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Franquesa-Viñas P, Ribas-Ariño J, Santiago R, Deumal M. Enhancing Intramolecular Ferromagnetic Coupling in Tetrathiafulvalene-Nitronyl Nitroxide-Based Compounds through Spin Polarization Mechanism. Chemistry 2024; 30:e202400166. [PMID: 38530333 DOI: 10.1002/chem.202400166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 03/01/2024] [Accepted: 03/11/2024] [Indexed: 03/27/2024]
Abstract
Spin-polarized donor radicals based on tetrathiafulvalene (TTF) derivatives and nitronyl nitroxide (NN) radicals in which one-electron oxidation involves the HOMO instead of the SOMO are well known for exhibiting magnetoresistance. In particular, BTBN consists of one dibromo-TTF and one NN radical, which are linked by a phenyl coupler group. One of the key factors driving magnetoresistance is the presence of intramolecular ferromagnetic (FM) coupling between the oxidized π-donor (TTF+⋅, D unit) and NN (R unit). Here, a theoretical study is carried out to assess suitable candidates with enhanced FM coupling with respect BTBN, which is thus used as a reference. The study is conducted via in silico chemical modification of the substituents of the BTBN basic functional units (D and R radicals, C coupler) to benefit from the spin polarization mechanism to boost the intramolecular FM coupling, aiming to distort the BTBN radical arrangement within the molecular crystal as little as possible, in the event the material can be synthesized. NICSiso(1) and Wiberg's Bond Order are analyzed to further assist in identifying promising potential candidates, since the decrease in aromaticity is expected to enhance the diradical character and give rise to a larger magnetic coupling value. The most favorable diradical building block to replace the BTBN moiety results from using a hydroxyl-ethylene (-(H)C=C(OH)-) as a coupler preserving BTBN original radicals, namely, NN and TTF+⋅ units. This study aims at illustrating the feasibility of improving the intramolecular FM interaction between radical moieties, which is fully realized, as a first step towards the synthesis of new materials with (possibly) enhanced magnetoresistance properties.
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Affiliation(s)
- Pau Franquesa-Viñas
- Departament de Ciència de Materials i Química Física & IQTCUB, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1, E-08028, Barcelona
| | - Jordi Ribas-Ariño
- Departament de Ciència de Materials i Química Física & IQTCUB, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1, E-08028, Barcelona
| | - Raul Santiago
- Departament de Ciència de Materials i Química Física & IQTCUB, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1, E-08028, Barcelona
| | - Mercè Deumal
- Departament de Ciència de Materials i Química Física & IQTCUB, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1, E-08028, Barcelona
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2
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Singha DK, Islam SS, Das C, Ahmed KC N, Nath RC, Mahata P. Synthesis and Investigation of Magnetic Properties of Rod Shaped Micron Sized Ni
4
and Co
2
Ni
2
Cluster based MOFs. Z Anorg Allg Chem 2021. [DOI: 10.1002/zaac.202100225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Shams Sohel Islam
- School of Physics Indian Institute of Science Education and Research Thiruvananthapuram 695551 India
| | - Chhatan Das
- Department of Chemistry Jadavpur University Kolkata 700032 India
| | - Niyaz Ahmed KC
- School of Physics Indian Institute of Science Education and Research Thiruvananthapuram 695551 India
| | - Ramesh Chandra Nath
- School of Physics Indian Institute of Science Education and Research Thiruvananthapuram 695551 India
| | - Partha Mahata
- Department of Chemistry Jadavpur University Kolkata 700032 India
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3
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Kenny EP, Jacko AC, Powell BJ. Tight-Binding Approach to Pyrazine-Mediated Superexchange in Copper-Pyrazine Antiferromagnets. Inorg Chem 2021; 60:11907-11914. [PMID: 34310131 DOI: 10.1021/acs.inorgchem.1c00532] [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
We investigate the cause of spatial superexchange anisotropy in a family of copper-based, quasi-two-dimensional materials with very similar geometries. The compounds in this family differ mainly in their inter-layer separation but they have very different magnetic interactions, even within the basal plane. We use density functional theory and Wannier functions to parameterize two complimentary tight-binding models and show that the superexchange between the Cu2+ ions is dominated by a σ-mediated interaction between hybrid Cu-pyrazine orbitals centered on the copper atoms. We find no correlations between the strength of this exchange interaction and homologous geometric features across the compounds, such as Cu and pyrazine bond lengths and orientations of nearby counterions. We find that the pyrazine tilt angles do not affect the Cu-pyrazine-Cu exchange because the lowest unoccupied molecular orbital on pyrazine is at a very high energy (relative to the frontier orbitals, which are Cu-based). We conclude that careful control of the entire crystal structure, including non-homologous geometric features such as the inter-layer organic ligands, is vital for engineering magnetic properties.
