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Patyk-Kaźmierczak E, Izquierdo-Ruiz F, Lobato A, Kaźmierczak M, Moszczyńska I, Olejniczak A, Recio JM. The curious case of proton migration under pressure in the malonic acid and 4,4'-bipyridine cocrystal. IUCRJ 2024; 11:168-181. [PMID: 38275161 PMCID: PMC10916288 DOI: 10.1107/s2052252524000344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 01/09/2024] [Indexed: 01/27/2024]
Abstract
In the search for new active pharmaceutical ingredients, the precise control of the chemistry of cocrystals becomes essential. One crucial step within this chemistry is proton migration between cocrystal coformers to form a salt, usually anticipated by the empirical ΔpKa rule. Due to the effective role it plays in modifying intermolecular distances and interactions, pressure adds a new dimension to the ΔpKa rule. Still, this variable has been scarcely applied to induce proton-transfer reactions within these systems. In our study, high-pressure X-ray diffraction and Raman spectroscopy experiments, supported by DFT calculations, reveal modifications to the protonation states of the 4,4'-bipyridine (BIPY) and malonic acid (MA) cocrystal (BIPYMA) that allow the conversion of the cocrystal phase into ionic salt polymorphs. On compression, neutral BIPYMA and monoprotonated (BIPYH+MA-) species coexist up to 3.1 GPa, where a phase transition to a structure of P21/c symmetry occurs, induced by a double proton-transfer reaction forming BIPYH22+MA2-. The low-pressure C2/c phase is recovered at 2.4 GPa on decompression, leading to a 0.7 GPa hysteresis pressure range. This is one of a few studies on proton transfer in multicomponent crystals that shows how susceptible the interconversion between differently charged species is to even slight pressure changes, and how the proton transfer can be a triggering factor leading to changes in the crystal symmetry. These new data, coupled with information from previous reports on proton-transfer reactions between coformers, extend the applicability of the ΔpKa rule incorporating the pressure required to induce salt formation.
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Affiliation(s)
- Ewa Patyk-Kaźmierczak
- Facuty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, Poznań 61-614, Poland
| | - Fernando Izquierdo-Ruiz
- MALTA-Consolider Team and Departamento de Química Física, University Complutense of Madrid, Avda. de Séneca, 2 Ciudad Universitaria, Madrid 28040, Spain
| | - Alvaro Lobato
- MALTA-Consolider Team and Departamento de Química Física, University Complutense of Madrid, Avda. de Séneca, 2 Ciudad Universitaria, Madrid 28040, Spain
| | - Michał Kaźmierczak
- Facuty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, Poznań 61-614, Poland
| | - Ida Moszczyńska
- Facuty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, Poznań 61-614, Poland
| | - Anna Olejniczak
- Facuty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, Poznań 61-614, Poland
| | - J. Manuel Recio
- MALTA-Consolider Team and Departamento de Química Física y Analítica, University of Oviedo, Julián Clavería n° 8, Oviedo 33006, Spain
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2
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Titiš J, Rajnák C, Boča R. Limitations on the D-Parameter in Ni(II) Complexes. J Phys Chem A 2023; 127:6412-6424. [PMID: 37494700 DOI: 10.1021/acs.jpca.3c02543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
A number of hexacoordinate, pentacoordinate, and tetracoordinate Ni(II) complexes have been investigated by applying ab initio CASSCF + NEVPT2 + SOC calculations and Generalized Crystal Field Theory. The geometry of the coordination polyhedron covers D4h, D3h, D2h, D2d, C4v, C3v, and C2v symmetry. The calculated spin-Hamiltonian parameters D and E were compared to the available experimental data. The limiting values of the D-parameter in the class of Ni(II) complexes are identified. Magnetic anisotropy in Ni(II) complexes, expressed by the axial zero-field splitting parameter D, seriously depends upon the ground and first excited electronic states. In hexacoordinate complexes, the ground electronic term is nondegenerate 3B1g for the D4h symmetry; D is slightly positive or negative. In tetracoordinate systems, D is only positive when the electronic ground state is nondegenerate 3A or 3B; this diverges on the τ4 path when oblate bisphenoid approaches the prolate geometry and a level crossing with 3E occurs. In pentacoordinate systems, D could be extremely negative when approaching a trigonal bipyramid (Addison index τ5 ∼ 1, ground state 3E″). In pentacoordinate Ni(II) complexes with the D3h and C3v symmetry of the coordination polyhedron, the ground electronic term is orbitally doubly degenerate which causes the D-parameter stays undefined. It is emphasized that one has to inspect compositions of the spin-orbit multiplets from the spin states |MS⟩ and check whether the weights confirm the expected spin-Hamiltonian picture: with D > 0, the ground state contains a dominant part of |0⟩ (close to 100%) whereas with D < 0 the spin-orbit doublet is formed of |±1⟩ with high weights (approaching 50 + 50%). The calculations show that the situations are not black and white, and the mixing of the states might be more complex especially when the rhombic zero-field splitting parameter E is in the play. In the case of the 3E ground term, six spin-orbit multiplets are formed by mixing six |MS⟩ states from the ground and quasi-degenerate excited states.
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Affiliation(s)
- Ján Titiš
- Department of Chemistry, Faculty of Natural Sciences, University of SS Cyril and Methodius, 91701 Trnava, Slovakia
| | - Cyril Rajnák
- Department of Chemistry, Faculty of Natural Sciences, University of SS Cyril and Methodius, 91701 Trnava, Slovakia
| | - Roman Boča
- Department of Chemistry, Faculty of Natural Sciences, University of SS Cyril and Methodius, 91701 Trnava, Slovakia
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3
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Georgiev M, Chamati H. Magnetic Behavior of Trigonal (Bi-)pyramidal 3d 8 Mononuclear Nanomagnets: The Case of [Ni(MDABCO) 2Cl 3]ClO 4. ACS OMEGA 2023; 8:28640-28650. [PMID: 37576657 PMCID: PMC10413474 DOI: 10.1021/acsomega.3c03208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 06/30/2023] [Indexed: 08/15/2023]
Abstract
This paper attempts to shed light on the origin of the magnetic behavior specific to trigonal bi- and pyramidal 3d8 mono- and polynuclear nanomagnets. The focus lies on entirely unraveling the system's intrinsic microscopic mechanisms and fundamental quantum mechanical relations governing the underlying electron dynamics. To this end, we develop a self-consistent approach to characterize, in great detail, all electron correlations and the ensuing fine structure of the energy spectra of a broad class of 3d8 systems. The mathematical framework is based on the multiconfigurational self-consistent field method and is devised to account for prospective quantum mechanical constraints that may confine the electron orbital dynamics while preserving the properties of all measurable quantities. We successfully characterize the experimentally observed magnetic anisotropy properties of a slightly distorted trigonal bipyramidal Ni2+ coordination complex, demonstrating that such compounds do not exhibit intrinsic huge zero-field splitting and inherent giant magnetic anisotropy. We reproduce qualitatively and quantitatively the behavior of the low-field magnetic susceptibility, magnetization, low-, and high-field electron paramagnetic resonance spectroscopy measurements and provide an in-depth analysis of the obtained results.
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Affiliation(s)
- Miroslav Georgiev
- Bulgarian Academy of Sciences, G Nadjakov Institute of Solid State Physics, Tsarigradsko Chaussée 72, 1784 Sofia, Bulgaria
| | - Hassan Chamati
- Bulgarian Academy of Sciences, G Nadjakov Institute of Solid State Physics, Tsarigradsko Chaussée 72, 1784 Sofia, Bulgaria
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4
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Joshi S, Roy Chowdhury S, Mishra S. Spin-state energetics and magnetic anisotropy in penta-coordinated Fe(III) complexes with different axial and equatorial ligand environments. Phys Chem Chem Phys 2023. [PMID: 37367302 DOI: 10.1039/d3cp02182c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
The penta-coordinated trigonal-bi-pyramidal (TBP) Fe(III) complex (PMe2Ph)2FeCl3 shows a reduced magnetic anisotropy in its intermediate-spin (IS) state as compared to its methyl-analog (PMe3)2Fe(III)Cl3. In this work, the ligand environment in (PMe2Ph)2FeCl3 is systematically altered by replacing the axial -P with -N and -As, the equatorial -Cl with other halides, and the axial methyl group with an acetyl group. This has resulted in a series of Fe(III) TBP complexes modelled in their IS and high-spin (HS) states. Lighter ligands -N and -F stabilize the complex in the HS state, while the magnetically anisotropic IS state is stabilized by -P and -As at the axial site, and -Cl, -Br, and -I at the equatorial site. Larger magnetic anisotropies appear for complexes with nearly degenerate ground electronic states that are well separated from the higher excited states. This requirement, largely controlled by the d-orbital splitting pattern due to the changing ligand field, is achieved with a certain combination of axial and equatorial ligands, such as -P and -Br, -As and -Br, and -As and -I. In most cases, the acetyl group at the axial site enhances the magnetic anisotropy compared to its methyl counterpart. In contrast, the presence of -I at the equatorial site compromises the uniaxial type of anisotropy of the Fe(III) complex leading to an enhanced rate of quantum tunneling of magnetization.
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Affiliation(s)
- Shalini Joshi
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India.
| | | | - Sabyashachi Mishra
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India.
