1
|
Ritschel C, Donsbach C, Feldmann C. Reactive Magnesium Nanoparticles to Perform Reactions in Suspension. Chemistry 2024; 30:e202400418. [PMID: 38593253 DOI: 10.1002/chem.202400418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/27/2024] [Accepted: 04/09/2024] [Indexed: 04/11/2024]
Abstract
Zerovalent magnesium (Mg(0)) nanoparticles are prepared in the liquid phase (THF) by reduction of MgBr2 either with lithium naphthalenide ([LiNaph]) or lithium biphenyl ([LiBP]). [LiBP]-driven reduction results in smaller Mg(0) nanoparticles (10.3±1.7 nm) than [LiNaph]-driven reduction (28.5±4 nm). The as-prepared Mg(0) nanoparticles are monocrystalline (d101=245±5 pm) for both types of reduction. Their reactivity is probed by liquid-phase reaction (THF, toluene) in suspension near room temperature (20-120 °C) with 1-bromoadamantane (AdBr), chlortriphenylsilane (Ph3SiCl), trichlorphenylsilane (PhSiCl3), 9H-carbazole (Hcbz), 7-azaindole (Hai), 1,8-diaminonaphthalene (H4nda) and N,N'-bis(α-pyridyl)-2,6-diaminopyridine (H2tpda) as exemplary starting materials. The reactions result in the formation of 1,1'-biadamantane (1), [MgCl2(thf)2]×Ph6Si2 (2), [Mg9(thf)14Cl18] (3), [Mg(cbz)2(thf)3] (4), [Mg4O(ai)6]×1.5 C7H8 (5), [Mg4(H2nda)4(thf)4] (6) and [Mg3(tpda)3] (7) with 40-80 % yield. 1 and 2 show the reactivity of Mg(0) nanoparticles for C-C and Si-Si coupling reactions with sterically demanding starting materials. 3-7 represent new coordination compounds using sterically demanding N-H-acidic amines as starting materials. The formation of multinuclear Mg2+ complexes with multidentate ligands illustrates the potential of the oxidative approach to obtain novel compounds with Mg(0) nanoparticles in the liquid phase.
Collapse
Affiliation(s)
- Christian Ritschel
- Institut für Anorganische Chemie, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131, Karlsruhe, Germany
| | - Carsten Donsbach
- Institut für Anorganische Chemie, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131, Karlsruhe, Germany
| | - Claus Feldmann
- Institut für Anorganische Chemie, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131, Karlsruhe, Germany
| |
Collapse
|
2
|
Damoc M, Tiron V, Tugui C, Varganici CD, Stoica AC, Novitchi G, Dascalu M, Cazacu M. Ferronematic Co(II) Complex: An Active Filler for Magnetically Actuated Soft Materials. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2307006. [PMID: 37992252 DOI: 10.1002/smll.202307006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 11/08/2023] [Indexed: 11/24/2023]
Abstract
Ferronematics that are generally based on nematic liquid crystals (LCs) doped with magnetic nanoparticles, synergistically taking advantage of the anisotropic and flow characteristics of the nematic host and the magnetic susceptibility of the dopant, have powerful applications as magnetically actuated soft materials. In this work, a Co(II) complex, which alone presents both characteristics, is built with a salen-type ligand 3,5-dichlorosubstituted at the aromatic nuclei and has a tetramethyldisiloxane spacer, which makes it one of the few metallomesogens containing this structural motif. Paramagnetic crystals, through heat treatment above 110 °C, change into magnetic nematic LCs. Applying a perpendicular magnetic field of 50 mT, the nematic droplets align two by two through dipole-dipole interactions. By incorporating it into a silicone matrix consisting mainly of polydimethylsiloxane, a 3D printable ink is formulated and crosslinked under various shapes. In this environment, the cobalt complex is stabilized in an LC state at room temperature and, due to its anisotropy, facilitates the mechanical response to magnetic stimuli. The resulting objects can be easily manipulated on fluid or rough surfaces using external magnetic fields, behave like magnets by themselves, and show reversible locomotion.
