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Zheng H, Wang X, Li X, Wang C, Liu J. Spin-crossover in a trinuclear [Fe3(4-C3trz)6(H2O)6] (ClO4)] compound. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.109629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Yamaguchi Y, Takano R, Ishida T. Pincer-type bisnitroxide radicals involving tetramethylenedioxy and o-xylylenedioxy bridges. Tetrahedron Lett 2022. [DOI: 10.1016/j.tetlet.2022.153841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Sutter JP, Béreau V, Jubault V, Bretosh K, Pichon C, Duhayon C. Magnetic anisotropy of transition metal and lanthanide ions in pentagonal bipyramidal geometry. Chem Soc Rev 2022; 51:3280-3313. [PMID: 35353106 DOI: 10.1039/d2cs00028h] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The magnetic anisotropy associated with a pentagonal bipyramidal (PBP) coordination sphere is examined on the basis of experimental and theoretical investigations. The origin and the characteristics of this anisotropy are discussed in relation to the electronic configuration of the metal ions. The effects of crystal field, structural distortion, and a second-coordination sphere on the observed anisotropies for transition meal and lanthanide ions are outlined. For the Ln derivatives, we focus on compounds showing SMM-like behavior (i.e. slow relaxation of their magnetization) in order to highlight the essential chemical and structural parameters for achieving strong axial anisotropy. The use of PBP complexes to impart controlled magnetic anisotropy in polynuclear species such as SMMs or SCMs is also addressed. This review of the magnetic anisotropies associated with a pentagonal bipyramidal coordination sphere for transition metal and lanthanide ions is intended to highlight some general trends that can guide chemists towards designing a compound with specific properties.
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Affiliation(s)
- Jean-Pascal Sutter
- Laboratoire de Chimie de Coordination du CNRS (LCC-CNRS), Université de Toulouse, CNRS, Toulouse, France.
| | - Virginie Béreau
- Laboratoire de Chimie de Coordination du CNRS (LCC-CNRS), Université de Toulouse, CNRS, Toulouse, France. .,Université de Toulouse, Institut Universitaire de Technologie Paul Sabatier-Département de Chimie, Av. Georges Pompidou, F-81104 Castres, France
| | - Valentin Jubault
- Laboratoire de Chimie de Coordination du CNRS (LCC-CNRS), Université de Toulouse, CNRS, Toulouse, France.
| | - Kateryna Bretosh
- Laboratoire de Chimie de Coordination du CNRS (LCC-CNRS), Université de Toulouse, CNRS, Toulouse, France.
| | - Céline Pichon
- Laboratoire de Chimie de Coordination du CNRS (LCC-CNRS), Université de Toulouse, CNRS, Toulouse, France.
| | - Carine Duhayon
- Laboratoire de Chimie de Coordination du CNRS (LCC-CNRS), Université de Toulouse, CNRS, Toulouse, France.
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Tretyakov EV, Ovcharenko VI, Terent'ev AO, Krylov IB, Magdesieva TV, Mazhukin DG, Gritsan NP. Conjugated nitroxide radicals. RUSSIAN CHEMICAL REVIEWS 2022. [DOI: 10.1070/rcr5025] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Molecular S = 2 High-Spin, S = 0 Low-Spin and S = 0 ⇄ 2 Spin-Transition/-Crossover Nickel(II)-Bis(nitroxide) Coordination Compounds. INORGANICS 2021. [DOI: 10.3390/inorganics9020010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Heterospin systems have a great advantage in frontier orbital engineering since they utilize a wide diversity of paramagnetic chromophores and almost infinite combinations and mutual geometries. Strong exchange couplings are expected in 3d–2p heterospin compounds, where the nitroxide (aminoxyl) oxygen atom has a direct coordination bond with a nickel(II) ion. Complex formation of nickel(II) salts and tert-butyl 2-pyridyl nitroxides afforded a discrete 2p–3d–2p triad. Ferromagnetic coupling is favored when the magnetic orbitals, nickel(II) dσ and radical π*, are arranged in a strictly orthogonal fashion, namely, a planar coordination structure is characterized. In contrast, a severe twist around the coordination bond gives an orbital overlap, resulting in antiferromagnetic coupling. Non-chelatable nitroxide ligands are available for highly twisted and practically diamagnetic complexes. Here, the Ni–O–N–Csp2 torsion (dihedral) angle is supposed to be a useful metric to describe the nickel ion dislocated out of the radical π* nodal plane. Spin-transition complexes exhibited a planar coordination structure in a high-temperature phase and a nonplanar structure in a low-temperature phase. The gradual spin transition is described as a spin equilibrium obeying the van’t Hoff law. Density functional theory calculation indicates that the energy level crossing of the high- and low-spin states. The optimized structures of diamagnetic and high-spin states well agreed with the experimental large and small torsions, respectively. The novel mechanism of the present spin transition lies in the ferro-/antiferromagnetic coupling switch. The entropy-driven mechanism is plausible after combining the results of the related copper(II)-nitroxide compounds. Attention must be paid to the coupling parameter J as a variable of temperature in the magnetic analysis of such spin-transition materials. For future work, the exchange coupling may be tuned by chemical modification and external stimulus, because it has been clarified that the parameter is sensitive to the coordination structure and actually varies from 2J/kB = +400 K to −1400 K.