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Parmar VS, Thiel AM, Nabi R, Gransbury GK, Norre MS, Evans P, Corner SC, Skelton JM, Chilton NF, Mills DP, Overgaard J. Influence of pressure on a dysprosocenium single-molecule magnet. Chem Commun (Camb) 2023; 59:2656-2659. [PMID: 36780133 PMCID: PMC9972519 DOI: 10.1039/d2cc06722f] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The effects of external pressure on a high-performing dysprosocenium single-molecule magnet are investigated using a combination of X-ray diffraction, magnetometry and theoretical calculations. The effective energy barrier (Ueff) decreases from ca. 1300 cm-1 at ambient pressure to ca. 1125 cm-1 at 3 GPa. Our results indicate that compression < 1.2 GPa has a negligible effect on the Orbach process, but magnetic relaxation > 1 GPa increases via Raman relaxation and/or quantum tunnelling of magnetisation.
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Affiliation(s)
- Vijay S. Parmar
- Department of Chemistry, Aarhus UniversityLangelandsgade 140Aarhus C DK-8000Denmark
| | - Andreas M. Thiel
- Department of Chemistry, Aarhus UniversityLangelandsgade 140Aarhus C DK-8000Denmark
| | - Rizwan Nabi
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Gemma K. Gransbury
- Department of Chemistry, The University of ManchesterOxford RoadManchester M13 9PLUK
| | - Marie S. Norre
- Department of Chemistry, Aarhus UniversityLangelandsgade 140Aarhus C DK-8000Denmark
| | - Peter Evans
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Sophie C. Corner
- Department of Chemistry, The University of ManchesterOxford RoadManchester M13 9PLUK
| | - Jonathan M. Skelton
- Department of Chemistry, The University of ManchesterOxford RoadManchester M13 9PLUK
| | - Nicholas F. Chilton
- Department of Chemistry, The University of ManchesterOxford RoadManchester M13 9PLUK
| | - David P. Mills
- Department of Chemistry, The University of ManchesterOxford RoadManchester M13 9PLUK
| | - Jacob Overgaard
- Department of Chemistry, Aarhus University, Langelandsgade 140, Aarhus C DK-8000, Denmark.
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6
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Fine Structure and the Huge Zero-Field Splitting in Ni 2+ Complexes. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27248887. [PMID: 36558020 PMCID: PMC9784865 DOI: 10.3390/molecules27248887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/11/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
We perform a thorough study of the ground state magnetic properties of nickel-based 3d8 complexes. This includes an in-depth analysis of the contribution of the crystal field, spin exchange and spin-orbit interactions to the ground state magnetic properties. Of particular interest to the current investigation are the presence and occurrence of non-trivial zero-field splitting. The study focuses on the cases of Ni2+ ideal octahedral, trigonal bipyramidal, square planar and tetrahedral geometries. We provide results for the complete energy spectrum, the fine structure related to the ground state and the second set of excited states, low-field magnetic susceptibility and magnetization. In addition, we examine the zero-field fine structure in square pyramidal, trigonal pyramidal and trigonal planar complexes. The obtained results unequivocally show that a moderate or highly coordinated 3d8 complex can neither exhibit spin-orbit-driven large and giant magnetic anisotropy nor a huge zero-field splitting. Moreover, in the trigonal bipyramidal coordination, a fine structure associated to the ground state cannot result from the spin-orbit coupling alone.
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7
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Georgiev M, Chamati H. Single-Ion Magnets with Giant Magnetic Anisotropy and Zero-Field Splitting. ACS OMEGA 2022; 7:42664-42673. [PMID: 36467950 PMCID: PMC9713882 DOI: 10.1021/acsomega.2c06119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 11/02/2022] [Indexed: 06/17/2023]
Abstract
The design of mononuclear molecular nanomagnets exhibiting a huge energy barrier to the reversal of magnetization have seen a surge of interest during the last few decades due to their potential technological applications. More specifically, single-ion magnets are peculiarly attractive by virtue of their rich quantum behavior and distinct fine structure. These are viable candidates for implementation as single-molecule high-density information storage devices and other applications in future quantum technologies. The present review presents the comprehensive state of the art in the topic of single-ion magnets possessing an eminent magnetization-reversal barrier, very slow magnetic relaxation and high blocking temperature. We turn our attention to the achievements in the synthesis of 3d and 4f single-ion magnets during the last two decades and discuss the observed magnetostructural properties underlying the anisotropy behavior and the ensuing remanence. Furthermore, we highlight the fundamental theoretical aspects to shed light on the complex behavior of these nanosized magnetic entities. In particular, we focus on key notions, such as zero-field splitting, anisotropy energy and quantum tunneling of the magnetization and their interdependence.
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Affiliation(s)
- Miroslav Georgiev
- G Nadjakov Institute of Solid State
Physics, Bulgarian Academy of Sciences, Tsarigradsko Chaussée 72, 1784Sofia, Bulgaria
| | - Hassan Chamati
- G Nadjakov Institute of Solid State
Physics, Bulgarian Academy of Sciences, Tsarigradsko Chaussée 72, 1784Sofia, Bulgaria
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8
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Hu ZB, Wang CF, Sha TT, Shi C, Ye L, Ye HY, Song Y, You YM, Zhang Y. An Effective Strategy of Introducing Chirality to Achieve Multifunctionality in Rare-Earth Double Perovskite Ferroelectrics. SMALL METHODS 2022; 6:e2200421. [PMID: 35790109 DOI: 10.1002/smtd.202200421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 05/23/2022] [Indexed: 06/15/2023]
Abstract
The hybrid rare-earth double perovskite (HREDP) system provides great convenience for the construction of multifunctional materials. However, suffering from the high symmetry of their intrinsic structure, HREDPs face the challenges in the realization and optimization of ferroelectric and piezoelectric properties. For the first time, after a systematic investigation of the chirality transformation principle, it is found that the introduction of chirality is an efficient strategy for the targeted construction of multifunctionality, which simultaneously increases the possibility of obtaining multiaxial ferroelectricity and ferroelasticity, and effectively realizes a large piezoelectric response. Moreover, chirality induced ferroelasticity will also achieve excellent magnetic or optical response driven by pressure-sensitive. To verify the feasibility of the above ideas, by using rare-earth ions (Ce3+ ) and suitable chiral organic cations, a new HREDP, (R-N-methyl-3-hydroxylquinuclidinium)2 RbCe(NO3 )6 (R1) is successfully designed, in which ferroelasticity, multiaxial ferroelectricity, satisfactory piezoelectric response, and the pressure-driven single-ion magnetics switch are simultaneously achieved for the first time. This work shows that the induction of chirality and the HREDP system provide an effective strategy and ideal platform for the expansion and optimization of the functions in perovskite ferroelectrics.
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Affiliation(s)
- Zhao-Bo Hu
- Chaotic Matter Science Research Center, Department of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou, 341000, P. R. China
| | - Chang-Feng Wang
- Chaotic Matter Science Research Center, Department of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou, 341000, P. R. China
| | - Tai-Ting Sha
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, 211189, P. R. China
| | - Chao Shi
- Chaotic Matter Science Research Center, Department of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou, 341000, P. R. China
| | - Le Ye
- Chaotic Matter Science Research Center, Department of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou, 341000, P. R. China
| | - Heng-Yun Ye
- Chaotic Matter Science Research Center, Department of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou, 341000, P. R. China
| | - You Song
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Yu-Meng You
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, 211189, P. R. China
| | - Yi Zhang
- Chaotic Matter Science Research Center, Department of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou, 341000, P. R. China
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, 211189, P. R. China
- Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua, 321004, P. R. China
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9
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Agapaki E, Singh MK, Canaj AB, Nichol GS, Schnack J, Brechin EK. A graceful break-up: serendipitous self-assembly of a ferromagnetically coupled [NiII14] wheel. Chem Commun (Camb) 2022; 58:9088-9091. [PMID: 35876803 DOI: 10.1039/d2cc03445j] [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
The complex [NiII14(HL2)12(HCOO)14Cl14(MeOH)(H2O)] describes an aesthetically pleasing wheel displaying ferromagnetic nearest neighbour exchange.
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Affiliation(s)
- Eleftheria Agapaki
- EaStCHEM School of Chemistry, The University of Edinburgh, David Brewster Road, Edinburgh, EH9 3FJ, Scotland, UK.
| | - Mukesh K Singh
- EaStCHEM School of Chemistry, The University of Edinburgh, David Brewster Road, Edinburgh, EH9 3FJ, Scotland, UK.
| | - Angelos B Canaj
- EaStCHEM School of Chemistry, The University of Edinburgh, David Brewster Road, Edinburgh, EH9 3FJ, Scotland, UK.
| | - Gary S Nichol
- EaStCHEM School of Chemistry, The University of Edinburgh, David Brewster Road, Edinburgh, EH9 3FJ, Scotland, UK.
| | - Jürgen Schnack
- Universität Bielefeld, Postfach 100131, D-33501, Bielefeld, Germany.
| | - Euan K Brechin
- EaStCHEM School of Chemistry, The University of Edinburgh, David Brewster Road, Edinburgh, EH9 3FJ, Scotland, UK.