Collapse
Affiliation(s)
- Madalin Damoc
- Department of Inorganic Polymers, "Petru Poni" Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi, 700487, Romania
| | - Vasile Tiron
- Research Center on Advanced Materials and Technologies, Department of Exact and Natural Sciences, Institute of Interdisciplinary Research, Alexandru Ioan Cuza University of Iasi, Blvd. Carol no. 11, Iasi, 700506, Romania
| | - Codrin Tugui
- Department of Inorganic Polymers, "Petru Poni" Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi, 700487, Romania
| | - Cristian-Dragos Varganici
- Centre of Advanced Research in Bionanoconjugates and Biopolymers, "Petru Poni" Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi, 700487, Romania
| | - Alexandru-Constantin Stoica
- Department of Inorganic Polymers, "Petru Poni" Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi, 700487, Romania
| | - Ghenadie Novitchi
- Laboratoire National des Champs Magnétiques Intenses, CNRS UPR 3228, 25 Rue des Martyrs, Grenoble, 38042, France
| | - Mihaela Dascalu
- Department of Inorganic Polymers, "Petru Poni" Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi, 700487, Romania
| | - Maria Cazacu
- Department of Inorganic Polymers, "Petru Poni" Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi, 700487, Romania
| |
Collapse
|
3
|
Pilar Del Río M, Villarroya BE, López JA, Geer AM, Lahoz FJ, Ciriano MA, Tejel C. Mixed-Valence Tetrametallic Iridium Chains. Chemistry 2023; 29:e202301438. [PMID: 37402228 DOI: 10.1002/chem.202301438] [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: 05/05/2023] [Revised: 07/04/2023] [Accepted: 07/04/2023] [Indexed: 07/06/2023]
Abstract
Neutral [X-{Ir2 }-{Ir2 }-X] (X=Cl, Br, SCN, I) and dicationic [L-{Ir2 }-{Ir2 }-L]2+ (L=MeCN, Me2 CO) tetrametallic iridium chains made by connecting two dinuclear {Ir2 } units ({Ir2 }=[Ir2 (μ-OPy)2 (CO)4 ], OPy=2-pyridonate) by an iridium-iridium bond are described. The complexes exhibit fractional averaged oxidation states of +1.5 and electronic delocalization along the metallic chain. While the axial ligands do not significantly affect the metal-metal bond lengths, the metallic chain has a significant impact on the iridium-L/X bond distances. The complexes show free rotation around the unsupported iridium-iridium bond in solution, with a low-energy transition state for the chloride chain. The absorption spectra of these complexes show characteristic bands at 438-504 nm, which can be fine-tuned by varying the terminal capping ligands.
Collapse
Affiliation(s)
- M Pilar Del Río
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, Facultad de Ciencias, 50009, Zaragoza, Spain
| | - B Eva Villarroya
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, Facultad de Ciencias, 50009, Zaragoza, Spain
| | - José A López
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, Facultad de Ciencias, 50009, Zaragoza, Spain
| | - Ana M Geer
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, Facultad de Ciencias, 50009, Zaragoza, Spain
| | - Fernando J Lahoz
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, Facultad de Ciencias, 50009, Zaragoza, Spain
| | - Miguel A Ciriano
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, Facultad de Ciencias, 50009, Zaragoza, Spain
| | - Cristina Tejel
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, Facultad de Ciencias, 50009, Zaragoza, Spain
| |
Collapse
|
4
|
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
|
5
|
Govindarajan R, Deolka S, Khusnutdinova JR. Heterometallic bond activation enabled by unsymmetrical ligand scaffolds: bridging the opposites. Chem Sci 2022; 13:14008-14031. [PMID: 36540828 PMCID: PMC9728565 DOI: 10.1039/d2sc04263k] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 10/27/2022] [Indexed: 08/19/2023] Open
Abstract
Heterobi- and multimetallic complexes providing close proximity between several metal centers serve as active species in artificial and enzymatic catalysis, and in model systems, showing unique modes of metal-metal cooperative bond activation. Through the rational design of well-defined, unsymmetrical ligand scaffolds, we create a convenient approach to support the assembly of heterometallic species in a well-defined and site-specific manner, preventing them from scrambling and dissociation. In this perspective, we will outline general strategies for the design of unsymmetrical ligands to support heterobi- and multimetallic complexes that show reactivity in various types of heterometallic cooperative bond activation.
