1
|
Spielvogel KD, Campbell EJ, Chowdhury SR, Benner F, Demir S, Hatzis GP, Petras HR, Sembukuttiarachchige D, Shepherd JJ, Thomas CM, Vlaisavljevich B, Daly SR. Modulation of Fe-Fe distance and spin in diiron complexes using tetradentate ligands with different flanking donors. Chem Commun (Camb) 2024. [PMID: 39028006 DOI: 10.1039/d4cc02522a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Here we report the synthesis and characterization of diiron complexes containing triaryl N4 and N2S2 ligands derived from o-phenylenediamine. The complexes display significant differences in Fe-Fe distances and magnetic properties that depend on the identity of the flanking NMe2 and SMe donor groups.
Collapse
Affiliation(s)
- Kyle D Spielvogel
- The University of Iowa, Department of Chemistry, E331 Chemistry Building, Iowa City, IA 52242, USA.
| | - Emily J Campbell
- The University of Iowa, Department of Chemistry, E331 Chemistry Building, Iowa City, IA 52242, USA.
| | - Sabyasachi Roy Chowdhury
- The University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA
| | - Florian Benner
- Michigan State University, Department of Chemistry, 578 South Shaw Lane, East Lansing, Michigan 48824, USA
| | - Selvan Demir
- Michigan State University, Department of Chemistry, 578 South Shaw Lane, East Lansing, Michigan 48824, USA
| | - Gillian P Hatzis
- The Ohio State University, Department of Chemistry and Biochemistry, 100 West 18th Ave, Columbus, OH 43210, USA
| | - Hayley R Petras
- The University of Iowa, Department of Chemistry, E331 Chemistry Building, Iowa City, IA 52242, USA.
| | | | - James J Shepherd
- The University of Iowa, Department of Chemistry, E331 Chemistry Building, Iowa City, IA 52242, USA.
| | - Christine M Thomas
- The Ohio State University, Department of Chemistry and Biochemistry, 100 West 18th Ave, Columbus, OH 43210, USA
| | - Bess Vlaisavljevich
- The University of Iowa, Department of Chemistry, E331 Chemistry Building, Iowa City, IA 52242, USA.
- The University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA
| | - Scott R Daly
- The University of Iowa, Department of Chemistry, E331 Chemistry Building, Iowa City, IA 52242, USA.
| |
Collapse
|
2
|
Nagelski AL, Ozerov M, Fataftah MS, Krzystek J, Greer SM, Holland PL, Telser J. Electronic Structure of Three-Coordinate Fe II and Co II β-Diketiminate Complexes. Inorg Chem 2024; 63:4511-4526. [PMID: 38408452 DOI: 10.1021/acs.inorgchem.3c03388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
The β-diketiminate supporting group, [ArNCRCHCRNAr]-, stabilizes low coordination number complexes. Four such complexes, where R = tert-butyl, Ar = 2,6-diisopropylphenyl, are studied: (nacnactBu)ML, where M = FeII, CoII and L = Cl, CH3. These are denoted FeCl, FeCH3, CoCl, and CoCH3 and have been previously reported and structurally characterized. The two FeII complexes (S = 2) have also been previously characterized by Mössbauer spectroscopy, but only indirect assessment of the ligand-field splitting and zero-field splitting (zfs) parameters was available. Here, EPR spectroscopy is used, both conventional field-domain for the CoII complexes (with S = 3/2) and frequency-domain, far-infrared magnetic resonance spectroscopy (FIRMS) for all four complexes. The CoII complexes were also studied by magnetometry. These studies allow accurate determination of the zfs parameters. The two FeII complexes are similar with nearly axial zfs and large magnitude zfs given by D = -37 ± 1 cm-1 for both. The two CoII complexes likewise exhibit large and nearly axial zfs, but surprisingly, CoCl has positive D = +55 cm-1 while CoCH3 has negative D = -49 cm-1. Theoretical methods were used to probe the electronic structures of the four complexes, which explain the experimental spectra and the zfs parameters.