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10
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Ghosh S, Kamilya S, Mehta S, Herchel R, Kiskin M, Veber S, Fedin M, Mondal A. Effect of Ligand Chain Length for Tuning of Molecular Dimensionality and Magnetic Relaxation in Redox Active Cobalt(II) EDOT Complexes (EDOT = 3,4-Ethylenedioxythiophene). Chem Asian J 2022; 17:e202200404. [PMID: 35617522 DOI: 10.1002/asia.202200404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 05/17/2022] [Indexed: 11/07/2022]
Abstract
Four cobalt(II) complexes, [Co(L1)2(NCX)2(MeOH)2] (X = S (1), Se (2)) and {[Co(L2)2(NCX)2]}n (X = S (3), Se (4)) (L1 = 2,5dipyridyl-3,4,-ethylenedioxylthiophene and L2 = 2,5diethynylpyridinyl-3,4-ethylenedioxythiophene), were synthesized by incorporating ethylenedioxythiophene based redox-active luminescence ligands. All these complexes have been well characterized using single-crystal X-ray diffraction analyses, spectroscopic and magnetic investigations. Magneto-structural studies showed that 1 and 2 adopt a mononuclear structure with CoN4O2 octahedral coordination geometry while 3 and 4 have a 2D [4 x 4] rhombic grid coordination networks (CNs) where each cobalt(II) center is in a CoN6 octahedral coordination environment. Static magnetic measurements reveal that all four complexes displayed a high spin (HS) (S = 3/2) state between 2 and 280 K which was further confirmed by X-band and Q-band EPR studies. Remarkably, along with the molecular dimensionality (0D and 2D) the modification in the axial coligands lead to a significant difference in the dynamic magnetic properties of the monomers and CNs at low temperatures. All complexes display slow magnetic relaxation behavior under an external dc magnetic field. For the complexes with NCS- as coligand observed higher energy barrier for spin reversal in comparison to the complexes with NCSe- as coligand, while mononuclear complex 1 exhibited a higher energy barrier than that of CN 3. Theoretical calculations at the DFT and CASSCF level of theory have been performed to get more insight into the electronic structure and magnetic properties of all four complexes.
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Affiliation(s)
- Subrata Ghosh
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C. V. Raman Road, 560012, Bangalore, India
| | - Sujit Kamilya
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C. V. Raman Road, 560012, Bangalore, India
| | - Sakshi Mehta
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C. V. Raman Road, 560012, Bangalore, India
| | - Radovan Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, CZ-771 46, Olomouc, Czech Republic
| | - Mikhail Kiskin
- N. S. Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 31, 119991, Moscow, Russia
| | - Sergey Veber
- International Tomography Center of the Siberian Branch of the Russian Academy of Sciences, Institutskaya Str. 3a, 630090, Novosibirsk, Russia
- Novosibirsk State University, Pirogova Str. 1, 630090, Novosibirsk, Russia
| | - Matvey Fedin
- International Tomography Center of the Siberian Branch of the Russian Academy of Sciences, Institutskaya Str. 3a, 630090, Novosibirsk, Russia
- Novosibirsk State University, Pirogova Str. 1, 630090, Novosibirsk, Russia
| | - Abhishake Mondal
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C. V. Raman Road, 560012, Bangalore, India
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11
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Comba P, Rajaraman G, Sarkar A, Velmurugan G. What controls the magnetic anisotropy in heptacoordinate high-spin cobalt(II) complexes? A theoretical perspective. Dalton Trans 2022; 51:5175-5183. [PMID: 35274660 DOI: 10.1039/d1dt03903b] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The magnetic anisotropy of sixteen seven-coordinate high-spin CoII complexes with O, N, Cl and I donors was investigated with state-of-the-art ab initio CASSCF/NEVPT2 calculations and compared with experimental data. Based on the nature of the equatorial and axial ligands, which were found to tune the zero-field splitting, the complexes were classified into four groups. The experimental zero-field splitting parameters D which, for the various structures are in a range of +30 to +60 cm-1, as well as the g and E values are well reproduced. The investigation of the electronic structure shows that in these pentagonal bipyramidal complexes the donors and symmetry in the equatorial plane play an important role in the values of the axial zero-field splitting parameter D, and breaking of the horizontal plane of symmetry was found to enhance the magnitude of the D value. Although negative values of D are a desired condition for SIMs, many CoII based SIMs with positive zero-field splitting are fundamentally important to understand the nature of magnetic anisotropy, and seven coordinate CoII complexes with a large overall crystal field splitting might provide a way forward in this class of molecules.
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Affiliation(s)
- Peter Comba
- Heidelberg University, Institute of Inorganic Chemistry and Interdisciplinary Center for Scientific Computing, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
| | - Arup Sarkar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
| | - Gunasekaran Velmurugan
- Heidelberg University, Institute of Inorganic Chemistry and Interdisciplinary Center for Scientific Computing, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
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12
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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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Synthesis and spectroscopic interpretations of Co(II), Ni(II) and Cu(II) decxycholate complexes with molecular docking of COVId-19 protease. POLISH JOURNAL OF CHEMICAL TECHNOLOGY 2021. [DOI: 10.2478/pjct-2021-0017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Co(II), Ni(II) and Cu(II) decxycholate complexes are interesting due to their biologically active and deliberate interest in the research due to their coordination properties. The microanalytical ‘elemental analysis’, molar conductivity, (infrared and Raman) spectroscopy, thermal analyses (TGA/DSC), UV-vis spectra, and ESR for copper(II) decxycholate complex investigations were performed in the structural assignments of Co(II), Ni(II) and Cu(II) decxycholate complexes. Reaction of the sodium deoxycholate ligand (C24H39O4Na) with three transition metal ions form the complexes of formulae, [M(C24H39O4)2(H2O)2]. xH2O where M = Co(II), Ni(II) and Cu(II) where x = 2 for Cu(II) and x = 4 in case of M = Co(II) or Ni(II) metal ions. The FTIR spectra of the complexes show that decxycholate molecule is present as bidentate ligand. Molecular docking utilizing to additionally examine the interaction of COVID-19 (6LU7) with different complexes of deoxycholic acid with Co(II), Ni(II) and Cu(II). Furthermore, in the case of Co(II) deoxycholate complex, the probe is surrounded by amino residues Met235, Pro241, Glu240, Pro108, Gln110, Phe294, and Ile152. The probe molecule of Ni(II) deoxycholate complex is sited close to amino acids Tyr126, Tyr239, Leu287, Leu272, and Lys137. For, Cu(II) deoxycholate complex, the residues of amino acids comprise of Pro132, Pro108, Gln110, Gly109, Ile200, Asn203, Val202, His246, Pro293 and Tyr154. The binding energy was determined from the docking reads for Co(II)–6LU7, Ni(II)–6LU7 and Cu(II)–6LU7 deoxycholate compounds were found to be −446.99, −500.52, −398.13 kcal mol−1 individually.
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14
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Sarkar A, Jose R, Ghosh H, Rajaraman G. Record High Magnetic Anisotropy in Three-Coordinate Mn III and Cr II Complexes: A Theoretical Perspective. Inorg Chem 2021; 60:9680-9687. [PMID: 34160217 DOI: 10.1021/acs.inorgchem.1c00978] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ab initio calculations performed in two three-coordinate complexes [Mn{N(SiMe3)2}3] (1) and [K(18-crown-6) (Et2O)2][Cr{N(SiMe3)2}3] (2) reveal record-high magnetic anisotropy with the D values -64 and -15 cm-1, respectively, enlisting d4 ions back in the race for single-ion magnets. A detailed spin-vibrational analysis performed of 1 and 2 suggests dominance under barrier relaxation due to the flexible coordination spheres around the metal ion. Furthermore, several in silico models were constructed by varying the nature of donor atoms based on the X-ray structure of 1 and 2, unveiling much larger anisotropy and robust single-ion magnet (SIM) characteristics for some of the models offering design clues for low-coordinate transition-metal SIMs.
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Affiliation(s)
- Arup Sarkar
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076 Maharashtra, India
| | - Reshma Jose
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076 Maharashtra, India
| | - Harshit Ghosh
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076 Maharashtra, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076 Maharashtra, India
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15
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Legendre CM, Damgaard‐Møller E, Overgaard J, Stalke D. The Quest for Optimal 3 d Orbital Splitting in Tetrahedral Cobalt Single‐Molecule Magnets Featuring Colossal Anisotropy and Hysteresis. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100465] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Christina M. Legendre
- Institut für Anorganische Chemie Georg-August-Universität Göttingen Tammannstraβe 4 37077 Göttingen Germany
| | - Emil Damgaard‐Møller
- Department of Chemistry Aarhus University Langelandsgade 140 Aarhus C 8000 Denmark
| | - Jacob Overgaard
- Department of Chemistry Aarhus University Langelandsgade 140 Aarhus C 8000 Denmark
| | - Dietmar Stalke
- Institut für Anorganische Chemie Georg-August-Universität Göttingen Tammannstraβe 4 37077 Göttingen Germany
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16
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Khurana R, Gupta S, Ali ME. First-Principles Investigations of Magnetic Anisotropy and Spin-Crossover Behavior of Fe(III)-TBP Complexes. J Phys Chem A 2021; 125:2197-2207. [PMID: 33617261 DOI: 10.1021/acs.jpca.1c00022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
With the ongoing effort to obtain mononuclear 3d-transition-metal complexes that manifest slow relaxation of magnetization and, hence, can behave as single-molecule magnets (SMMs), we have modeled 14 Fe(III) complexes based on an experimentally synthesized (PMe3)2FeCl3 complex [J. Am. Chem. Soc. 2017, 139 (46), 16474-16477], by varying the axial ligands with group XV elements (N, P, and As) and equatorial halide ligands from F, Cl, Br, and I. Out of these, nine complexes possess large zero field splitting (ZFS) parameter D in the range of -40 to -60 cm-1. The first-principles investigation of the ground-spin state applying density functional theory (DFT) and wave function-based multiconfigurations methods, e.g., SA-CASSCF/NEVPT2, are found to be quite consistent except for few delicate cases with near-degenerate spin states. In such cases, the hybrid B3LYP functional is found to be biased toward high-spin (HS) state. Altering the percentage of exact exchange admixed in the B3LYP functional leads to intermediate-spin (IS) ground state consistent with the multireference calculations. The origin of large zero field splitting (ZFS) in the Fe(III)-based trigonal bipyramidal (TBP) complexes is investigated. Furthermore, a number of complexes are identified with very small ΔGHS-ISadia. values indicating the possible spin-crossover phenomenon between the bistable spin states.