Collapse
Affiliation(s)
- R Govindarajan
- Coordination Chemistry and Catalysis Unit, Okinawa Institute of Science and Technology Graduate University 1919-1 Tancha, Onna-son 904-0495 Okinawa Japan
| | - Shubham Deolka
- Coordination Chemistry and Catalysis Unit, Okinawa Institute of Science and Technology Graduate University 1919-1 Tancha, Onna-son 904-0495 Okinawa Japan
| | - Julia R Khusnutdinova
- Coordination Chemistry and Catalysis Unit, Okinawa Institute of Science and Technology Graduate University 1919-1 Tancha, Onna-son 904-0495 Okinawa Japan
| |
Collapse
|
6
|
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
|
7
|
Structural Diversity of Lithium Oligo-α-Pyridylamides. CHEMISTRY 2022. [DOI: 10.3390/chemistry4020037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Lithium oligo-α-pyridylamides are useful intermediates in coordination chemistry. Upon trans-metalation they have afforded a variety of extended metal atom chains (EMACs), which are currently investigated as molecular wires and single-molecule magnets. However, structural information on this class of compounds is scarce. Two trilithium salts of a new, sterically encumbered oligo-α-pyridylamido ligand were isolated in crystalline form and structurally characterized in the solid state and in solution. Lithiation of N2-(trimethylsilyl)-N6-{6-[(trimethylsilyl)amino]pyridin-2-yl}pyridine-2,6-diamine (H3L) with n-BuLi in thf yielded dimeric adduct [Li6L2(thf)6] (1), which was crystallized from n-hexane/thf as 1·C6H14. Crystals of a tetra-thf solvate with formula [Li6L2(thf)4] (2) were also obtained. The compounds feature two twisted L3− ligands exhibiting a cis-cis conformation and whose five nitrogen donors are all engaged in metal coordination. The six Li+ ions per molecule display coordination numbers ranging from 3 to 5. Compound 1·C6H14 was investigated by multinuclear 1D and 2D NMR spectroscopy, including 1H DOSY experiments, which indicated retention of the dimeric structure in benzene-d6 solution. To the best of our knowledge, 1 and 2 are the longest-chain lithium oligo-α-pyridylamides structurally authenticated so far, thereby qualifying as appealing intermediates to access high-nuclearity EMACs by trans-metalation.
Collapse
|
8
|
Wu MY, Xu JX, Chen YH, Lu IC, Han JL, Lin PH. Self-assembled lanthanide-based helixes: synthetic control of the helical handedness by chirality of the ligand. Dalton Trans 2021; 51:69-73. [PMID: 34897306 DOI: 10.1039/d1dt03833h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The control of the self-assembly of lanthanide helical chain and their helical handedness have been investigated for the first time. Δ- and Λ-form lanthanide chain complexes were obtained by introducing thiazolidine ligands that were synthesised from L- and D-cysteine, respectively, and shared the same formula: [Ln2(L)3(H2O)5]∞·3H2O (Ln: Sm and Eu) (L: 2-(2-hydroxy-3,5-dinitrophenyl)thiazolidine-4-carboxylic acid). The crystallographic, circular dichroism, and luminescence properties of these novel lanthanide chain complexes were studied.
Collapse
Affiliation(s)
- Min-Yu Wu
- Department of Chemistry, National Chung Hsing University, 250 Kuo Kuang Rd., Taichung 402, Taiwan.
| | - Jing-Xiang Xu
- Department of Chemistry, National Chung Hsing University, 250 Kuo Kuang Rd., Taichung 402, Taiwan.
| | - Yi-Hsin Chen
- Department of Chemistry, National Chung Hsing University, 250 Kuo Kuang Rd., Taichung 402, Taiwan.
| | - I-Chung Lu
- Department of Chemistry, National Chung Hsing University, 250 Kuo Kuang Rd., Taichung 402, Taiwan.
| | - Jeng-Liang Han
- Department of Chemistry, National Chung Hsing University, 250 Kuo Kuang Rd., Taichung 402, Taiwan.
| | - Po-Heng Lin
- Department of Chemistry, National Chung Hsing University, 250 Kuo Kuang Rd., Taichung 402, Taiwan.
| |
Collapse
|
9
|
Srinivasan A, Musgrave RA, Rouzières M, Clérac R, McGrady JE, Hillard EA. A linear metal-metal bonded tri-iron single-molecule magnet. Chem Commun (Camb) 2021; 57:13357-13360. [PMID: 34821230 DOI: 10.1039/d1cc05043e] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The linear trinuclear complex cation [Fe3(DpyF)4]2+ was prepared as [Fe3(DpyF)4](BF4)2·2CH3CN. With large Fe-Fe distances of 2.78 Å, this complex demonstrates intramolecular ferromagnetic coupling between the anisotropic FeII centers (J/kB = +20.9(5) K) giving an ST = 6 ground state and exhibits single-molecule magnet properties.
