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Molla M, Saha A, Barman SK, Mandal S. Monomeric Fe(III)-Hydroxo and Fe(III)-Aqua Complexes Display Oxidative Asynchronous Hydrogen Atom Abstraction Reactivity. Chemistry 2024; 30:e202401163. [PMID: 38953593 DOI: 10.1002/chem.202401163] [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: 03/22/2024] [Revised: 06/16/2024] [Accepted: 07/02/2024] [Indexed: 07/04/2024]
Abstract
This paper presents the synthesis and characterization of a series of novel monomeric aqua-ligated iron(III) complexes, [FeIII(L5R)(OH2)]2+ (R=OMe, H, Cl, NO2), supported by an amide-containing pentadentate N5 donor ligand, L5R [HL5R=2-(((1-methyl-1H-imidazol-2-yl)methyl)(pyridin-2-yl-methyl)amino)-N-(5-R-quinolin-8-yl)acetamide]. The complexes were characterized by various spectroscopic and analytical techniques, including electrochemistry and magnetic measurements. The Fe(III)-hydroxo complexes, [FeIII(L5R)(OH)]1+, were generated in situ by deprotonating the corresponding aqua complexes in a pH ~7 aqueous medium. In another way, adding one equivalent of a base to a methanolic solution of the Fe(III)-aqua complexes also produced the Fe(III)-hydroxo complexes. The study uses linoleic fatty acid as a substrate to explore the hydrogen atom abstraction (HAA) reactivity of both hydroxo and aqua complexes. The investigation highlights the substitution effect of the L5R ligand on reactivity, revealing a higher rate when an electron-withdrawing group is present. Hammett analyses and(or) determination of the asynchronicity factor (η) suggest an oxidative asynchronous concerted proton-electron transfer (CPET) pathway for the HAA reactions. Aqua complexes exhibited a higher asynchronicity in CPET, resulting in higher reaction rates than their hydroxo analogs. Overall, the work provides insights into the beneficial role of a higher imbalance in electron-transfer-proton-transfer (ET-PT) contributions in HAA reactivity.
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Affiliation(s)
- Mofijul Molla
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721302, India
| | - Anannya Saha
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Manauli, 140306, India
| | - Suman K Barman
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Manauli, 140306, India
| | - Sukanta Mandal
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721302, India
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2
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Sundaresan S, Becker JG, Eppelsheimer J, Sedykh AE, Carrella LM, Müller-Buschbaum K, Rentschler E. Synergetic spin singlet-quintet switching and luminescence in mononuclear Fe(II) 1,3,4-oxadiazole tetradentate chelates with NCBH 3 co-ligand. Dalton Trans 2023; 52:13181-13189. [PMID: 37664901 DOI: 10.1039/d3dt02420b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
We report the multi-step synthesis of the tetradentate 2-(naphthalen-2-yl)-5-[N,N-bis(2-pyridylmethyl)aminomethyl]-1,3,4-oxadiazole ligand (LTetra-ODA) along with its corresponding [FeII(LTetra-ODA)(NCBH3)2]·1.5CH3OH (C1) complex, which is the first mononuclear 1,3,4-oxadiazole based Fe(II) spin crossover (SCO) complex, and its zinc analogue [ZnII(LTetra-ODA)(NCBH3)2]·0.5H2O (C2). The spin transition is followed by variable temperature (VT-) X-ray crystallography of [Fe(LTetra-ODA)(NCBH3)2]·1.5CH3OH (C1) at 120 and 220 K. The magnetic susceptibility measurements on the bulk sample recorded from 2 to 300 K show that the complex exhibits a complete abrupt reversible spin transition with a T1/2 of 207 K. The loss of the lattice solvent methanol shifts the T1/2 slightly to around 210 K. The spin transition in solution for [Fe(LTetra-ODA)(NCBH3)2]·1.5CH3OH (C1) was followed using the VT-1H-NMR Evans method in CD3CN, with a T1/2 of 357 K. Solid state VT luminescence studies provide some preliminary evidence of interplay of luminescence and spin transition in the [Fe(LTetra-ODA)(NCBH3)2]·1.5CH3OH (C1) complex.