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Affiliation(s)
- Rishu Khurana
- Institute of Nano Science and Technology, Sector-81, Mohali, Punjab 140306, India
| | - Sameer Gupta
- Institute of Nano Science and Technology, Sector-81, Mohali, Punjab 140306, India
| | - Md Ehesan Ali
- Institute of Nano Science and Technology, Sector-81, Mohali, Punjab 140306, India
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17
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Scott AJ, Vallejo J, Sarkar A, Smythe L, Regincós Martí E, Nichol GS, Klooster WT, Coles SJ, Murrie M, Rajaraman G, Piligkos S, Lusby PJ, Brechin EK. Exploiting host-guest chemistry to manipulate magnetic interactions in metallosupramolecular M 4L 6 tetrahedral cages. Chem Sci 2021; 12:5134-5142. [PMID: 34168772 PMCID: PMC8179613 DOI: 10.1039/d1sc00647a] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Reaction of Ni(OTf)2 with the bisbidentate quaterpyridine ligand L results in the self-assembly of a tetrahedral, paramagnetic cage [NiII4L6]8+. By selectively exchanging the bound triflate from [OTf⊂NiII4L6](OTf)7 (1), we have been able to prepare a series of host–guest complexes that feature an encapsulated paramagnetic tetrahalometallate ion inside this paramagnetic host giving [MIIX4⊂NiII4L6](OTf)6, where MIIX42− = MnCl42− (2), CoCl42− (5), CoBr42− (6), NiCl42− (7), and CuBr42− (8) or [MIIIX4⊂NiII4L6](OTf)7, where MIIIX4− = FeCl4− (3) and FeBr4− (4). Triflate-to-tetrahalometallate exchange occurs in solution and can also be accomplished through single-crystal-to-single-crystal transformations. Host–guest complexes 1–8 all crystallise as homochiral racemates in monoclinic space groups, wherein the four {NiN6} vertexes within a single Ni4L6 unit possess the same Δ or Λ stereochemistry. Magnetic susceptibility and magnetisation data show that the magnetic exchange between metal ions in the host [NiII4] complex, and between the host and the MX4n− guest, are of comparable magnitude and antiferromagnetic in nature. Theoretically derived values for the magnetic exchange are in close agreement with experiment, revealing that large spin densities on the electronegative X-atoms of particular MX4n− guest molecules lead to stronger host–guest magnetic exchange interactions. The tetrahedral [NiII4L6]8+ cage can reversibly bind paramagnetic MX41/2− guests, inducing magnetic exchange interactions between host and guest.![]()
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Affiliation(s)
- Aaron J Scott
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH93FJ UK
| | - Julia Vallejo
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH93FJ UK
| | - Arup Sarkar
- Department of Chemistry, Indian Institute of Technology Bombay Powai Mumbai 400076 India
| | - Lucy Smythe
- WestCHEM, School of Chemistry, University of Glasgow, University Avenue Glasgow G12 8QQ UK
| | - E Regincós Martí
- WestCHEM, School of Chemistry, University of Glasgow, University Avenue Glasgow G12 8QQ UK
| | - Gary S Nichol
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH93FJ UK
| | - Wim T Klooster
- UK National Crystallographic Service, Chemistry, Faculty of Natural and Environmental Sciences, University of Southampton England SO17 1BJ UK
| | - Simon J Coles
- UK National Crystallographic Service, Chemistry, Faculty of Natural and Environmental Sciences, University of Southampton England SO17 1BJ UK
| | - Mark Murrie
- WestCHEM, School of Chemistry, University of Glasgow, University Avenue Glasgow G12 8QQ UK
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay Powai Mumbai 400076 India
| | - Stergios Piligkos
- Department of Chemistry, University of Copenhagen, Universitetsparken 5 2100 Copenhagen Denmark
| | - Paul J Lusby
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH93FJ UK
| | - Euan K Brechin
- EaStCHEM School of Chemistry, The University of Edinburgh David Brewster Road Edinburgh EH93FJ UK
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18
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Sarkar A, Dey S, Rajaraman G. Role of Coordination Number and Geometry in Controlling the Magnetic Anisotropy in Fe II , Co II , and Ni II Single-Ion Magnets. Chemistry 2020; 26:14036-14058. [PMID: 32729641 DOI: 10.1002/chem.202003211] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 12/22/2022]
Abstract
Since the last decade, the focus in the area of single-molecule magnets (SMMs) has been shifting constructively towards the development of single-ion magnets (SIMs) based on transition metals and lanthanides. Although ground-breaking results have been witnessed for DyIII -based SIMs, significant results have also been obtained for some mononuclear transition metal SIMs. Among others, studies based on CoII ion are very prominent as they often exhibit high magnetic anisotropy or zero-field splitting parameters and offer a large barrier height for magnetisation reversal. Although CoII possibly holds the record for having the largest number of zero-field SIMs known for any transition metal ion, controlling the magnetic anisotropy in these systems are is still a challenge. In addition to the modern spectroscopic techniques, theoretical studies, especially ab initio CASSCF/NEVPT2 approaches, have been used to uncover the electronic structure of various CoII SIMs. In this article, with some selected examples, the aim is to showcase how varying the coordination number from two to eight, and the geometry around the CoII centre alters the magnetic anisotropy. This offers some design principles for the experimentalists to target new generation SIMs based on the CoII ion. Additionally, some important FeII /FeIII and NiII complexes exhibiting large magnetic anisotropy and SIM properties are also discussed.
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Affiliation(s)
- Arup Sarkar
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Sourav Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
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19
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Damgaard-Møller E, Krause L, Lassen H, Malaspina LA, Grabowsky S, Bamberger H, McGuire J, Miras HN, Sproules S, Overgaard J. Investigating Complex Magnetic Anisotropy in a Co(II) Molecular Compound: A Charge Density and Correlated Ab Initio Electronic Structure Study. Inorg Chem 2020; 59:13190-13200. [PMID: 32869986 DOI: 10.1021/acs.inorgchem.0c01489] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Understanding magnetic anisotropy and specifically how to tailor it is crucial in the search for high-temperature single-ion magnets. Herein, we investigate the magnetic anisotropy in a six-coordinated cobalt(II) compound that has a complex geometry and distinct triaxial magnetic anisotropy from the perspective of the electronic structure, using electronic spectra, ab initio calculations, and an experimental charge density, of which the latter two provides insight into the d-orbital splitting. The analysis showed that the d-orbital splitting satisfactorily predicted the complex triaxial magnetic anisotropy exhibited by the compound. Furthermore, a novel method to directly compare the ab initio results and the d-orbital populations obtained from the experimental charge density was developed, while a topological analysis of the density provided insights into the metal-ligand bonding. This work thus further establishes the validity of using d-orbitals for predicting magnetic anisotropy in transition metal compounds while also pointing out the need for a more frequent usage of the term triaxial anisotropy in the field of single-molecule magnetism.
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Affiliation(s)
- Emil Damgaard-Møller
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Lennard Krause
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Helene Lassen
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Lorraine A Malaspina
- Department 2-Biology/Chemistry, University of Bremen, Leobener Str. 3, 28359 Bremen, Germany
| | - Simon Grabowsky
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Heiko Bamberger
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Jake McGuire
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ, Glasgow, United Kingdom
| | - Haralampos N Miras
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ, Glasgow, United Kingdom
| | - Stephen Sproules
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ, Glasgow, United Kingdom
| | - Jacob Overgaard
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
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20
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Putting the Squeeze on Molecule-Based Magnets: Exploiting Pressure to Develop Magneto-Structural Correlations in Paramagnetic Coordination Compounds. MAGNETOCHEMISTRY 2020. [DOI: 10.3390/magnetochemistry6030032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The cornerstone of molecular magnetism is a detailed understanding of the relationship between structure and magnetic behaviour, i.e., the development of magneto-structural correlations. Traditionally, the synthetic chemist approaches this challenge by making multiple compounds that share a similar magnetic core but differ in peripheral ligation. Changes in the ligand framework induce changes in the bond angles and distances around the metal ions, which are manifested in changes to magnetic susceptibility and magnetisation data. This approach requires the synthesis of a series of different ligands and assumes that the chemical/electronic nature of the ligands and their coordination to the metal, the nature and number of counter ions and how they are positioned in the crystal lattice, and the molecular and crystallographic symmetry have no effect on the measured magnetic properties. In short, the assumption is that everything outwith the magnetic core is inconsequential, which is a huge oversimplification. The ideal scenario would be to have the same complex available in multiple structural conformations, and this is something that can be achieved through the application of external hydrostatic pressure, correlating structural changes observed through high-pressure single crystal X-ray crystallography with changes observed in high-pressure magnetometry, in tandem with high-pressure inelastic neutron scattering (INS), high-pressure electron paramagnetic resonance (EPR) spectroscopy, and high-pressure absorption/emission/Raman spectroscopy. In this review, which summarises our work in this area over the last 15 years, we show that the application of pressure to molecule-based magnets can (reversibly) (1) lead to changes in bond angles, distances, and Jahn–Teller orientations; (2) break and form bonds; (3) induce polymerisation/depolymerisation; (4) enforce multiple phase transitions; (5) instigate piezochromism; (6) change the magnitude and sign of pairwise exchange interactions and magnetic anisotropy, and (7) lead to significant increases in magnetic ordering temperatures.