Collapse
Affiliation(s)
- Alexandra L Nagelski
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Majed S Fataftah
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Samuel M Greer
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Patrick L Holland
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605, United States
| |
Collapse
|
3
|
Roy M, Gompa TP, Greer SM, Jiang N, Nassar LS, Steiner A, Bacsa J, Stein BW, La Pierre HS. Intervalence Charge Transfer in Nonbonding, Mixed-Valence, Homobimetallic Ytterbium Complexes. J Am Chem Soc 2024; 146:5560-5568. [PMID: 38373439 PMCID: PMC10910554 DOI: 10.1021/jacs.3c13906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 01/20/2024] [Accepted: 01/30/2024] [Indexed: 02/21/2024]
Abstract
There are several reports of compounds containing lanthanide ions in two different formal oxidation states; however, there are strikingly few examples of intervalence charge transfer (IVCT) transitions observed for these complexes, with those few occurrences limited to extended solids rather than molecular species. Herein, we report the synthesis, characterization, and computational analysis for a series of ytterbium complexes including a mixed-valence Yb25+ complex featuring a remarkably short Yb···Yb distance of 2.9507(8) Å. In contrast to recent reports of short Ln···Ln distances attributed to bonding through 5d orbitals, the formally Yb25+ complex presented here displays clear localization of Ln2+ and Ln3+ character and yet still displays an IVCT in the visible spectrum. These results demonstrate the ability to tune the electronic structure of formally mixed oxidation state lanthanide complexes: the high exchange stabilization of the Yb2+ 4f14 configuration disfavors the formation of a 5d1 bonding configuration, and the short metal-metal distance enforced by the ligand framework allows for the first observed lanthanide IVCT in a molecular system.
Collapse
Affiliation(s)
- Michael
D. Roy
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
| | - Thaige P. Gompa
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
| | - Samuel M. Greer
- Los
Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Ningxin Jiang
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
| | - Lila S. Nassar
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United
States
| | - Alexander Steiner
- Department
of Chemistry, University of Liverpool, Liverpool L69 7Zd, United Kingdom
| | - John Bacsa
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
| | - Benjamin W. Stein
- Los
Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Henry S. La Pierre
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332-0400, United States
- Nuclear
and Radiological Engineering Program, Georgia
Institute of Technology, Atlanta, Georgia 30332-0400, United States
- Physical
Sciences Division, Pacific Northwest National
Laboratory, Richland, Washington 99352, United States
| |
Collapse
|
4
|
Wojnar MK, Kundu K, Kairalapova A, Wang X, Ozarowski A, Berkelbach TC, Hill S, Freedman DE. Ligand field design enables quantum manipulation of spins in Ni 2+ complexes. Chem Sci 2024; 15:1374-1383. [PMID: 38274078 PMCID: PMC10806831 DOI: 10.1039/d3sc04919a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 12/02/2023] [Indexed: 01/27/2024] Open
Abstract
Creating the next generation of quantum systems requires control and tunability, which are key features of molecules. To design these systems, one must consider the ground-state and excited-state manifolds. One class of systems with promise for quantum sensing applications, which require water solubility, are d8 Ni2+ ions in octahedral symmetry. Yet, most Ni2+ complexes feature large zero-field splitting, precluding manipulation by commercial microwave sources due to the relatively large spin-orbit coupling constant of Ni2+ (630 cm-1). Since low lying excited states also influence axial zero-field splitting, D, a combination of strong field ligands and rigidly held octahedral symmetry can ameliorate these challenges. Towards these ends, we performed a theoretical and computational analysis of the electronic and magnetic structure of a molecular qubit, focusing on the impact of ligand field strength on D. Based on those results, we synthesized 1, [Ni(ttcn)2](BF4)2 (ttcn = 1,4,7-trithiacyclononane), which we computationally predict will have a small D (Dcalc = +1.15 cm-1). High-field high-frequency electron paramagnetic resonance (EPR) data yield spin Hamiltonian parameters: gx = 2.1018(15), gx = 2.1079(15), gx = 2.0964(14), D = +0.555(8) cm-1 and E = +0.072(5) cm-1, which confirm the expected weak zero-field splitting. Dilution of 1 in the diamagnetic Zn analogue, [Ni0.01Zn0.99(ttcn)2](BF4)2 (1') led to a slight increase in D to ∼0.9 cm-1. The design criteria in minimizing D in 1via combined computational and experimental methods demonstrates a path forward for EPR and optical addressability of a general class of S = 1 spins.