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Affiliation(s)
- Sriram Sundaresan
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Jens-Georg Becker
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Julian Eppelsheimer
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Alexander E Sedykh
- Institute of Inorganic and Analytical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
| | - Luca M Carrella
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
| | - Klaus Müller-Buschbaum
- Institute of Inorganic and Analytical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
| | - Eva Rentschler
- Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
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3
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Kelly CT, Griffin M, Esien K, Felton S, Müller-Bunz H, Morgan GG. Crystallographic Detection of the Spin State in Fe III Complexes. CRYSTAL GROWTH & DESIGN 2022; 22:6429-6439. [PMID: 36345384 PMCID: PMC9634697 DOI: 10.1021/acs.cgd.2c00468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 08/22/2022] [Indexed: 06/16/2023]
Abstract
We report a single example of thermal spin crossover in a series of FeIII complexes, [FeIII(R-sal2323)]+, which typically stabilize the low-spin (S = 1/2) state. Single-crystal X-ray diffraction analysis of 53 such complexes with varying "R" groups, charge-balancing anions, and/or lattice solvation confirms bond lengths in line with an S = 1/2 ground state, with only the [FeIII(4-OMe-sal2323)]NO3 complex (1a) exhibiting longer bond lengths associated with a percentage of the spin sextet form at room temperature. Structural distortion parameters are investigated for the series. A magnetic susceptibility measurement of 1a reveals a gradual, incomplete transition, with T 1/2 = 265 K in the solid state, while Evans method NMR reveals that the sample persists in the low-spin form in solution at room temperature. Computational analysis of the spin state preferences for the cations [FeIII(4-OMe-sal2323)]+ and [FeIII(sal2323)]+ confirmed the energetic preference for the spin doublet form in both, and the thermal spin crossover in complex 1a is therefore attributed to perturbation of the crystal packing on warming.
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Affiliation(s)
- Conor T. Kelly
- School
of Chemistry, University College Dublin, Belfield, Dublin 4D04 N2E5, Ireland
| | - Michael Griffin
- School
of Chemistry, University College Dublin, Belfield, Dublin 4D04 N2E5, Ireland
| | - Kane Esien
- School
of Mathematics and Physics, Queen’s
University Belfast, BelfastBT7 1NN, United Kingdom
| | - Solveig Felton
- School
of Mathematics and Physics, Queen’s
University Belfast, BelfastBT7 1NN, United Kingdom
| | - Helge Müller-Bunz
- School
of Chemistry, University College Dublin, Belfield, Dublin 4D04 N2E5, Ireland
| | - Grace G. Morgan
- School
of Chemistry, University College Dublin, Belfield, Dublin 4D04 N2E5, Ireland
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4
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Crystallographic Evidence of η1-Coordination of Bulky Aminopyridine in Halide-Containing Iron (II) Complexes. CRYSTALS 2022. [DOI: 10.3390/cryst12050697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Reaction of N-(2,6-diisopropylphenyl)-[6-(2,4,6-triisopropylphenyl)-pyridine-2-yl]-amine (ApH) in equimolar ratio with anhydrous FeBr2 and FeI2 in tetrahydrofuran (THF) afforded, after workup in toluene, the first examples of mono(aminopyridine) Fe(II) complexes, [ApHFeBr(µ-Br)]2 (1) and [ApHFeI2(thf)] (2), respectively. X-ray analysis shows 1 to be dimeric, whereas compound 2 is monomeric. In both cases, aminopyridine ligands show rare η1-coordination to Fe through pyridine nitrogen atom. Compound 1 exhibits intramolecular N–H⋯Br hydrogen bonds [3.363 Å] with an N–H⋯Br angle of 158.84°. Hirshfeld surface and fingerprint plots identify the significant intermolecular interactions in the crystal network. Both compounds crystallized in the monoclinic space group. For compound 1, C2/c, the cell parameters are: a = 25.5750(5) Å, b = 10.5150(5) Å, c = 18.9610(8) Å, β = 97.892(5)°, V = 5050.7(3) A3, Z = 4. For compound 2, P21/c, the cell parameters are: a = 10.3180(7) Å, b = 16.1080(10) Å, c = 18.6580(11) Å, β = 102.038(5)°, V = 3032.8(3) A3, Z = 4.