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21
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Jankowski R, Reczyński M, Chorazy S, Zychowicz M, Arczyński M, Kozieł M, Ogorzały K, Makowski W, Pinkowicz D, Sieklucka B. Guest-Dependent Pressure-Induced Spin Crossover in Fe II 4 [M IV (CN) 8 ] 2 (M=Mo, W) Cluster-Based Material Showing Persistent Solvent-Driven Structural Transformations. Chemistry 2020; 26:11187-11198. [PMID: 32227503 DOI: 10.1002/chem.202000146] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Indexed: 01/28/2023]
Abstract
Discrete molecular species that can perform certain functions in response to multiple external stimuli constitute a special class of multifunctional molecular materials called smart molecules. Herein, cyanido-bridged coordination clusters {[FeII (2-pyrpy)2 ]4 [MIV (CN)8 ]2 }⋅4 MeOH⋅6 H2 O (M=Mo (1 solv), M=W (2 solv) and 2-pyrpy=2-(1-pyrazolyl)pyridine are presented, which show persistent solvent driven single-crystal-to-single-crystal transformations upon sorption/desorption of water and methanol molecules. Three full desolvation-resolvation cycles with the concomitant change of the host molecules do not damage the single crystals. More importantly, the Fe4 M2 molecules constitute a unique example where the presence of the guests directly affects the pressure-induced thermal spin crossover (SCO) phenomenon occurring at the FeII centres. The hydrated phases show a partial SCO with approximately two out-of-four FeII centres undergoing a gradual thermal SCO at 1 GPa, while in the anhydrous form the pressure-induced SCO effect is almost quenched with only 15 % of the FeII centres undergoing high-spin to low-spin transition at 1 GPa.
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Affiliation(s)
- Robert Jankowski
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30387, Krakow, Poland
| | - Mateusz Reczyński
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30387, Krakow, Poland
| | - Szymon Chorazy
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30387, Krakow, Poland
| | - Mikołaj Zychowicz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30387, Krakow, Poland
| | - Mirosław Arczyński
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30387, Krakow, Poland
| | - Marcin Kozieł
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30387, Krakow, Poland
| | - Karolina Ogorzały
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30387, Krakow, Poland
| | - Wacław Makowski
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30387, Krakow, Poland
| | - Dawid Pinkowicz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30387, Krakow, Poland
| | - Barbara Sieklucka
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30387, Krakow, Poland
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22
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Ghosh S, Kamilya S, Das M, Mehta S, Boulon ME, Nemec I, Rouzières M, Herchel R, Mondal A. Effect of Coordination Geometry on Magnetic Properties in a Series of Cobalt(II) Complexes and Structural Transformation in Mother Liquor. Inorg Chem 2020; 59:7067-7081. [DOI: 10.1021/acs.inorgchem.0c00538] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Subrata Ghosh
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C. V. Raman Road, Bangalore 560012, India
| | - Sujit Kamilya
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C. V. Raman Road, Bangalore 560012, India
| | - Mayurika Das
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C. V. Raman Road, Bangalore 560012, India
| | - Sakshi Mehta
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C. V. Raman Road, Bangalore 560012, India
| | - Marie-Emmanuelle Boulon
- Photon Science Institute, Alan Turing Building, office 3.315, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Ivan Nemec
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, CZ-771 46 Olomouc, Czech Republic
- Central European Institute of Technology, CEITEC BUT, Technická 3058/10, 61600 Brno, Czech Republic
| | - Mathieu Rouzières
- Univ. Bordeaux, CNRS, Centre de Recherche Paul Pascal, CRPP, UMR 5031, 33600 Pessac, France
| | - Radovan Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, CZ-771 46 Olomouc, Czech Republic
| | - Abhishake Mondal
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C. V. Raman Road, Bangalore 560012, India
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23
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Thiel AM, Damgaard-Møller E, Overgaard J. High-Pressure Crystallography as a Guide in the Design of Single-Molecule Magnets. Inorg Chem 2020; 59:1682-1691. [PMID: 31944683 DOI: 10.1021/acs.inorgchem.9b02794] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Single-molecule magnet materials owe their function to the presence of significant magnetic anisotropy, which arises from the interplay between the ligand field and spin-orbit coupling, and this is responsible for setting up an energy barrier for magnetic relaxation. Therefore, chemical control of magnetic anisotropy is a central challenge in the quest to synthesize new molecular nanomagnets with improved properties. There have been several reports of design principles targeting such control; however, these principles rely on idealized geometries, which are rarely obtained in crystal structures. Here, we present the results of high-pressure single-crystal diffraction on the single-ion magnet, Co(SPh)4(PPh4)2, in the pressure range of 0-9.2 GPa. Upon pressurization a sequence of small geometrical distortions of the central CoS4 moeity are observed, enabling a thorough analysis of the magneto-structural correlations. The magneto-structural correlations are investigated by theoretical analyses of the pressure-dependent experimental molecular structures. We observed a significant increase in the magnitude of the zero-field splitting parameter D, from -54.6 cm-1 to -89.7 cm-1, which was clearly explained from the reduction of the energy difference between the essential dxy and dx2-y2 orbitals, and structurally assigned to the change of an angle of compression of the CoS4 moeity.
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Affiliation(s)
- Andreas M Thiel
- Department of Chemistry , Aarhus University , Langelandsgade 140 , DK-8000 Aarhus C , Denmark
| | - Emil Damgaard-Møller
- Department of Chemistry , Aarhus University , Langelandsgade 140 , DK-8000 Aarhus C , Denmark
| | - Jacob Overgaard
- Department of Chemistry , Aarhus University , Langelandsgade 140 , DK-8000 Aarhus C , Denmark
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24
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Castro-Alvarez A, Gil Y, Llanos L, Aravena D. High performance single-molecule magnets, Orbach or Raman relaxation suppression? Inorg Chem Front 2020. [DOI: 10.1039/d0qi00487a] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Relaxation mechanisms limiting the blocking temperature for high-performance single molecule magnets (SMMs) are investigated. Best SMMs are limited by the exponential regime. Current ab initio methods can yield accurate estimations for this limit.
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Affiliation(s)
- Alejandro Castro-Alvarez
- Departamento de Química de los Materiales
- Facultad de Química y Biología
- Universidad de Santiago de Chile
- Santiago
- Chile
| | - Yolimar Gil
- Departamento de Química Inorgánica y Analítica
- Facultad de Ciencias Químicas y Farmacéuticas
- Universidad de Chile
- Santiago
- Chile
| | - Leonel Llanos
- Departamento de Química de los Materiales
- Facultad de Química y Biología
- Universidad de Santiago de Chile
- Santiago
- Chile
| | - Daniel Aravena
- Departamento de Química de los Materiales
- Facultad de Química y Biología
- Universidad de Santiago de Chile
- Santiago
- Chile
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25
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Hay MA, Sarkar A, Craig GA, Marriott KER, Wilson C, Rajaraman G, Murrie M. A large axial magnetic anisotropy in trigonal bipyramidal Fe(ii). Chem Commun (Camb) 2020; 56:6826-6829. [DOI: 10.1039/d0cc02382e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Minimising geometric distortion in the first coordination sphere generates a large axial magnetic anisotropy in trigonal bipyramidal Fe(ii) and rare slow magnetic relaxation.
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Affiliation(s)
- Moya A. Hay
- School of Chemistry
- University of Glasgow
- Glasgow
- UK
| | - Arup Sarkar
- Department of Chemistry
- Institute of Technology Bombay
- Mumbai
- India
| | | | | | | | | | - Mark Murrie
- School of Chemistry
- University of Glasgow
- Glasgow
- UK
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26
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Harriman KLM, Murillo J, Suturina EA, Fortier S, Murugesu M. Relaxation dynamics in see-saw shaped Dy(iii) single-molecule magnets. Inorg Chem Front 2020. [DOI: 10.1039/d0qi01007c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Unusual see-saw shaped Dy(iii) single-molecule magnets, [K(DME)n][LArDy(X)2] (LAr = {C6H4[(2,6-iPrC6H3)NC6H4]2}2−), X = Cl (1) and X = I (2) were synthesized and display high effective energy barriers (Ueff = 1278–1334 K) in zero field.