Collapse
Affiliation(s)
- Michael K Wojnar
- Department of Chemistry, Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA
| | - Krishnendu Kundu
- National High Magnetic Field Laboratory Tallahassee Florida 32310 USA
| | | | - Xiaoling Wang
- National High Magnetic Field Laboratory Tallahassee Florida 32310 USA
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory Tallahassee Florida 32310 USA
| | | | - Stephen Hill
- National High Magnetic Field Laboratory Tallahassee Florida 32310 USA
- Department of Physics, Florida State University Florida 32306 USA
| | - Danna E Freedman
- Department of Chemistry, Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA
| |
Collapse
|
5
|
Scott AG, Galico DA, Bogacz I, Oyala PH, Yano J, Suturina EA, Murugesu M, Agapie T. High-Spin and Reactive Fe 13 Cluster with Exposed Metal Sites. Angew Chem Int Ed Engl 2023; 62:e202313880. [PMID: 37871234 PMCID: PMC10962695 DOI: 10.1002/anie.202313880] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 10/23/2023] [Accepted: 10/23/2023] [Indexed: 10/25/2023]
Abstract
Atomically defined large metal clusters have applications in new reaction development and preparation of materials with tailored properties. Expanding the synthetic toolbox for reactive high nuclearity metal complexes, we report a new class of Fe clusters, Tp*4 W4 Fe13 S12 , displaying a Fe13 core with M-M bonds that has precedent only in main group and late metal chemistry. M13 clusters with closed shell electron configurations can show significant stability and have been classified as superatoms. In contrast, Tp*4 W4 Fe13 S12 displays a large spin ground state of S=13. This compound performs small molecule activations involving the transfer of up to 12 electrons resulting in significant cluster rearrangements.
Collapse
Affiliation(s)
- Anna G. Scott
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 (USA)
| | - Diogo Alves Galico
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1 N6 N5 (Canada)
| | - Isabel Bogacz
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory Berkeley, CA 94720 (USA)
| | - Paul H. Oyala
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 (USA)
| | - Junko Yano
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory Berkeley, CA 94720 (USA)
| | | | - Muralee Murugesu
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1 N6 N5 (Canada)
| | - Theodor Agapie
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 (USA)
| |
Collapse
|
6
|
Hertler PR, Lewis RA, Wu G, Hayton TW. Measuring Metal-Metal Communication in a Series of Ketimide-Bridged [Fe 2] 6+ Complexes. Inorg Chem 2023; 62:11829-11836. [PMID: 37462407 DOI: 10.1021/acs.inorgchem.3c01109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023]
Abstract
Reaction of Fe(acac)3 with 3 equiv of Li[N═C(R)Ph] (R = Ph, tBu) results in the formation of the [Fe2]6+ complexes, [Fe2(μ-N═C(R)Ph)2(N═C(R)Ph)4] (R = Ph, 1; tBu, 2), in low to moderate yields. Reaction of FeCl2 with 6 equiv of Li(N═C13H8) (HN═C13H8 = 9-fluorenone imine) results in the formation of [Li(THF)2]2[Fe(N═C13H8)4] (3) in good yield. Subsequent oxidation of 3 with ca. 0.8 equiv of I2 generates the [Fe2]6+ complex, [Fe2(μ-N═C13H8)2(N═C13H8)4] (4), along with free fluorenyl ketazine. Complexes 1, 2, and 4 were characterized by 1H NMR spectroscopy, X-ray crystallography, 57Fe Mössbauer spectroscopy, and SQUID magnetometry. The Fe-Fe distances in 1, 2, and 4 range from 2.803(7) to 2.925(1) Å, indicating that no direct Fe-Fe interaction is present in these complexes. The 57Fe Mössbauer spectra for complexes 1, 2, and 4 are all consistent with the presence of symmetry-equivalent high-spin Fe3+ centers. Finally, all three complexes exhibit a similar degree of antiferromagnetic coupling between the metal centers (J = -26 to -30 cm-1), as ascertained by SQUID magnetometry.