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Affiliation(s)
- E P Kenny
- School of Mathematics and Physics, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - A C Jacko
- School of Mathematics and Physics, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - B J Powell
- School of Mathematics and Physics, The University of Queensland, St Lucia, Queensland 4072, Australia
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4
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Jornet-Somoza J, Cosi F, Fumanal M, Deumal M. Disentangling the magnetic dimensionality of an alleged magnetically isolated cuprate spin-ladder CuHpCl system: a long-lasting issue. Dalton Trans 2021; 50:1754-1765. [PMID: 33459323 DOI: 10.1039/d0dt03499a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Cu2(1,4-diazacycloheptane)2Cl4 (CuHpCl) crystal is a molecular transition metal antiferromagnetic complex, whose magnetism has been a long-lasting issue. The outcome of a variety of experimental studies (on magnetic susceptibility, heat capacity, magnetization, spin gap and INS) reported many different J values depending on the fitting ladder model used. From all available experimental data, one can infer that CuHpCl is a very complex system with many competing microscopic magnetic JAB interactions that lead to its overall antiferromagnetic behavior. A first-principles bottom-up study of CuHpCl is thus necessary in order to fully disentangle its magnetism. Here we incorporate data from ab initio computations providing the magnitude of the JAB interactions to investigate the microscopic magnetic couplings in CuHpCl and, ultimately, to understand the macroscopic magnetic behavior of this crystal. Strikingly, the resulting magnetic topology can be pictured as a 3D network of interacting squared plaquette magnetic building blocks, which does not agree with the suggested ladder motif (with uniform rails) that arises from direct observation of the crystal packing. The computed magnetic susceptibility, heat capacity and magnetization data show good agreement with the experimental data. In spite of this agreement, only the calculated magnetization data are used to discriminate between the different spin regimes in CuHpCl, namely gapped singlet, partially polarized and fully polarized phases. Additional analysis of the magnetic wavefunction enables the conclusion that long-range spin correlation can be discarded as being responsible for the partially polarized phase, whose magnetic response is in fact due to the complex interplay of the magnetic moments in the 3D magnetic topology.
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Affiliation(s)
- J Jornet-Somoza
- Secció Química Física, Dept. Ciència de Materials i Química Física & IQTCUB, Universitat de Barcelona, Martí i Franquès 1, E-08820, Barcelona, Spain. and Nano-Bio Spectroscopy Group and ETSF, Universidad del País Vasco, CFM CSIC-UPV/EHU, E-20018, San Sebastián, Spain
| | - F Cosi
- Secció Química Física, Dept. Ciència de Materials i Química Física & IQTCUB, Universitat de Barcelona, Martí i Franquès 1, E-08820, Barcelona, Spain.
| | - M Fumanal
- Secció Química Física, Dept. Ciència de Materials i Química Física & IQTCUB, Universitat de Barcelona, Martí i Franquès 1, E-08820, Barcelona, Spain.
| | - M Deumal
- Secció Química Física, Dept. Ciència de Materials i Química Física & IQTCUB, Universitat de Barcelona, Martí i Franquès 1, E-08820, Barcelona, Spain.