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Hyre AS, Doerrer LH. A structural and spectroscopic overview of molecular lanthanide complexes with fluorinated O-donor ligands. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2019.213098] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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7
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Kyoden Y, Homma Y, Ishida T. High-Spin and Incomplete Spin-Crossover Polymorphs in Doubly Chelated [Ni(L) 2Br 2] (L = tert-Butyl 5-Phenyl-2-pyridyl Nitroxide). Inorg Chem 2019; 58:10743-10755. [PMID: 31368687 DOI: 10.1021/acs.inorgchem.9b00885] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Complexation of nickel(II) bromide with tert-butyl 5-phenyl-2-pyridyl nitroxide (phpyNO) gave two morphs of doubly chelated [Ni(phpyNO)2Br2] as a 2p-3d-2p heterospin triad. The α phase crystallizes in the orthorhombic space group Pbcn. An asymmetric unit involves a half-molecule. The torsion angle around Ni-O-N-C2py is as small as 6.5(3)° at 100 K and 7.0(6)° at 400 K, guaranteeing an orthogonal arrangement between the magnetic radical π* and metal 3dx2-y2 and 3dz2 orbitals. Magnetic study revealed the high-spin ground state with the exchange coupling constant 2J/kB = +288(5) K, on the basis of a symmetrical spin Hamiltonian. The β phase crystallizes in the monoclinic space group P21/n. The whole molecule is an independent unit. The Ni-O-N-C2py torsion angles are 24.2(6) and 37.2(5)° at 100 K and 10.4(7) and 25.9(6)° at 400 K. A magnetic study revealed a very gradual and nonhysteretic spin transition. An analysis based on the van't Hoff equation gave a successful fit with the spin-crossover temperature of 134(1) K, although the susceptibility did not reach the theoretical high-spin value at 400 K. Density functional theory calculation on the β phase showed ground Stotal = 0 in the low-temperature structure while Stotal = 2 in the high-temperature structure, supporting the synchronized exchange coupling switch on both sides. Consequently, the β phase can be recognized as an "incomplete spin crossover" material, as a result of conflicting thermal depopulation effects in a high-temperature region.