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Affiliation(s)
- Katie L. M. Harriman
- Department of Chemistry and Biomolecular Sciences
- University of Ottawa
- Ottawa
- Canada
| | - Jesse Murillo
- Department of Chemistry and Biochemistry
- University of Texas at El Paso
- El Paso
- USA
| | | | - Skye Fortier
- Department of Chemistry and Biochemistry
- University of Texas at El Paso
- El Paso
- USA
| | - Muralee Murugesu
- Department of Chemistry and Biomolecular Sciences
- University of Ottawa
- Ottawa
- Canada
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27
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Norre MS, Gao C, Dey S, Gupta SK, Borah A, Murugavel R, Rajaraman G, Overgaard J. High-Pressure Crystallographic and Magnetic Studies of Pseudo-D5h Symmetric Dy(III) and Ho(III) Single-Molecule Magnets. Inorg Chem 2019; 59:717-729. [DOI: 10.1021/acs.inorgchem.9b02962] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Marie S. Norre
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Chen Gao
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Sourav Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Sandeep K. Gupta
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Aditya Borah
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Ramaswamy Murugavel
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Jacob Overgaard
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
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28
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Singh MK, Shukla P, Khatua M, Rajaraman G. A Design Criteria to Achieve Giant Ising-Type Anisotropy in Co II -Encapsulated Metallofullerenes. Chemistry 2019; 26:464-477. [PMID: 31506987 DOI: 10.1002/chem.201903618] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/05/2019] [Indexed: 11/10/2022]
Abstract
Discovery of permanent magnetisation in molecules just like in hard magnets decades ago led to the proposal of utilising these molecules for information storage devices and also as Q-bits in quantum computing. A significant breakthrough with a blocking temperature as high as 80 K has been recently reported for lanthanocene complexes. While enhancing the blocking temperature further remains one of the primary challenges, obtaining molecules that are suitable for the fabrication of the devices sets the bar very high in this area. Encouraged by the fact that our earlier predictions of potential single-molecule magnets (SMMs) in lanthanide-containing endohedral fullerenes have been verified, here we set out to undertake a comprehensive study on CoII -ion-encapsulated fullerene as potential SMMs. To study this class of molecules, we have utilised an array of theoretical methods ranging from density functional to ab initio CASSCF/NEVPT2 methods for obtaining reliable estimate of zero-field splitting parameters D and E. Additionally, we have also employed, for the first time a combination of molecular dynamics based on DFT methods coupled with CASSCF/NEVPT2 methods to seek the role of conformational isomers in the relaxation of magnetisation. Particularly, we have studied, Co@C28 , Co@C38 and Co@C48 cages and their isomers as potential target molecules that could yield substantial magnetic anisotropy. Our calculations categorically reveal a very large Ising anisotropy in this class of molecules, with Co@C48 cages predicted to yield D values as high as -127 cm-1 . Our calculations on the smaller cages reveal the free movement of CoII ion inside the cage, leading to the likely scenario of faster relaxation of magnetisation. However, larger fullerene cages were found to solve this issue. Further models with incorporating units such as {CoOZn}, {CoScZnN} inside larger fullerenes yield axial zero-field splitting values as high as -200 cm-1 with negligible E/D values. As these units represent a strong axiality coupled with a viable way to obtain air-stable low-coordinate CoII complexes, this opens up a new paradigm in the search of SMMs in this class of molecules.
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Affiliation(s)
- Mukesh Kumar Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Pratima Shukla
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Munmun Khatua
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
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29
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Sarkar A, Tewary S, Sinkar S, Rajaraman G. Magnetic Anisotropy in Co
II
X
4
(X=O, S, Se) Single‐Ion Magnets: Role of Structural Distortions versus Heavy Atom Effect. Chem Asian J 2019; 14:4696-4704. [DOI: 10.1002/asia.201901140] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/04/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Arup Sarkar
- Department of ChemistryIndian Institute of Technology Bombay Powai Mumbai 400076 India
| | - Subrata Tewary
- Department of ChemistryIndian Institute of Technology Bombay Powai Mumbai 400076 India
- Current address: RIKEN Center for Computational Science 7-1-26, Minatojima-minami-machi Chuo-ku Kobe 650-0047 Japan
| | - Shwetali Sinkar
- Department of ChemistryIndian Institute of Technology Bombay Powai Mumbai 400076 India
| | - Gopalan Rajaraman
- Department of ChemistryIndian Institute of Technology Bombay Powai Mumbai 400076 India
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30
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Acharya J, Swain A, Chakraborty A, Kumar V, Kumar P, Gonzalez JF, Cador O, Pointillart F, Rajaraman G, Chandrasekhar V. Slow Magnetic Relaxation in Dinuclear Co IIY III Complexes. Inorg Chem 2019; 58:10725-10735. [PMID: 31368683 DOI: 10.1021/acs.inorgchem.9b00864] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Four new dinuclear complexes, [Co(μ-L)(μ-CCl3COO)Y(NO3)2]·2CHCl3·CH3CN·2H2O (1), [Co(μ-L)(μ-CH3COO)Y(NO3)2]·CH3CN (2), [Co(μ-L)(μ-PhCOO)Y(NO3)2]·3CH3CN·2H2O (3), and [Co(μ-L)(μ-tBuCOO)Y(NO3)2]·CHCl3·2H2O (4), having a CoIIYIII core, have been synthesized by employing a ferrocene based compartmental ligand which was synthesized by the reaction of diacetyl ferrocene with hydrazine hydrate followed by a condensation reaction with o-vanillin. A general synthetic protocol was employed to synthesize complexes 1-4, where the metallic core was kept the same with changing the bridging carboxylate groups. In all the complexes, the main structural motif is kept similar by only slightly varying the substitution on the bridging acetate groups. This variation has resulted in a small but subtle influence on the magnetic relaxation of all these four compounds. Ab initio CASSCF/NEVPT2 calculations were carried out to assess the effect of the different substitutions of the bridging ligands on the magnetic anisotropy parameters and on orbital arrangements. Ab initio calculations yield a very large positive D value, which is consistent with the geometry around the CoII ion and easy plane anisotropy (gxx, gyy > gzz), with the order of the calculated D in the range of 72.4 to 91.7 cm-1 being estimated in this set of complexes. To ascertain the sign of zero-field splitting in these complexes, EPR spectra were recorded, which support the sign of D values estimated from ab initio calculations.
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Affiliation(s)
- Joydev Acharya
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur - 208016 , India
| | - Abinash Swain
- Department of Chemistry , Indian Institute of Technology Bombay , Powai , Mumbai - 400 076 , India
| | - Amit Chakraborty
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur - 208016 , India.,Tata Institute of Fundamental Research , Gopanpally , Hyderabad - 500107 , India
| | - Vierandra Kumar
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur - 208016 , India
| | - Pawan Kumar
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur - 208016 , India
| | - Jessica Flores Gonzalez
- Institut des Sciences Chimiques de Rennes , UMR 6226 CNRS-Université de Rennes 1 , 263 Avenue du Général Leclerc , 35042 Rennes Cedex , France
| | - Olivier Cador
- Institut des Sciences Chimiques de Rennes , UMR 6226 CNRS-Université de Rennes 1 , 263 Avenue du Général Leclerc , 35042 Rennes Cedex , France
| | - Fabrice Pointillart
- Institut des Sciences Chimiques de Rennes , UMR 6226 CNRS-Université de Rennes 1 , 263 Avenue du Général Leclerc , 35042 Rennes Cedex , France
| | - Gopalan Rajaraman
- Department of Chemistry , Indian Institute of Technology Bombay , Powai , Mumbai - 400 076 , India
| | - Vadapalli Chandrasekhar
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur - 208016 , India.,Tata Institute of Fundamental Research , Gopanpally , Hyderabad - 500107 , India
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31
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Hay MA, Sarkar A, Marriott KER, Wilson C, Rajaraman G, Murrie M. Investigation of the magnetic anisotropy in a series of trigonal bipyramidal Mn(ii) complexes. Dalton Trans 2019; 48:15480-15486. [PMID: 31282505 DOI: 10.1039/c9dt02187f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Understanding how the magnetic anisotropy in simple coordination complexes can be manipulated is instrumental to the development of single-molecule magnets (SMMs). Clear strategies can then be designed to control both the axial and transverse contributions to the magnetic anisotropy in such compounds, and allow them to reach their full potential. Here we show a strategy for boosting the magnetic anisotropy in a series of trigonal bipyramidal Mn(ii) complexes - [MnCl3(HDABCO)(DABCO)] (1), [MnCl3(MDABCO)2]·[ClO4] (2), and [MnCl3(H2O)(MDABCO)] (3). These have been successfully synthesised using the monodentate [DABCO] and [MDABCO]+ ligands. Through static (DC) magnetic measurements and detailed theoretical investigation using ab initio methods, the magnetic anisotropy of each system has been studied. The calculations reveal that the rhombic zero-field splitting (ZFS) term (E) can be tuned as the symmetry around the Mn(ii) ion is changed. Furthermore, an in silico investigation reveals a strategy to increase the axial ZFS parameter (D) of trigonal bipyramidal Mn(ii) by an order of magnitude.
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Affiliation(s)
- Moya A Hay
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - Arup Sarkar
- Department of Chemistry, Institute of Technology Bombay, Powai, Mumbai, Maharashtra 400 076, India.
| | - Katie E R Marriott
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - Claire Wilson
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - Gopalan Rajaraman
- Department of Chemistry, Institute of Technology Bombay, Powai, Mumbai, Maharashtra 400 076, India.
| | - Mark Murrie
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK.
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32
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How to Quench Ferromagnetic Ordering in a CN-Bridged Ni(II)-Nb(IV) Molecular Magnet? A Combined High-Pressure Single-Crystal X-Ray Diffraction and Magnetic Study. MAGNETOCHEMISTRY 2019. [DOI: 10.3390/magnetochemistry5020033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
High-pressure (HP) structural and magnetic properties of a magnetic coordination polymer {[NiII(pyrazole)4]2[NbIV(CN)8]·4H2O}n (Ni2Nb) are presented, discussed and compared with its two previously reported analogs {[MnII(pyrazole)4]2[NbIV(CN)8]·4H2O}n (Mn2Nb) and {[FeII(pyrazole)4]2[NbIV(CN)8]·4H2O}n (Fe2Nb). Ni2Nb shows a significant decrease of the long-range ferromagnetic ordering under high pressure when compared to Mn2Nb, where the pressure enhances the Tc (magnetic ordering temperature), or to Fe2Nb exhibiting a pressure-induced spin crossover. The different HP magnetic responses of the three compounds were rationalized and correlated with the structural models as determined by single-crystal X-ray diffraction.