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5
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Monroe JC, Carvajal MA, Deumal M, Landee CP, Rademeyer M, Turnbull MM. Revisiting the Role of Hydrogen Bonding in the Strong Dimer Superexchange of a 2D Copper(II) Halide Honeycomb-Like Lattice: Structural and Magnetic Study. Inorg Chem 2020; 59:6319-6331. [PMID: 32279485 DOI: 10.1021/acs.inorgchem.0c00433] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The title compound H2L(CuCl3H2O)Cl (H2L = 1-(4'-pyridinium)pyridin-4-ol-ium), 1) was synthesized and investigated structurally and magnetically as well as via a first-principles, bottom-up theoretical analysis of the potential magnetic superexchange pathways. Compound 1 can be described structurally as a well-isolated, distorted 2D-honeycomb lattice with two potential exchange pathways: a dimeric interaction via hydrogen-bonded pairs of (CuCl3H2O) ions and a chain structure via bridging chloride ions. Surprisingly, the experimental magnetic data are best fitted using both a simple dimer model with a Curie-Weiss correction for interdimer exchange (Jdimer = -107.4(1) K, θ = -1.22(4) K) and a strong-rung ladder model (Jrung = -105.8(7) K, Jrail = 2(7) K). Theoretical analysis at the UB3LYP/6-31+G(d) level supports the strong exchange observed through the [CuCl4(H2O)]2- dimer moiety superexchange pathway (-102 K = -71 cm-1). However, the apparent vanishingly small exchange through the single halide bridge is merely a brute average of competing ferromagnetic (FM) (+24.8 K = +17.0 cm-1) and antiferromagnetic (AFM) (-21.0 K = -14.6 cm-1) exchange interactions. Our computational study shows that these fitting parameters carry no physical meaning since a honeycomb plaquette must be taken as magnetic building block for 1. The competition between FM and AFM pair interactions leads to geometrical frustration in 1 and could induce interesting magnetic response at low temperatures, if the magnetic exchange is adequately tuned by modifying substituents in ligands and, in turn, interactions within the crystal packing.
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Affiliation(s)
- Jeffrey C Monroe
- Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, Massachusetts 01610, United States
| | - M Angels Carvajal
- Department Ciència de Materials i Química Física & IQCTUB, Universitat de Barcelona, Martí i Franquès 1, Barcelona E-08028, Spain
| | - Mercè Deumal
- Department Ciència de Materials i Química Física & IQCTUB, Universitat de Barcelona, Martí i Franquès 1, Barcelona E-08028, Spain
| | - Christopher P Landee
- Department of Physics, Clark University, 950 Main Street, Worcester, Massachusetts 01610, United States
| | - Melanie Rademeyer
- Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Mark M Turnbull
- Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, Massachusetts 01610, United States
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6
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Monroe JC, Landee CP, Turnbull MM, Polson M, Wikaira JL. Halide-bridged Cu(pyrazine)2 perchlorate layers: Structure and magnetism. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.07.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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7
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Jornet-Somoza J, Deumal M, Borge J, Robb MA. A Definition of the Magnetic Transition Temperature Using Valence Bond Theory. J Phys Chem A 2018; 122:2168-2177. [DOI: 10.1021/acs.jpca.7b10657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Joaquim Jornet-Somoza
- Departament
de Ciència de Materials i Química Física and
IQTCUB, Facultat de Química, Universitat de Barcelona, Martí
i Franquès 1, E-08028 Barcelona, Spain
- Nano-Bio
Spectroscopy Group and ETSF Scientific Development Centre, Department
of Materials Physics, University of the Basque Country, CFM CSIC-UPV/EHU-MPC
and DIPC, Tolosa Hiribidea 72, E-20018 Donostia-San Sebastián, Spain
| | - Mercè Deumal
- Departament
de Ciència de Materials i Química Física and
IQTCUB, Facultat de Química, Universitat de Barcelona, Martí
i Franquès 1, E-08028 Barcelona, Spain
| | - Juan Borge
- Nano-Bio
Spectroscopy Group and ETSF Scientific Development Centre, Department
of Materials Physics, University of the Basque Country, CFM CSIC-UPV/EHU-MPC
and DIPC, Tolosa Hiribidea 72, E-20018 Donostia-San Sebastián, Spain
| | - Michael A. Robb
- Department
of Chemistry, Imperial College London, South Kensington Campus, SW7 2AZ London, United Kingdom
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8
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Postulka L, Winter SM, Mihailov AG, Mailman A, Assoud A, Robertson CM, Wolf B, Lang M, Oakley RT. Spin Frustration in an Organic Radical Ion Salt Based on a Kagome-Coupled Chain Structure. J Am Chem Soc 2016; 138:10738-41. [PMID: 27537064 DOI: 10.1021/jacs.6b05079] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electro-oxidation of the quinoidal bisdithiazole BT in dichloroethane in the presence of [Bu4N][GaBr4] affords the 1:1 radical ion salt [BT][GaBr4], crystals of which belong to the trigonal space group P3. The packing pattern of the radical cations provides a rare example of an organic kagome basket structure, with S = 1/2 radical ion chains located at the triangular corners of a trihexagonal lattice. Magnetic measurements over a wide temperature range from 30 mK to 300 K suggest strongly frustrated AFM interactions on the scale of J/kb ∼ 30 K, but reveal no anomalies that would be associated with magnetic order. These observations are discussed in terms of the symmetry allowed magnetic interactions within and between the frustrated layers.