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Three Novel Thiazole-Arm Containing 1,3,4-Oxadiazole-Based [HS-HS] Fe(II) Dinuclear Complexes. CRYSTALS 2022. [DOI: 10.3390/cryst12030404] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Novel synthesis of 2,5-bis[(1,3-thiazol-2-ylmethyl)amino]methyl-1,3,4-oxadiazole (LThiazole) is reported, along with the preparation of three new dinuclear Fe(II) complexes with different counterions [FeII2(μ2-LThiazole)2](BF4)4·2CH3CN (1), [FeII2(μ2-LThiazole)2](ClO4)4 (2) and [FeII2(μ2-LThiazole)2](CF3SO3)4·2CH3CN (3). The obtained complexes were characterized by single-crystal X-ray crystallography, SQUID magnetometry and IR spectroscopy. The structure of the crystalline material was determined at 120 K for 1 and 3. The magnetic properties of all three complexes (1–3) were measured between 2–300 K and clearly show that all three complexes stay in the high-spin state over the measured temperature range.
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Sundaresan S, Kühne IA, Evesson C, Harris MM, Fitzpatrick AJ, Ahmed A, Müller-Bunz H, Morgan GG. Compressed Jahn-Teller octahedra and spin quintet-triplet switching in coordinatively elastic manganese(III) complexes. Polyhedron 2021. [DOI: 10.1016/j.poly.2021.115386] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ouyang ZJ, Mo XY, Ye JQ, Yu XX, Huang SY, Liu XL, Chen WB, Gao S, Dong W. High temperature anionic Fe(III) spin crossover behavior in a mixed-valence Fe(II)/Fe(III) complex. Dalton Trans 2021; 50:5960-5967. [PMID: 33949504 DOI: 10.1039/d1dt00111f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two ion-pair Fe(iii) complexes (PPh4)[FeIII(HATD)2]·2H2O (1, H3ATD = azotetrazolyl-2,7-dihydroxynaphthalene) and [FeII(phen)3][FeIII(HATD)2]2·3DMA·3.5H2O (2, phen = 1,10-phenanthroline, DMA = N,N-dimethylformamide) were synthesized by employing the tridentate ligand H3ATD. Crystal structure analyses reveal that complexes 1 and 2 consist of FeIII ions in an octahedral environment where a FeIII ion is coordinated by two HATD2- ligands forming the [FeIII(HATD)2]- core. The shortest cationanion distance between the phosphorus ion of the (PPh4)+ cation and the ferric ion of the [FeIII(HATD)2]- anion is 13.190 Å in complex 1, whereas that between the ferrous ion of the [FeII(Phen)3]2+ cation and the ferric ion of the [FeIII(HATD)2]- anion is 7.821 Å in complex 2. C-HC and C-HO hydrogen interactions between the [FeII(phen)3]2+ cation and the [FeIII(HATD)2]- anion are observed in 2. Face-to-face π-π stacking interactions between naphthalene rings with the separated interplanar center to center distances of 3.421-3.680 Å were observed, which result in a one-dimensional supramolecular chain in complexes 1 and 2. Magnetic measurements show that complex 1 is in the low-spin (LS) state below 500 K, whereas 2 undergoes a high temperature spin crossover (SCO) between 360 and 500 K. Magneto-structural relationship studies reveal that π-stacking, hydrogen interactions and Coulomb interactions between the [FeIII(HATD)2]- anion and the [FeII(phen)3]2+ cation play a crucial role in the high temperature Fe(iii) SCO behaviour of complex 2.
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Affiliation(s)
- Zhi-Jian Ouyang
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
| | - Xiao-Ying Mo
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
| | - Jia-Qi Ye
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
| | - Xiao-Xuan Yu
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
| | - Shu-Yuan Huang
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
| | - Xiao-Ling Liu
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
| | - Wen-Bin Chen
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
| | - Song Gao
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, P. R. China
| | - Wen Dong
- Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.