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Affiliation(s)
- Yukiya Kyoden
- Department of Engineering Science , The University of Electro-Communications , Chofu, Tokyo 182-8585 , Japan
| | - Yuta Homma
- Department of Engineering Science , The University of Electro-Communications , Chofu, Tokyo 182-8585 , Japan
| | - Takayuki Ishida
- Department of Engineering Science , The University of Electro-Communications , Chofu, Tokyo 182-8585 , Japan
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Kashiro A, Kyoden Y, Okazawa A, Ishida T. Moving Organic Molecules in Crystalline Solids: Gradual Structural Transition and Spin Transition/Crossover. J SYN ORG CHEM JPN 2019. [DOI: 10.5059/yukigoseikyokaishi.77.684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | | | | | - Takayuki Ishida
- Department of Engineering Science, The University of Electro-Communications
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Kaur G, Polson MIJ, Hartshorn RM. 4′-(2-Methylphenyl)-2,2′:6′,2″-terpyridine: coordination chemistry with Ni(II), Cu(II), Zn(II) and Ag(I). J COORD CHEM 2019. [DOI: 10.1080/00958972.2019.1580698] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Gurpreet Kaur
- School of Physical and Chemical Sciences, University of Canterbury, Christchurch, New Zealand
| | - Matthew I. J. Polson
- School of Physical and Chemical Sciences, University of Canterbury, Christchurch, New Zealand
| | - Richard M. Hartshorn
- School of Physical and Chemical Sciences, University of Canterbury, Christchurch, New Zealand
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Yoshitake T, Ishida T. Ferromagnetic Chains of Ground Triplet 5-Methoxy-1,3-phenylene Bis( tert-butyl nitroxide). CHEM LETT 2016. [DOI: 10.1246/cl.151174] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Toru Yoshitake
- Department of Engineering Science, The University of Electro-Communications
| | - Takayuki Ishida
- Department of Engineering Science, The University of Electro-Communications
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Thermally Activated Paramagnets from Diamagnetic Polymers of Biphenyl-3,5-diyl Bis(tert-butyl Nitroxides) Carrying Methyl and Fluoro Groups at the 2’- and 5’-Positions. CRYSTALS 2016. [DOI: 10.3390/cryst6030030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Kawakami H, Tonegawa A, Ishida T. A designed room-temperature triplet ligand from pyridine-2,6-diyl bis(tert-butyl nitroxide). Dalton Trans 2016; 45:1306-9. [PMID: 26615801 DOI: 10.1039/c5dt04218f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The magnetic study on newly developed 4-mesitylpyridine-2,6-diyl bis(tert-butyl nitroxide) shows that almost the whole population has a ground triplet state at room temperature, and the ability of complex formation as a tridentate triplet ligand was proven with a diamagnetic yttrium(iii) ion.
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Affiliation(s)
- Hinako Kawakami
- Department of Engineering Science, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan.
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Gryn'ova G, Coote ML, Corminboeuf C. Theory and practice of uncommon molecular electronic configurations. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2015; 5:440-459. [PMID: 27774112 PMCID: PMC5057308 DOI: 10.1002/wcms.1233] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 09/15/2015] [Accepted: 09/17/2015] [Indexed: 11/10/2022]
Abstract
The electronic configuration of the molecule is the foundation of its structure and reactivity. The spin state is one of the key characteristics arising from the ordering of electrons within the molecule's set of orbitals. Organic molecules that have open-shell ground states and interesting physicochemical properties, particularly those influencing their spin alignment, are of immense interest within the up-and-coming field of molecular electronics. In this advanced review, we scrutinize various qualitative rules of orbital occupation and spin alignment, viz., the aufbau principle, Hund's multiplicity rule, and dynamic spin polarization concept, through the prism of quantum mechanics. While such rules hold in selected simple cases, in general the spin state of a system depends on a combination of electronic factors that include Coulomb and Pauli repulsion, nuclear attraction, kinetic energy, orbital relaxation, and static correlation. A number of fascinating chemical systems with spin states that fluctuate between triplet and open-shell singlet, and are responsive to irradiation, pH, and other external stimuli, are highlighted. In addition, we outline a range of organic molecules with intriguing non-aufbau orbital configurations. In such quasi-closed-shell systems, the singly occupied molecular orbital (SOMO) is energetically lower than one or more doubly occupied orbitals. As a result, the SOMO is not affected by electron attachment to or removal from the molecule, and the products of such redox processes are polyradicals. These peculiar species possess attractive conductive and magnetic properties, and a number of them that have already been developed into molecular electronics applications are highlighted in this review. WIREs Comput Mol Sci 2015, 5:440-459. doi: 10.1002/wcms.1233 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Ganna Gryn'ova
- Institut des Sciences et Ingénierie Chimiques Ecole polytechnique fédérale de Lausanne Lausanne Switzerland
| | - Michelle L Coote
- Australian Research Council Centre of Excellence for Electromaterials Science, Research School of Chemistry Australian National University Canberra Australia
| | - Clemence Corminboeuf
- Institut des Sciences et Ingénierie Chimiques Ecole polytechnique fédérale de Lausanne Lausanne Switzerland
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