Collapse
Affiliation(s)
- Anandi Srinivasan
- Univ. Bordeaux, CNRS, Centre de Recherche Paul Pascal, UMR 5031, Pessac, F-33600, France.
| | - Rebecca A Musgrave
- Univ. Bordeaux, CNRS, Centre de Recherche Paul Pascal, UMR 5031, Pessac, F-33600, France.
| | - Mathieu Rouzières
- Univ. Bordeaux, CNRS, Centre de Recherche Paul Pascal, UMR 5031, Pessac, F-33600, France.
| | - Rodolphe Clérac
- Univ. Bordeaux, CNRS, Centre de Recherche Paul Pascal, UMR 5031, Pessac, F-33600, France.
| | - John E McGrady
- Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK
| | - Elizabeth A Hillard
- Univ. Bordeaux, CNRS, Centre de Recherche Paul Pascal, UMR 5031, Pessac, F-33600, France.
| |
Collapse
|
10
|
Uemura K, Yasuda E, Sugiyama Y. Improving the Solubility of Hexanuclear Heterometallic Extended Metal Atom Chain Compounds in Nonpolar Solvents by Introducing Alkyl Amine Moieties. ACS OMEGA 2021; 6:18487-18503. [PMID: 34308079 PMCID: PMC8296546 DOI: 10.1021/acsomega.1c02634] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
The highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) interaction at the d z 2 orbital between two kinds of metal complex is useful for obtaining heterometallic one-dimensional (1D) chains as well as heterometallic metal string compounds (HMSCs). Platinum dinuclear complexes, [Pt2(piam)2(NH2R)4]X2 (piam = pivalamidate, R = CH3, C2H5, C3H7, or C4H9, X = anion), comprising σ* as HOMO were mixed with [Rh2(O2CCH3)4] comprising σ* as LUMO in solvents to afford single crystals of [{Rh2(O2CCH3)4}{Pt2(piam)2(NH2R)4}2]X4 (2-5). Single-crystal X-ray analyses revealed that 2-5 are hexanuclear complexes that are one-dimensionally aligned as Pt-Pt-Rh-Rh-Pt-Pt with metal-metal bonds, where the alkyl moieties at end Pt atoms obstruct further 1D extension. Complexes 2-5 appear as if they are cut off from an infinite chain [{Rh2(O2CCH3)4}{Pt2(piam)2(NH3)4}2] n (PF6)4n ·6nH2O (1) aligned as -{Pt-Pt-Rh-Rh-Pt-Pt} n -. The diffuse reflectance spectrum of 1 depicts broad shoulder bands, which are not present in the spectra of 2-5, proving that the infinite chain 1 forms a band structure. Compounds 4 and 5 with propyl or butyl moieties at amine ligands, respectively, are soluble in nonpolar solvents, such as CH2Cl2, without the dissociation of their hexanuclear structures. Taking advantage of their solubility, measurement of cyclic voltammetry in CH2Cl2 become possible, which shows the quasi-reversible oxidation and reduction waves at 4: E ox = 0.86 V and E red = 0.69 V and 5: E ox = 0.87 V and E red = 0.53 V.