Collapse
Affiliation(s)
- Phoebe R Hertler
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Richard A Lewis
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| |
Collapse
|
7
|
Spentzos AZ, May SR, Confer AM, Gau MR, Carroll PJ, Goldberg DP, Tomson NC. Investigating Metal-Metal Bond Polarization in a Heteroleptic Tris-Ylide Diiron System. Inorg Chem 2023; 62:11487-11499. [PMID: 37428000 PMCID: PMC11071007 DOI: 10.1021/acs.inorgchem.3c01068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
This article describes the synthesis, characterization, and S-atom transfer reactivity of a series of C3v-symmetric diiron complexes. The iron centers in each complex are coordinated in distinct ligand environments, with one (FeN) bound in a pseudo-trigonal bipyramidal geometry by three phosphinimine nitrogens in the equatorial plane, a tertiary amine, and the second metal center (FeC). FeC is coordinated, in turn, by FeN, three ylidic carbons in a trigonal plane, and, in certain cases, by an axial oxygen donor. The three alkyl donors at FeC form through the reduction of the appended N═PMe3 arms of the monometallic parent complex. The complexes were studied crystallographically, spectroscopically (NMR, UV-vis, and Mössbauer), and computationally (DFT, CASSCF) and found to be high-spin throughout, with short Fe-Fe distances that belie weak orbital overlap between the two metals. Further, the redox nature of this series allowed for the determination that oxidation is localized to the FeC. S-atom transfer chemistry resulted in the formal insertion of a S atom into the Fe-Fe bond of the reduced diiron complex to form a mixture of Fe4S and Fe4S2 products.
Collapse
Affiliation(s)
- Ariana Z. Spentzos
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University
of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104,
USA
| | - Sam R. May
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University
of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104,
USA
| | - Alex M. Confer
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University
of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104,
USA
| | - Michael R. Gau
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University
of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104,
USA
| | - Patrick J. Carroll
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University
of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104,
USA
| | | | - Neil C. Tomson
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University
of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104,
USA
| |
Collapse
|
8
|
Hertler PR, Kautzsch L, Touchton AJ, Wu G, Hayton TW. Metal-Metal-Bonded Fe 4 Clusters with Slow Magnetic Relaxation. Inorg Chem 2022; 61:9997-10005. [PMID: 35709487 DOI: 10.1021/acs.inorgchem.2c00865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reaction of FeBr2 with Li(N═CtBu2) (0.5 equiv) and Zn0 (2 equiv) results in the formation of the formally mixed-valent cluster [Fe4Br2(N═CtBu2)4] (1) in moderate yield. The subsequent reaction of 1 with Na(N═CtBu2) results in formation of [Fe4Br(N═CtBu2)5] (2), also in moderate yield. Both 1 and 2 were characterized by zero-field 57Fe Mössbauer spectroscopy, X-ray crystallography, and superconducting quantum interference device magnetometry. Their tetrahedral [Fe4]6+ cores feature short Fe-Fe interactions (ca. 2.50 Å). Additionally, both 1 and 2 display S = 7 ground states at room temperature and slow magnetic relaxation with zero-field relaxation barriers of Ueff = 14.7(4) and 15.6(7) cm-1, respectively. Moreover, AC magnetic susceptibility measurements were well modeled by assuming an Orbach relaxation process.