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Affiliation(s)
- Lars Postulka
- Physikalisches Institut, Goethe-Universität , Frankfurt 60438, Germany
| | - Stephen M Winter
- Physikalisches Institut, Goethe-Universität , Frankfurt 60438, Germany
| | - Adam G Mihailov
- Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Aaron Mailman
- Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Abdeljalil Assoud
- Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Craig M Robertson
- Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom
| | - Bernd Wolf
- Physikalisches Institut, Goethe-Universität , Frankfurt 60438, Germany
| | - Michael Lang
- Physikalisches Institut, Goethe-Universität , Frankfurt 60438, Germany
| | - Richard T Oakley
- Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
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9
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Fumanal M, Deumal M. The quest for rationalizing the magnetism in purely organic semiquinone-bridged bisdithiazolyl molecular magnets. Phys Chem Chem Phys 2016; 18:20738-49. [PMID: 27412491 DOI: 10.1039/c6cp02699k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Semiquinone-bridged bisdithiazolyl-based radicals (XBBO) are appealing purely organic magnetic building blocks for the synthesis of new functional materials. Remarkably, for the phenyl-derivative PhBBO, the rationalization of its magnetism becomes a proof of concept that DFT can dramatically fail to evaluate JAB magnetic interactions between purely organic radical pairs. Instead, wavefunction-based methods are required. Once JAB's are fully characterized, the magnetic topology of PhBBO is disclosed to consist of ferromagnetic FM π-stacks that are very weakly coupled (by FM and AFM JAB interactions). The magnetic susceptibility χT(T) and magnetization M(H) of PhBBO are then calculated using a first-principles bottom-up approach. The study of the unit cell contraction upon cooling from room temperature to zero-Kelvin is relevant to propose a suitable model for the phase transition that occurs at 4.5 K. A simplistic picture tells us that the antiparallel-aligned 1D-FM-chains convert into domains of weakly either FM- or AFM-coupled 1D-FM-chains. Accordingly, the presence of these domains may introduce geometrical spin frustration below 4.5 K.
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Affiliation(s)
- Maria Fumanal
- Departament de Ciència de Materials i Química Física and IQTCUB, Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona, Spain. and Laboratoire de Chimie Quantique, Université de Strasbourg, 4 rue Blaise Pascal, F-67000 Strasbourg, France
| | - Mercè Deumal
- Departament de Ciència de Materials i Química Física and IQTCUB, Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona, Spain.
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10
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Manson JL, Schlueter JA, Garrett KE, Goddard PA, Lancaster T, Möller JS, Blundell SJ, Steele AJ, Franke I, Pratt FL, Singleton J, Bendix J, Lapidus SH, Uhlarz M, Ayala-Valenzuela O, McDonald RD, Gurak M, Baines C. Bimetallic MOFs (H3O)x[Cu(MF6)(pyrazine)2]·(4 − x)H2O (M = V4+, x = 0; M = Ga3+, x = 1): co-existence of ordered and disordered quantum spins in the V4+ system. Chem Commun (Camb) 2016; 52:12653-12656. [DOI: 10.1039/c6cc05873f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
These bimetallic MOFs contain [Cu(pyz)2]2+ sheets and MF6n− octahedra whereby only the Cu(ii) moments magnetically order.
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11
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Vela S, Fumanal M, Deumal M. The origin of the antiferromagnetic behaviour of the charge-transfer compound (HMTTF)[Ni(mnt)2]. Dalton Trans 2015; 44:608-14. [DOI: 10.1039/c4dt03117b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein we disclose the origin of the magnetic behaviour of the remarkable (HMTTF)[Ni(mnt)2] charge-transfer compound.
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Affiliation(s)
- Sergi Vela
- Departament de Química Física & IQTCUB
- Facultat de Química
- Universitat de Barcelona
- Barcelona
- Spain
| | - Maria Fumanal
- Departament de Química Física & IQTCUB
- Facultat de Química
- Universitat de Barcelona
- Barcelona
- Spain
| | - Mercè Deumal
- Departament de Química Física & IQTCUB
- Facultat de Química
- Universitat de Barcelona
- Barcelona
- Spain
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12
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Vela S, Sopena A, Ribas-Arino J, Novoa JJ, Deumal M. Elucidating the 2D Magnetic Topology of the ‘Metal-Radical’ TTTA⋅Cu(hfac)2System. Chemistry 2014; 20:7083-90. [DOI: 10.1002/chem.201304712] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Indexed: 11/08/2022]
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