Collapse
|
11
|
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
|
12
|
Chakarawet K, Atanasov M, Marbey J, Bunting PC, Neese F, Hill S, Long JR. Strong Electronic and Magnetic Coupling in M 4 (M = Ni, Cu) Clusters via Direct Orbital Interactions between Low-Coordinate Metal Centers. J Am Chem Soc 2020; 142:19161-19169. [PMID: 33111523 DOI: 10.1021/jacs.0c08460] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present an extensive study of tetranuclear transition-metal cluster compounds M4(NPtBu3)4 and [M4(NPtBu3)4][B(C6F5)4] (M = Ni, Cu; tBu = tert-butyl), which feature low-coordinate metal centers and direct metal-metal orbital overlap. X-ray diffraction, electrochemical, magnetic, spectroscopic, and computational analysis elucidate the nature of the bonding interactions in these clusters and the impact of these interactions on the electronic and magnetic properties. Direct orbital overlap results in strongly coupled, large-spin ground states in the [Ni4(NPtBu3)4]+/0 clusters and fully delocalized, spin-correlated electrons. Correlated electronic structure calculations confirm the presence of ferromagnetic ground states that arise from direct exchange between magnetic orbitals, and, in the case of the neutral cluster, itinerant electron magnetism similar to that in metallic ferromagnets. The cationic nickel cluster also possesses large magnetic anisotropy exemplified by a large, positive axial zero-field splitting parameter of D = +7.95 or +9.2 cm-1, as determined by magnetometry or electron paramagnetic resonance spectroscopy, respectively. The [Ni4(NPtBu3)4]+ cluster is also the first molecule with easy-plane magnetic anisotropy to exhibit zero-field slow magnetic relaxation, and under a small applied field, it exhibits relaxation exclusively through an Orbach mechanism with a spin relaxation barrier of 16 cm-1. The S = 1/2 complex [Cu4(NPtBu3)4]+ exhibits slow magnetic relaxation via a Raman process on the millisecond time scale, supporting the presence of slow relaxation via an Orbach process in the nickel analogue. Overall, this work highlights the unique electronic and magnetic properties that can be realized in metal clusters featuring direct metal-metal orbital interactions between low-coordinate metal centers.
Collapse
Affiliation(s)
| | - Mihail Atanasov
- Max-Planck Institut für Kohlenforschung, Mülheim an der Ruhr D-45470, Germany.,Institute of General and Inorganic Chemistry, Bulgarian Academy of Science, Akad. Georgi Bontchev, Street 11, 1113 Sofia, Bulgaria
| | - Jonathan Marbey
- Department of Physics and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | | | - Frank Neese
- Max-Planck Institut für Kohlenforschung, Mülheim an der Ruhr D-45470, Germany
| | - Stephen Hill
- Department of Physics and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Jeffrey R Long
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| |
Collapse
|
13
|
Guillet GL, Arpin KY, Boltin AM, Gordon JB, Rave JA, Hillesheim PC. Synthesis and Characterization of a Linear Triiron(II) Extended Metal Atom Chain Complex with Fe–Fe Bonds. Inorg Chem 2020; 59:11238-11243. [DOI: 10.1021/acs.inorgchem.0c01625] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gary L. Guillet
- Department of Chemistry and Biochemistry, Georgia Southern University, 11935 Abercorn Street, Savannah, Georgia 31419, United States
| | - Kathleen Y. Arpin
- Department of Chemistry and Biochemistry, Georgia Southern University, 11935 Abercorn Street, Savannah, Georgia 31419, United States
| | - Alan M. Boltin
- Department of Chemistry and Biochemistry, Georgia Southern University, 11935 Abercorn Street, Savannah, Georgia 31419, United States
| | - Jesse B. Gordon
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Justin A. Rave
- Department of Chemistry and Biochemistry, Georgia Southern University, 11935 Abercorn Street, Savannah, Georgia 31419, United States
| | - Patrick C. Hillesheim
- Department of Chemistry and Physics, Ave Maria University, 5050 Ave Maria Boulevard, Ave Maria, Florida 34142, United States
| |
Collapse
|
14
|
Abstract
Significant progress has been made in the past 10-15 years on the design, synthesis, and properties of multimetallic coordination complexes with heterometallic metal-metal bonds that are paramagnetic. Several general classes have been explored including heterobimetallic compounds, heterotrimetallic compounds of either linear or triangular geometry, discrete molecular compounds containing a linear array of more than three metal atoms, and coordination polymers with a heterometallic metal-metal bonded backbone. We focus in this Review on the synthetic methods employed to access these compounds, their structural features, magnetic properties, and electronic structure. Regarding the metal-metal bond distances, we make use of the formal shortness ratio (FSR) for comparison of bond distances between a broad range of metal atoms of different sizes. The magnetic properties of these compounds can be described using an extension of the Goodenough-Kanamori rules to cases where two magnetic ions interact via a third metal atom. In describing the electronic structure, we focus on the ability (or not) of electrons to be delocalized across heterometallic bonds, allowing for rationalizations and predictions of single-molecule conductance measurements in paramagnetic heterometallic molecular wires.