Collapse
Affiliation(s)
- Phoebe R Hertler
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Linus Kautzsch
- Materials Department and Materials Research Laboratory, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Alexander J Touchton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| |
Collapse
|
9
|
Kühne IA, Ozarowski A, Sultan A, Esien K, Carter AB, Wix P, Casey A, Heerah-Booluck M, Keene TD, Müller-Bunz H, Felton S, Hill S, Morgan GG. Homochiral Mn 3+ Spin-Crossover Complexes: A Structural and Spectroscopic Study. Inorg Chem 2022; 61:3458-3471. [PMID: 35175771 PMCID: PMC8889584 DOI: 10.1021/acs.inorgchem.1c03379] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Structural, magnetic,
and spectroscopic data on a Mn3+ spin-crossover complex
with Schiff base ligand 4-OMe-Sal2323, isolated in crystal
lattices with five different counteranions,
are reported. Complexes of [Mn(4-OMe-Sal2323)]X where X
= ClO4– (1), BF4– (2), NO3– (3), Br– (4), and I– (5) crystallize isotypically in the chiral
orthorhombic space group P21212 with a range of spin state preferences for the [Mn(4-OMe-Sal2323)]+ complex cation over the temperature range
5–300 K. Complexes 1 and 2 are high-spin,
complex 4 undergoes a gradual and complete thermal spin
crossover, while complexes 3 and 5 show
stepped crossovers with different ratios of spin triplet and quintet
forms in the intermediate temperature range. High-field electron paramagnetic
resonance was used to measure the zero-field splitting parameters
associated with the spin triplet and quintet states at temperatures
below 10 K for complexes 4 and 2 with respective
values: DS=1 = +23.38(1) cm–1, ES=1 = +2.79(1) cm–1,
and DS=2 =
+6.9(3) cm–1, with a distribution of E parameters for the S = 2 state. Solid-state circular
dichroism (CD) spectra on high-spin complex 1 at room
temperature reveal a 2:1 ratio of enantiomers in the chiral conglomerate,
and solution CD measurements on the same sample in methanol show that
it is stable toward racemization. Solid-state UV–vis absorption
spectra on high-spin complex 1 and mixed S = 1/S = 2 sample 5 reveal different
intensities at higher energies, in line with the different electronic
composition. The statistical prevalence of homochiral crystallization
of [Mn(4-OMe-Sal2323)]+ in five lattices with
different achiral counterions suggests that the chirality may be directed
by the 4-OMe-Sal2323 ligand. Zero-field
splitting parameters of the spin triplet and
quintet forms of a spin-crossover Mn3+ complex stabilized
in lattices with different counterions are measured by high-field
electron paramagnetic resonance at different frequencies. The homochiral
crystallization of the enantiopure Δ or Λ forms of the
chelate complex, despite the use of achiral anions, is attributed
to the steric influence of the ligand substituent.
Collapse
Affiliation(s)
- Irina A Kühne
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland.,FZU - Institute of Physics - Czech Academy of Sciences, Na Slovance 1999/2, Prague 8 182 21, Czech Republic
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Aizuddin Sultan
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland
| | - Kane Esien
- School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, United Kingdom
| | - Anthony B Carter
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland
| | - Paul Wix
- School of Chemistry & CRANN Institute & AMBER Centre, Trinity College Dublin, University of Dublin, College Green, Dublin 2, Ireland
| | - Aoife Casey
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland
| | | | - Tony D Keene
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland
| | - Helge Müller-Bunz
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland
| | - Solveig Felton
- School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, United Kingdom
| | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.,Department of Physics, Florida State University, Tallahassee, Florida 32306, United States
| | - Grace G Morgan
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland
| |
Collapse
|
10
|
Nicolini A, Affronte M, SantaLucia DJ, Borsari M, Cahier B, Caleffi M, Ranieri A, Berry JF, Cornia A. Tetrairon(II) extended metal atom chains as single-molecule magnets. Dalton Trans 2021; 50:7571-7589. [PMID: 33983354 PMCID: PMC8214398 DOI: 10.1039/d1dt01007g] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Iron-based extended metal atom chains (EMACs) are potentially high-spin molecules with axial magnetic anisotropy and thus candidate single-molecule magnets (SMMs). We herein compare the tetrairon(ii), halide-capped complexes [Fe4(tpda)3Cl2] (1Cl) and [Fe4(tpda)3Br2] (1Br), obtained by reacting iron(ii) dihalides with [Fe2(Mes)4] and N2,N6-di(pyridin-2-yl)pyridine-2,6-diamine (H2tpda) in toluene, under strictly anhydrous and anaerobic conditions (HMes = mesitylene). Detailed structural, electrochemical and Mössbauer data are presented along with direct-current (DC) and alternating-current (AC) magnetic characterizations. DC measurements revealed similar static magnetic properties for the two derivatives, with χMT at room temperature above that for independent spin carriers, but much lower at low temperature. The electronic structure of the iron(ii) ions in each derivative was explored by ab initio (CASSCF-NEVPT2-SO) calculations, which showed that the main magnetic axis of all metals is directed close to the axis of the chain. The outer metals, Fe1 and Fe4, have an easy-axis magnetic anisotropy (D = -11 to -19 cm-1, |E/D| = 0.05-0.18), while the internal metals, Fe2 and Fe3, possess weaker hard-axis anisotropy (D = 8-10 cm-1, |E/D| = 0.06-0.21). These single-ion parameters were held constant in the fitting of DC magnetic data, which revealed ferromagnetic Fe1-Fe2 and Fe3-Fe4 interactions and antiferromagnetic Fe2-Fe3 coupling. The competition between super-exchange interactions and the large, noncollinear anisotropies at metal sites results in a weakly magnetic non-Kramers doublet ground state. This explains the SMM behavior displayed by both derivatives in the AC susceptibility data, with slow magnetic relaxation in 1Br being observable even in zero static field.