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33
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Singh MK, Rajaraman G. Theoretical Studies on Hexanuclear [M 3(μ 3-O/OH)] 2 (M = Fe(III), Mn(III), and Ni(II)) Clusters: Magnetic Exchange, Magnetic Anisotropy, and Magneto-Structural Correlations. Inorg Chem 2019; 58:3175-3188. [PMID: 30741554 DOI: 10.1021/acs.inorgchem.8b03257] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Controlling spin Hamiltonian parameters such as magnetic exchange and magnetic anisotropy of polynuclear clusters is of great interest in the area of single molecule magnets (SMMs). Among large polynuclear clusters, hexanuclear clusters offer the best compromise in terms of size as they are often rigid, solution stable, and chemically amenable. The {M6O2} core is one of the common architectures known for many hexanuclear clusters and generally reported to possess a diamagnetic ST = 0 spin ground state, barring a few exceptions. In these clusters, there are several open questions that are poorly understood: (a) What controls the nature of magnetic exchange, which in turn dictates the ground state spin values? (b) For clusters possessing a nonzero spin ground state, what dictates the magnetic anisotropy? Here, using density functional methods, we have attempted to shed light on these two question by evaluating the exchange coupling constants in [Fe6IIIO2(OH)2{(C4N2H2SMe)2C(OH)O}2( tBuCO2)10] (1), [Fe6III(O)2(O2CH2)(O2CCH2 tBu)12(py)2] (2), [Fe6III(O2)(O)2(O2CCMe3)12(py)2] (3), [FeIII6O3(O2CMe)9(OEt)2(bpy)2]ClO4 (4), [MnIII6O2(O2CH2)(O2CPe t)11(HO2CPe t)2(O2CMe)] (5), and [NiII6(OH)4(O2C tBu)8( tBuCO2H)4] (6) complexes. We have estimated all the eight near-neighbor exchange coupling constants in these clusters. Our calculations not only agree with the experimental results but also offer insight on the origin of the spin ground state. Extensive magneto-structural correlations developed by varying M-O-M angles and M-O distances reveal that J values are extremely sensitive to small structural distortions. Correlations developed indicate that both the parameters are important for Fe(III), but for Mn(III) and Ni(II), the angles were found to play a dominant role. Quite interestingly, the computed zero-field splitting parameter D S=5 of complex 1 reveals that the exchange contribution to the anisotropy controls the sign of the ground state D value-an observation which differs from the general perception that the ground state D is controlled by the single-ion zero-field splitting parameter.
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Affiliation(s)
- Mukesh Kumar Singh
- Department of Chemistry , Indian Institute of Technology Bombay , Powai, Mumbai , Maharashtra , India - 400076
| | - Gopalan Rajaraman
- Department of Chemistry , Indian Institute of Technology Bombay , Powai, Mumbai , Maharashtra , India - 400076
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34
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Yong W, Lekin K, Bauer RPC, Tse JS, Desgreniers S, Secco RA, Hirao N, Oakley RT. Pancakes under Pressure: A Case Study on Isostructural Dithia- and Diselenadiazolyl Radical Dimers. Inorg Chem 2019; 58:3550-3557. [PMID: 30785745 DOI: 10.1021/acs.inorgchem.9b00142] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The isostructural dimers of the 1,4-phenylene-bridged bis-1,2,3,5-dithia- and bis-1,2,3,5-diselenadiazolyl diradicals 1,4-S/Se are small band gap semiconductors. The response of their molecular and solid state electronic structures to pressure has been explored over the range 0-10 GPa. The crystal structures, which consist of cofacially aligned (pancake) π-dimers packed into herringbone arrays, experience a continuous, near-isotropic compression. While the intramolecular covalent E-E (E = S/Se) bonds remain relatively unchanged with pressurization, the intradimer E···E separations are significantly shortened. Molecular and band electronic structure calculations using density functional theory methods indicate that compression of the π-dimers leads to a widening of the gap Δ E between the highest occupied and lowest unoccupied molecular orbitals of the dimer, an effect that offsets the expected decrease in the valence-to-conduction band gap Eg occasioned by pressure-induced spreading of the valence and conduction bands. Consistent with the predicted consequences of this competition between intra- and interdimer interactions, variable temperature high pressure conductivity measurements reveal at best an order-of-magnitude increase in conductivity with pressure for the two compounds over the pressure range 0-10 GPa. While a small reduction in the thermal activation energy Eact with increasing pressure is observed, extrapolation of the rate of decrease suggests a projected onset of metallization ( Eact ≈ 0) in excess of 20 GPa.
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Affiliation(s)
- Wenjun Yong
- Department of Earth Sciences , University of Western Ontario , London , Ontario N6A 5B7 , Canada
| | - Kristina Lekin
- Department of Chemistry , University of Waterloo , Waterloo , Ontario N2L 3G1 , Canada
| | - Robert P C Bauer
- Department of Physics , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada
| | - John S Tse
- Department of Physics , University of Saskatchewan , Saskatoon , Saskatchewan S7N 5E2 , Canada
| | - Serge Desgreniers
- Department of Physics , University of Ottawa , Ottawa , Ontario K1N 6N5 , Canada
| | - Richard A Secco
- Department of Earth Sciences , University of Western Ontario , London , Ontario N6A 5B7 , Canada
| | - Naohisa Hirao
- Materials Science Division , Japan Synchrotron Radiation Research Institute , SPring-8, Sayo , Hyogo 679-5198 , Japan
| | - Richard T Oakley
- Department of Chemistry , University of Waterloo , Waterloo , Ontario N2L 3G1 , Canada
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35
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Luo X, Tsai D, Gu M, Hong M. Extraordinary optical fields in nanostructures: from sub-diffraction-limited optics to sensing and energy conversion. Chem Soc Rev 2019; 48:2458-2494. [PMID: 30839959 DOI: 10.1039/c8cs00864g] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Along with the rapid development of micro/nanofabrication technology, the past few decades have seen the flourishing emergence of subwavelength-structured materials and interfaces for optical field engineering at the nanoscale. Three remarkable properties associated with these subwavelength-structured materials are the squeezed optical fields beyond the diffraction limit, gradient optical fields in the subwavelength scale, and enhanced optical fields that are orders of magnitude greater than the incident field. These engineered optical fields have inspired fundamental and practical advances in both engineering optics and modern chemistry. The first property is the basis of sub-diffraction-limited imaging, lithography, and dense data storage. The second property has led to the emergence of a couple of thin and planar functional optical devices with a reduced footprint. The third one causes enhanced radiation (e.g., fluorescence), scattering (e.g., Raman scattering), and absorption (e.g., infrared absorption and circular dichroism), offering a unique platform for single-molecule-level biochemical sensing, and high-efficiency chemical reaction and energy conversion. In this review, we summarize recent advances in subwavelength-structured materials that bear extraordinary squeezed, gradient, and enhanced optical fields, with a particular emphasis on their optical and chemical applications. Finally, challenges and outlooks in this promising field are discussed.
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Affiliation(s)
- Xiangang Luo
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, 610209, China.
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36
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Zakharov BA, Boldyreva EV. High pressure: a complementary tool for probing solid-state processes. CrystEngComm 2019. [DOI: 10.1039/c8ce01391h] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
High pressure offers insight into the mechanisms of a wide range of solid-state phenomena occurring under atmospheric pressure conditions.
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Affiliation(s)
- Boris A. Zakharov
- Boreskov Institute of Catalysis
- Siberian Branch of the Russian Academy of Sciences
- Novosibirsk
- Russian Federation
- Novosibirsk State University
| | - Elena V. Boldyreva
- Boreskov Institute of Catalysis
- Siberian Branch of the Russian Academy of Sciences
- Novosibirsk
- Russian Federation
- Novosibirsk State University
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37
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Schulte KA, Vignesh KR, Dunbar KR. Effects of coordination sphere on unusually large zero field splitting and slow magnetic relaxation in trigonally symmetric molecules. Chem Sci 2018; 9:9018-9026. [PMID: 30647894 PMCID: PMC6301199 DOI: 10.1039/c8sc02820f] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/15/2018] [Indexed: 01/29/2023] Open
Abstract
Geometric control in mononuclear complexes has come to the forefront in the field of molecular magnets due to its profound effects on relaxation pathways and blocking temperature in single molecule magnets (SMMs). Herein we report the synthesis and magnetic characterization of six trigonally symmetric, divalent Fe, Co, and Ni molecules, with the rigid geometry enforced via the use of the tris-anionic, tetradentate ligand MST (N,N',N''-[2,2',2''-nitrilotris-(ethane-2,1-diyl)]tris(2,4,6-trimethylbenzenesulfonamide)). A systematic study on the effect of converting between trigonal monopyramidal complexes, (Me4N)[M(MST)], and trigonal bipyramidal complexes, (Me4N)[M(MST)(OH2)] was conducted experimentally and computationally. It was found that (Me4N)[Ni(MST)] exhibits a very large, near record zero-field splitting parameter (D) value of -434 cm-1, owing to an extremely low lying first excited state. The trigonal monopyramidal cobalt and iron complexes exhibit slow magnetic relaxation under applied fields, resulting in barriers of 45 K and 63.9 K respectively. Coordination of a single water molecule in the open axial site of the trigonal monopyramidal complexes exerts drastic dampening effects on the D value as well as slow relaxation. Computations reveal that coordination of water rotates the D zz axis away from the C 3 axis of symmetry resulting in a smaller D value. The aquo species (Me4N)[Co(MST)(OH2)] also exhibits magnetic relaxation under an applied field, but the barrier is reduced to 9.9 K. Water coordination totally quenches the magnetic behavior in the iron complex, and reduces the D value for nickel to -185 cm-1. These results showcase the drastic effect that a small change in the coordination environment can have on magnetic behavior, as well as that trigonal monopyramidal geometry can lead to near record D values.