Collapse
Affiliation(s)
- Jill A Chipman
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison Wisconsin 53706, United States
| | - John F Berry
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison Wisconsin 53706, United States
| |
Collapse
|
15
|
Cornia A, Barra AL, Bulicanu V, Clérac R, Cortijo M, Hillard EA, Galavotti R, Lunghi A, Nicolini A, Rouzières M, Sorace L, Totti F. The Origin of Magnetic Anisotropy and Single-Molecule Magnet Behavior in Chromium(II)-Based Extended Metal Atom Chains. Inorg Chem 2020; 59:1763-1777. [PMID: 31967457 PMCID: PMC7901656 DOI: 10.1021/acs.inorgchem.9b02994] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Indexed: 02/08/2023]
Abstract
Chromium(II)-based extended metal atom chains have been the focus of considerable discussion regarding their symmetric versus unsymmetric structure and magnetism. We have now investigated four complexes of this class, namely, [Cr3(dpa)4X2] and [Cr5(tpda)4X2] with X = Cl- and SCN- [Hdpa = dipyridin-2-yl-amine; H2tpda = N2,N6-di(pyridin-2-yl)pyridine-2,6-diamine]. By dc/ac magnetic techniques and EPR spectroscopy, we found that all these complexes have easy-axis anisotropies of comparable magnitude in their S = 2 ground state (|D| = 1.5-1.8 cm-1) and behave as single-molecule magnets at low T. Ligand-field and DFT/CASSCF calculations were used to explain the similar magnetic properties of tri- versus pentachromium(II) strings, in spite of their different geometrical preferences and electronic structure. For both X ligands, the ground structure is unsymmetric in the pentachromium(II) species (i.e., with an alternation of long and short Cr-Cr distances) but is symmetric in their shorter congeners. Analysis of the electronic structure using quasi-restricted molecular orbitals (QROs) showed that the four unpaired electrons in Cr5 species are largely localized in four 3d-like QROs centered on the terminal, "isolated" Cr2+ ion. In Cr3 complexes, they occupy four nonbonding combinations of 3d-like orbitals centered only on the two terminal metals. In both cases, then, QRO eigenvalues closely mirror the 3d-level pattern of the terminal ions, whose coordination environment remains quite similar irrespective of chain length. We conclude that the extent of unpaired-electron delocalization has little impact on the magnetic anisotropy of these wire-like molecular species.
Collapse
Affiliation(s)
- Andrea Cornia
- Department of Chemical and Geological Sciences,
University of Modena and Reggio Emilia & INSTM, 41125
Modena, Italy
| | - Anne-Laure Barra
- Laboratoire National des Champs Magnétiques
Intenses-CNRS, Université Grenoble-Alpes, 38042 Grenoble
Cedex 9, France
| | - Vladimir Bulicanu
- Univ. Bordeaux, CNRS, Centre de Recherche
Paul Pascal, CRPP, UMR 5031, 33600 Pessac, France
| | - Rodolphe Clérac
- Univ. Bordeaux, CNRS, Centre de Recherche
Paul Pascal, CRPP, UMR 5031, 33600 Pessac, France
| | - Miguel Cortijo
- Univ. Bordeaux, CNRS, Centre de Recherche
Paul Pascal, CRPP, UMR 5031, 33600 Pessac, France
| | - Elizabeth A. Hillard
- Univ. Bordeaux, CNRS, Centre de Recherche
Paul Pascal, CRPP, UMR 5031, 33600 Pessac, France
| | - Rita Galavotti
- Department of Chemical and Geological Sciences,
University of Modena and Reggio Emilia & INSTM, 41125
Modena, Italy
| | - Alessandro Lunghi
- School of Physics and CRANN Institute,
Trinity College Dublin, Dublin 2,
Ireland
| | - Alessio Nicolini
- Department of Chemical and Geological Sciences,
University of Modena and Reggio Emilia & INSTM, 41125
Modena, Italy
- Department of Physics, Informatics, and Mathematics,
University of Modena and Reggio Emilia, 41125 Modena,
Italy
| | - Mathieu Rouzières
- Univ. Bordeaux, CNRS, Centre de Recherche
Paul Pascal, CRPP, UMR 5031, 33600 Pessac, France
| | - Lorenzo Sorace
- Department of Chemistry “Ugo Schiff”,
University of Florence & INSTM, 50019 Sesto Fiorentino
(FI), Italy
| | - Federico Totti
- Department of Chemistry “Ugo Schiff”,
University of Florence & INSTM, 50019 Sesto Fiorentino
(FI), Italy
| |
Collapse
|