninato ligand. The stable and robust complex [(obPc)Tb(Fused-Pc)Tb(obPc)] (1) was characterized by using synchrotron radiation measurements and other spectroscopic techniques (ESI-MS, FT-IR, UV). The magnetic couplings between the TbIII ions and the two π radicals present in 1 were explored by means of density functional theory (DFT). Direct and alternating current magnetic susceptibility measurements were conducted on magnetically diluted and nondiluted samples of 1, indicating this compound to be an SMM with improved properties compared to those of the well-known [TbPc2]-/0/+ and the axially symmetric dinuclear TbIII phthalocyaninato triple-decker complex (Tb2(obPc)3). Assuming that the probability of quantum tunneling of the magnetization (QTM) occurring in one TbPc2 unit is PQTM, the probability of QTM simultaneously occurring in 1 is PQTM2, meaning that QTM is effectively suppressed. Furthermore, nondiluted samples of 1 underwent slow magnetic relaxation times (τ ≈ 1000 s at 0.1 K), and the blocking temperature (TB) was determined to be ca. 16 K with an energy barrier for spin reversal (Ueff) of 588 cm-1 (847 K) due to D4d geometry and weak inter- and intramolecular magnetic interactions as an exchange bias (Hbias), reducing QTM. Four hyperfine steps were observed by micro-SQUID measurement. Furthermore, solution NMR measurements (one-dimensional, two-dimensional, and dynamic) were done on 1, which led to the determination of the high rotation barrier (83 ± 10 kJ/mol) of the obPc ligand. A comparison with previously reported TbIII triple-decker compounds shows that ambient temperature NMR measurements can indicate improvements in the design of coordination environments for SMMs. A large Ueff causes strong uniaxial magnetic anisotropy in 1, leading to a χax value (1.39 × 10-30 m3) that is larger than that for Tb2(obPc)3 (0.86 × 10-30 m3). Controlling the coordination environment and spin arrangement is an effective technique for suppressing QTM in TbPc2-based SMMs.
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Affiliation(s)
- Takaumi Morita
- Department of Chemistry, Graduate School of Science, Tohoku University , 6-3, Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Marko Damjanović
- Institute of Inorganic Chemistry, Heidelberg University , Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.,Physikalisches Institut and Institute of Nanotechnology, Karlsruhe Institute of Technology , Wolfgang-Gaede-Strasse 1, 76131 Karlsruhe, Germany
| | - Keiichi Katoh
- Department of Chemistry, Graduate School of Science, Tohoku University , 6-3, Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Yasutaka Kitagawa
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University , 1-1 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Nobuhiro Yasuda
- Japan Synchrotron Radiation Research Institute (JASRI) , 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Yanhua Lan
- Physikalisches Institut and Institute of Nanotechnology, Karlsruhe Institute of Technology , Wolfgang-Gaede-Strasse 1, 76131 Karlsruhe, Germany
| | - Wolfgang Wernsdorfer
- Physikalisches Institut and Institute of Nanotechnology, Karlsruhe Institute of Technology , Wolfgang-Gaede-Strasse 1, 76131 Karlsruhe, Germany.,CNRS and Université Grenoble Alpes, Institut Néel , 38042 Grenoble, France
| | - Brian K Breedlove
- Department of Chemistry, Graduate School of Science, Tohoku University , 6-3, Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Markus Enders
- Institute of Inorganic Chemistry, Heidelberg University , Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
| | - Masahiro Yamashita
- Department of Chemistry, Graduate School of Science, Tohoku University , 6-3, Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan.,WPI Research Center, Advanced Institute for Materials Research, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.,School of Materials Science and Engineering, Nankai University , Tianjin 300350, China
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