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Affiliation(s)
- Kelsey A Schulte
- Department of Chemistry , Texas A&M University , College Station , Texas 77843 , USA .
| | - Kuduva R Vignesh
- Department of Chemistry , Texas A&M University , College Station , Texas 77843 , USA .
| | - Kim R Dunbar
- Department of Chemistry , Texas A&M University , College Station , Texas 77843 , USA .
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38
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Zhang X, Su F, Guo W, Sañudo EC, Liu C. An Unusual Ln
III
‐Based Metal‐Organic Framework with Dinuclear Nodes Exhibiting Single‐Molecular Magnet Behavior. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201801183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Xue‐Jing Zhang
- Henan Provincial Key Laboratory of Surface & Interface Science Secció de Química Inorgànica i Institut de Nanociència i Nanotecnologia Zhengzhou University of Light Industry 450002 Zhengzhou P. R. China
| | - Fang‐Zhe Su
- Henan Provincial Key Laboratory of Surface & Interface Science Secció de Química Inorgànica i Institut de Nanociència i Nanotecnologia Zhengzhou University of Light Industry 450002 Zhengzhou P. R. China
| | - Wan‐Ying Guo
- Henan Provincial Key Laboratory of Surface & Interface Science Secció de Química Inorgànica i Institut de Nanociència i Nanotecnologia Zhengzhou University of Light Industry 450002 Zhengzhou P. R. China
| | - E. Carolina Sañudo
- Departament de Química Inorgànica i Orgànica Secció de Química Inorgànica i Institut de Nanociència i Nanotecnologia Universitat de Barcelona C/Martí i Franqués 1‐11 08028 Barcelona SPAIN
| | - Chun‐Sen Liu
- Henan Provincial Key Laboratory of Surface & Interface Science Secció de Química Inorgànica i Institut de Nanociència i Nanotecnologia Zhengzhou University of Light Industry 450002 Zhengzhou P. R. China
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39
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Chen L, Song J, Zhao W, Yi G, Zhou Z, Yuan A, Song Y, Wang Z, Ouyang ZW. A mononuclear five-coordinate Co(ii) single molecule magnet with a spin crossover between the S = 1/2 and 3/2 states. Dalton Trans 2018; 47:16596-16602. [PMID: 30417917 DOI: 10.1039/c8dt03783c] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Although a great number of single-ion magnets (SIMs) and spin-crossover (SCO) compounds have been discovered, multifunctional materials with the combination of SCO and SIM properties are extremely scarce. Here magnetic studies have been carried out for a mononuclear, five-coordinate cobalt(ii) complex [Co(3,4-lut)4Br]Br (1) with square pyramidal geometry. Direct-current magnetic measurement confirms the spin transition between the S = 1/2 and 3/2 states in the range of 150-290 K with a small hysteresis loop. Frequency- and temperature-dependent alternating-current magnetic susceptibility reveals slow magnetization relaxation under an applied dc field of 3000 Oe. The work here presents the first instance of the five-coordinate mononuclear cobalt(ii)-based SIM exhibiting the thermally induced complete SCO.
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Affiliation(s)
- Lei Chen
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
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40
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Dey A, Kalita P, Chandrasekhar V. Lanthanide(III)-Based Single-Ion Magnets. ACS OMEGA 2018; 3:9462-9475. [PMID: 31459081 PMCID: PMC6644820 DOI: 10.1021/acsomega.8b01204] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 08/03/2018] [Indexed: 05/27/2023]
Abstract
Mononuclear lanthanide-based single-ion magnets (SIMs) are known since 2003 with the discovery of SIM properties in a bis-(phthalocyaninato)lanthanide complex. A recent report on [Dy(Cpttt)2][BC6F5] indicating that it exhibits the highest known blocking temperature (60 K) has spurred fresh interest in this area. In this article, we discuss about the various requirements of lanthanide-based SIMs along with representative examples. Specifically, we describe the complexes whose coordination numbers vary from 2 to 8. We also discuss the representative examples of organometallic lanthanide complexes that can function as molecular magnets.
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Affiliation(s)
- Atanu Dey
- Tata
Institute of Fundamental Research Hyderabad, Hyderabad 500107, India
| | - Pankaj Kalita
- School
of Chemical Sciences, National Institute of Science Education and
Research, HBNI, Bhubaneswar 752050, India
| | - Vadapalli Chandrasekhar
- Tata
Institute of Fundamental Research Hyderabad, Hyderabad 500107, India
- Department
of Chemistry, Indian Institute of Technology
Kanpur, Kanpur 208016, India
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41
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Pandey B, Ray K, Rajaraman G. Structure, Bonding, Reactivity and Spectral Features of Putative NiIII
=O Species: A Theoretical Perspective. Z Anorg Allg Chem 2018. [DOI: 10.1002/zaac.201800122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Bhawana Pandey
- Department of Chemistry; Indian Institute of Technology Bombay; 400 076 Powai India
| | - Kallol Ray
- Institut fár Chemie; Humboldt-Universität zu Berlin; Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Gopalan Rajaraman
- Department of Chemistry; Indian Institute of Technology Bombay; 400 076 Powai India
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Rigamonti L, Bridonneau N, Poneti G, Tesi L, Sorace L, Pinkowicz D, Jover J, Ruiz E, Sessoli R, Cornia A. A Pseudo-Octahedral Cobalt(II) Complex with Bispyrazolylpyridine Ligands Acting as a Zero-Field Single-Molecule Magnet with Easy Axis Anisotropy. Chemistry 2018; 24:8857-8868. [PMID: 29655240 DOI: 10.1002/chem.201801026] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Indexed: 01/31/2023]
Abstract
The homoleptic mononuclear compound [Co(bpp-COOMe)2 ](ClO4 )2 (1) (bpp-COOMe=methyl 2,6-di(pyrazol-1-yl)pyridine-4-carboxylate) crystallizes in the monoclinic C2/c space group, and the cobalt(II) ion possesses a pseudo-octahedral environment given by the two mer-coordinated tridentate ligands. Direct-current magnetic data, single-crystal torque magnetometry, and EPR measurements disclosed the easy-axis nature of this cobalt(II) complex, which shows single-molecule magnet behavior when a static field is applied in alternating-current susceptibility measurements. Diamagnetic dilution in the zinc(II) analogue [Zn(bpp-COOMe)2 ](ClO4 )2 (2) afforded the derivative [Zn0.95 Co0.05 (bpp-COOMe)2 ](ClO4 )2 (3), which exhibits slow relaxation of magnetization even in zero field thanks to the reduction of dipolar interactions. Theoretical calculations confirmed the overall electronic structure and the magnetic scenario of the compound as drawn by experimental data, thus confirming the spin-phonon Raman relaxation mechanism, and a direct quantum tunneling in the ground state as the most plausible relaxation pathway in zero field.
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Affiliation(s)
- Luca Rigamonti
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, and INSTM RU of Modena and Reggio Emilia, via G. Campi 103, 41125, Modena, Italy
| | - Nathalie Bridonneau
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, and INSTM RU of Modena and Reggio Emilia, via G. Campi 103, 41125, Modena, Italy.,Current address: Laboratoire Interfaces Traitements Organisation, et Dynamique des Systèmes (ITODYS), UMR 7086 CNRS, Université Paris 7 Diderot, Paris Bât. Lavoisier, 15 rue Jean-Antoine de Baïf, 75205, Paris Cedex 13, France
| | - Giordano Poneti
- Laboratory of Molecular Magnetism (LAMM), Dipartimento di Chimica 'Ugo Schiff', Università degli Studi di Firenze, and INSTM RU of Firenze, via della Lastruccia 3-13, 50019, Sesto Fiorentino, FI, Italy.,Current address: Instituto de Química, Universidade Federal do Rio de Janeiro, 21941-909, Rio de Janeiro, Brazil
| | - Lorenzo Tesi
- Laboratory of Molecular Magnetism (LAMM), Dipartimento di Chimica 'Ugo Schiff', Università degli Studi di Firenze, and INSTM RU of Firenze, via della Lastruccia 3-13, 50019, Sesto Fiorentino, FI, Italy
| | - Lorenzo Sorace
- Laboratory of Molecular Magnetism (LAMM), Dipartimento di Chimica 'Ugo Schiff', Università degli Studi di Firenze, and INSTM RU of Firenze, via della Lastruccia 3-13, 50019, Sesto Fiorentino, FI, Italy
| | - Dawid Pinkowicz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Jesus Jover
- Departament de Química Inorgànica i Orgànica, Institut de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028, Barcelona, Spain
| | - Eliseo Ruiz
- Departament de Química Inorgànica i Orgànica, Institut de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028, Barcelona, Spain
| | - Roberta Sessoli
- Laboratory of Molecular Magnetism (LAMM), Dipartimento di Chimica 'Ugo Schiff', Università degli Studi di Firenze, and INSTM RU of Firenze, via della Lastruccia 3-13, 50019, Sesto Fiorentino, FI, Italy
| | - Andrea Cornia
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, and INSTM RU of Modena and Reggio Emilia, via G. Campi 103, 41125, Modena, Italy
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Sarkar A, Velmurugan G, Rajeshkumar T, Rajaraman G. Deciphering the origin of invariance in magnetic anisotropy in {FeIIS4} complexes: a theoretical perspective. Dalton Trans 2018; 47:9980-9984. [DOI: 10.1039/c8dt02145g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
By employing the state-of-the-art ab initio calculations, we have probed the origin of invariance in ZFS parameters in {FeIIS4} complexes.
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Affiliation(s)
- Arup Sarkar
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai
- India
| | | | | | - Gopalan Rajaraman
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai
- India
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