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8
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Cruz C, Vega Carvallo AI, Spodine E, Escuer A, Marco JF, Menéndez N, Venegas-Yazigi D, Paredes-García V. New Highly Charged Iron(III) Metal-Organic Cube Stabilized by a Bulky Amine. ACS OMEGA 2020; 5:22238-22247. [PMID: 32923781 PMCID: PMC7482229 DOI: 10.1021/acsomega.0c02420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
In this work, we report a new octanuclear cluster based on FeIII and the ligand 1H-imidazole-4,5-dicarboxylic acid, [Et3NH]12[Fe8(IDC)12]·10DMF·13H2O (1), with a metal core containing eight FeIII connected by only one type of organic ligand. A peak at 573 m/z in the mass spectra of the compound suggests the adduct species {[Fe8(IDC)12]+8H}4-. By X-ray photoelectron spectroscopy, the oxidation state of the iron cation was confirmed to be 3+, also identifying the presence of a quaternary nitrogen species, which act as a countercation of the anionic metal core [Fe8(IDC)12]12-. Mössbauer spectra recorded at different temperatures show an isomer shift and quadrupole splitting parameters that confirm the existence of only FeIII-HS in the structure of 1. X-ray analysis reveals that compound 1 crystallizes in the orthorhombic system space group Ibam, confirming a molecular cluster structure with an almost regular cube as geometry, with the FeIII atoms located at the corners of the cube and connected by μ-1κ2 N,O:2κ2 N',O‴-IDC3- bridges. Additionally, the magnetic measurements reveal a weak antiferromagnetic coupling in the Fe8 III coordination cluster (J = -3.8 cm-1). To the best of our knowledge, 1 is the first member of the family of cubes assembled with 1H-imidazole-4,5-dicarboxylic acid and FeIII cation, exhibiting high pH stability over a broad pH range, making it an ideal candidate for the design of supramolecular structures and metal-organic frameworks.
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Affiliation(s)
- Carlos Cruz
- Facultad
de Ciencias Exactas, Departamento de Ciencias Químicas, Universidad Andres Bello, 8370146 Santiago, Chile
- CEDENNA, 8380494 Santiago, Chile
| | - Andrés Igor Vega Carvallo
- Facultad
de Ciencias Exactas, Departamento de Ciencias Químicas, Universidad Andres Bello, 8370146 Santiago, Chile
- CEDENNA, 8380494 Santiago, Chile
| | - Evgenia Spodine
- CEDENNA, 8380494 Santiago, Chile
- Facultad
de Ciencias Químicas y Farmacéuticas, Departamento de
Química Inorgánica y Analítica, Universidad de Chile, 8380492 Santiago, Chile
| | - Albert Escuer
- Departament
de Química Inorgànica, Universitat
de Barcelona, 08028 Barcelona, Spain
| | - José F. Marco
- Instituto
de Química Física Rocasolano, CSIC, 28013 Madrid, Spain
| | - Nieves Menéndez
- Departamento
de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Diego Venegas-Yazigi
- CEDENNA, 8380494 Santiago, Chile
- Facultad
de Química y Biología, Departamento de Química
de los Materiales, Universidad de Santiago
de Chile, 9170022 Santiago, Chile
| | - Verónica Paredes-García
- Facultad
de Ciencias Exactas, Departamento de Ciencias Químicas, Universidad Andres Bello, 8370146 Santiago, Chile
- CEDENNA, 8380494 Santiago, Chile
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9
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Spin Crossover in Bipyridine Derivative Bridged One-Dimensional Iron(III) Coordination Polymer. MAGNETOCHEMISTRY 2020. [DOI: 10.3390/magnetochemistry6030029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Herein, the syntheses, solid-state molecular structures, and characterization of two types of one-dimensional FeIII coordination polymers showing thermally induced spin crossover are reported. The reaction of [Fe(acen)Cl] (acen2− = N,N′-ethylenebis(acetylacetonylideneaminate) with 3,3′-bpy or 4,4′-bpy (bpy = bipyridine) produced zigzag and linear one-dimensional chain complexes, [Fe(acen)(3,3′-bpy)][BPh4] (1) or [NEt3H][Fe(acen)(4,4′-bpy)][BPh4]2·0.5(4,4′-bpy) (2), respectively, as confirmed by single crystal X-ray diffraction analysis. Variable-temperature single crystal X-ray diffraction measurements, continuous-wave X-band electron paramagnetic resonance (EPR) spectra, 57Fe Mössßauer spectra, and DC magnetic susceptibility data revealed that complex 1 exhibited a gradual and complete spin crossover at a transition temperature of 212 K, while complex 2 undergoes an incomplete spin crossover even at 400 K.