Collapse
Affiliation(s)
- Alessio Nicolini
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia & INSTM, I-41125 Modena, Italy. and Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, I-41125 Modena, Italy
| | - Marco Affronte
- Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, I-41125 Modena, Italy
| | - Daniel J SantaLucia
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA
| | - Marco Borsari
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia & INSTM, I-41125 Modena, Italy.
| | - Benjamin Cahier
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Matteo Caleffi
- Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, I-41125 Modena, Italy
| | - Antonio Ranieri
- Department of Life Sciences, University of Modena and Reggio Emilia, I-41125 Modena, Italy
| | - John F Berry
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA
| | - Andrea Cornia
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia & INSTM, I-41125 Modena, Italy.
| |
Collapse
|
11
|
Nehrkorn J, Greer SM, Malbrecht BJ, Anderton KJ, Aliabadi A, Krzystek J, Schnegg A, Holldack K, Herrmann C, Betley TA, Stoll S, Hill S. Spectroscopic Investigation of a Metal-Metal-Bonded Fe 6 Single-Molecule Magnet with an Isolated S = 19/ 2 Giant-Spin Ground State. Inorg Chem 2021; 60:4610-4622. [PMID: 33683105 DOI: 10.1021/acs.inorgchem.0c03595] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The metal-metal-bonded molecule [Bu4N][(HL)2Fe6(dmf)2] (Fe6) was previously shown to possess a thermally isolated spin S = 19/2 ground state and found to exhibit slow magnetization relaxation below a blocking temperature of ∼5 K [J. Am. Chem. Soc. 2015, 137, 13949-13956]. Here, we present a comprehensive spectroscopic investigation of this unique single-molecule magnet (SMM), combining ultrawideband field-swept high-field electron paramagnetic resonance (EPR) with frequency-domain Fourier-transform terahertz EPR to accurately quantify the spin Hamiltonian parameters of Fe6. Of particular importance is the near absence of a 4th-order axial zero-field splitting term, which is known to arise because of quantum mechanical mixing of spin states on account of the relatively weak spin-spin (superexchange) interactions in traditional polynuclear SMMs such as the celebrated Mn12-acetate. The combined high-resolution measurements on both powder samples and an oriented single crystal provide a quantitative measure of the isolated nature of the spin ground state in the Fe6 molecule, as well as additional microscopic insights into factors that govern the quantum tunneling of its magnetization. This work suggests strategies for improving the performance of polynuclear SMMs featuring direct metal-metal bonds and strong ferromagnetic spin-spin (exchange) interactions.
Collapse
Affiliation(s)
- Joscha Nehrkorn
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.,Department of Chemistry, Institute for Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany.,Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195, United States.,Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Samuel M Greer
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.,Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Brian J Malbrecht
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Kevin J Anderton
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Azar Aliabadi
- Berlin Joint EPR Laboratory, Institut für Nanospektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Kekuléstraße 5, Berlin 12489, Germany
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Alexander Schnegg
- Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany.,Berlin Joint EPR Laboratory, Institut für Nanospektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Kekuléstraße 5, Berlin 12489, Germany
| | - Karsten Holldack
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialen und Energie, Albert-Einstein-Straße 15, Berlin 12489, Germany
| | - Carmen Herrmann
- Department of Chemistry, Institute for Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
| | - Theodore A Betley
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Stefan Stoll
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195, United States
| | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.,Department of Physics, Florida State University, Tallahassee 32306, Florida, United States
| |
Collapse
|