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Barker A, Kelly CT, Kühne IA, Hill S, Krzystek J, Wix P, Esien K, Felton S, Müller-Bunz H, Morgan GG. Spin state solvomorphism in a series of rare S = 1 manganese(iii) complexes. Dalton Trans 2019; 48:15560-15566. [PMID: 31342029 DOI: 10.1039/c9dt02476j] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Structural, magnetic and spectroscopic data of four complex salts, [Mn(napsal2323)]NTf2, 1,[Mn(napsal2323)]ClO4, 2, [Mn(napsal2323)]BF4, 3 and [Mn(napsal2323)]NO3, 4, of the [Mn(napsal2323)]+ complex cation indicate that the Mn3+ ion is stabilized in the rare S = 1 spin triplet form in this ligand sphere. Zero-field splitting values of D = +19.6 cm-1 and |E| = 2.02 cm-1 for complex 1 were obtained by High Field Electron Paramagnetic Resonance (HFEPR) measurements conducted over a range of frequencies. Structural and magnetic data also indicate that co-crystallization of complexes 2 and 3 with 0.5 equivalents of ethanol yields the high spin S = 2 forms of the perchlorate and tetrafluoroborate solvates [Mn(napsal2323)]ClO4·0.5(C2H5OH), 2·0.5EtOH and [Mn(napsal2323)]BF4·0.5(C2H5OH), 3·0.5EtOH.
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Affiliation(s)
- Andrew Barker
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland.
| | - Conor T Kelly
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland.
| | - Irina A Kühne
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland.
| | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA and Department of Physics, Florida State University, Tallahassee, FL 32306, USA
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Paul Wix
- School of Chemistry & CRANN Institute, Trinity College Dublin, University of Dublin, College Green, Dublin 2, Ireland
| | - Kane Esien
- Centre for Nanostructured Media (CNM), School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN, UK
| | - Solveig Felton
- Centre for Nanostructured Media (CNM), School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN, UK
| | - Helge Müller-Bunz
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland.
| | - Grace G Morgan
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland.
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Kühne IA, Ungur L, Esien K, Carter AB, Gordon JD, Pauly C, Müller-Bunz H, Felton S, Zerulla D, Morgan GG. Comparison of two field-induced Er III single ion magnets. Dalton Trans 2019; 48:15679-15686. [PMID: 31512699 DOI: 10.1039/c9dt02434d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present the synthesis, magnetic and photophysical properties of four mononuclear LnIII complexes in two isostructural lattices containing GdIII and ErIII. A heptadentate Schiff base ligand and acetate versus trifluoroacetate were used to synthesise complexes 1-4, among which the two ErIII complexes 2 and 4 exhibit field-induced SIM behaviour with almost similar Ueff values (31.6 K for 2 and 32.7 K for 4). Ab initio calculations show the structure of the low-lying energy states and highlight that there is already significant tunnelling in the ground doublet state, but the application of a weak magnetic field of 0.05 T is sufficient for ac magnetic measurements to suppress tunnelling in the ground state. The calculated main magnetic axes (gZ) of the ground Kramers doublets show small differences between the two ErIII compounds 2 and 4 due to their different ligand fields.
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Affiliation(s)
- Irina A Kühne
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland. and School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
| | - Liviu Ungur
- Department of Chemistry, National University of Singapore, Block S8 Level 3, 3 Science Drive 3, Singapore 117543
| | - Kane Esien
- Centre for Nanostructured Media, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, UK
| | - Anthony B Carter
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131 Karlsruhe, Germany and School of Chemistry, University of Southampton, University Road, Southampton SO17 1BJ, UK
| | - John D Gordon
- School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
| | - Cameron Pauly
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Helge Müller-Bunz
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Solveig Felton
- Centre for Nanostructured Media, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, UK
| | - Dominic Zerulla
- School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
| | - Grace G Morgan
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
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12
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Abstract
The spin crossover (SCO) between multi-stable states in transition metal material is one of the attractive molecular switching phenomena which is responsive to various external stimuli such as temperature, pressure, light, electromagnetic field, radiation, nuclear decay, soft-X-ray, guest molecule inclusion, chemical environments and so forth [...]
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13
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Dankhoff K, Weber B. Isostructural iron(iii) spin crossover complexes with a tridentate Schiff base-like ligand: X-ray structures and magnetic properties. Dalton Trans 2019; 48:15376-15380. [DOI: 10.1039/c9dt00846b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two isostructural iron(iii) spin crossover complexes show anion-size dependent spin crossover.
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Affiliation(s)
- Katja Dankhoff
- Department of Chemistry
- University of Bayreuth
- 95447 Bayreuth
- Germany
| | - Birgit Weber
- Department of Chemistry
- University of Bayreuth
- 95447 Bayreuth
- Germany
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