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Corner S, Gransbury GK, Vitorica-Yrezabal IJ, Whitehead GFS, Chilton NF, Mills DP. Halobenzene Adducts of a Dysprosocenium Single-Molecule Magnet. Inorg Chem 2024; 63:9552-9561. [PMID: 38359351 PMCID: PMC11134494 DOI: 10.1021/acs.inorgchem.3c04105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/18/2024] [Accepted: 01/23/2024] [Indexed: 02/17/2024]
Abstract
Dysprosium complexes with strong axial crystal fields are promising candidates for single-molecule magnets (SMMs), which could be used for high-density data storage. Isolated dysprosocenium cations, [Dy(CpR)2]+ (CpR = substituted cyclopentadienyl), have recently shown magnetic hysteresis (a memory effect) above the temperature of liquid nitrogen. Synthetic efforts have focused on reducing strong transverse ligand fields in these systems as they are known to enhance magnetic relaxation by spin-phonon mechanisms. Here we show that equatorial coordination of the halobenzenes PhX (X = F, Cl, Br) and o-C6H4F2 to the cation of a recently reported dysprosocenium complex [Dy(Cpttt)(Cp*)][Al{OC(CF3)3}4] (Cpttt = C5H2tBu3-1,2,4; Cp* = C5Me5) reduces magnetic hysteresis temperatures compared to that of the parent cation. We find that this is due to increased effectiveness of both one- (Orbach) and two-phonon (Raman) relaxation mechanisms, which correlate with the electronegativity and number of interactions with the halide despite κ1-coordination of a single halobenzene having a minimal effect on the metrical parameters of [Dy(Cpttt)(Cp*)(PhX-κ1-X)]+ cations vs the isolated [Dy(Cpttt)(Cp*)]+ cation. We observe unusual divergent behavior of relaxation rates at low temperatures in [Dy(Cpttt)(Cp*)(PhX)][Al{OC(CF3)3}4], which we attribute to a phonon bottleneck effect. We find that, despite the transverse fields introduced by the monohalobenzenes in these cations, the interactions are sufficiently weak that the effective barriers to magnetization reversal remain above 1000 cm-1, being only ca. 100 cm-1 lower than for the parent complex, [Dy(Cpttt)(Cp*)][Al{OC(CF3)3}4].
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Affiliation(s)
| | | | | | - George F. S. Whitehead
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | | | - David P. Mills
- Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
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2
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Augustinov W, Müller M, Thomas-Hargreaves LR, Ivlev SI, Buchner MR. Synthesis and Derivatives of Beryllium Triflate. Inorg Chem 2024; 63:5208-5219. [PMID: 38439511 DOI: 10.1021/acs.inorgchem.4c00198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2024]
Abstract
Various pathways for the synthesis of beryllium triflate were investigated. The reaction of triflic acid or trimethylsilyl triflate with beryllium metal in liquid ammonia led to the formation of mono-, di-, and tetra-nuclear beryllium ammine complexes. Utilization of SMe2 as a solvent gave homoleptic Be(OTf)2. Various beryllium triflate complexes with N- and O-donor ligands as well as the complex anions [Be(OTf)4]2- and [Be2(OTf)6]2- were synthesized to evaluate the reactivity and solution properties of beryllium triflate. This showed that OTf- is not a weakly coordinating anion for Be2+ cations and that it exhibits good bridging properties.
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Affiliation(s)
- William Augustinov
- Fachbereich Chemie, Philipps-Universität Marburg, Marburg 35032, Germany
| | - Matthias Müller
- Fachbereich Chemie, Philipps-Universität Marburg, Marburg 35032, Germany
| | | | - Sergei I Ivlev
- Fachbereich Chemie, Philipps-Universität Marburg, Marburg 35032, Germany
| | - Magnus R Buchner
- Fachbereich Chemie, Philipps-Universität Marburg, Marburg 35032, Germany
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3
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Trujillo-González DE, González-García G, Jiménez-Halla JOC, Solà M. Beryllium compounds for the carbon-halogen bond activation of phenyl halides: the role of non-innocent ligands. Dalton Trans 2023; 52:13068-13078. [PMID: 37700680 DOI: 10.1039/d3dt02251j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
Beryllium is a metallomimetic main-group element, i.e., it behaves similarly to transition metals (TMs) in some bond activation processes. To investigate the ability of Be compounds to activate C-X bonds (X = F-I), we have computationally investigated, using DFT methods, the reaction of (CAAC)2Be (CAAC = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) and a series of five-membered heterocyclic beryllium bidentate ligands with phenyl halides. We have analysed all plausible reaction mechanisms and our results show that, after the initial C-X oxidative addition, migration of the phenyl group occurs towards the less electronegative heteroatom. Our theoretical study highlights the important role of bidentate non-innocent ligands in providing the required electrons for the initial Ph-X oxidative addition. In contrast, the monodentate ligand, CAAC, does not favour this oxidative addition.
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Affiliation(s)
- Daniel E Trujillo-González
- Departamento de Química, Campus Guanajuato, Universidad de Guanajuato, Noria Alta S/N, CP 36050, Guanajuato, Gto, Mexico.
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/ Maria Aurèlia Capmany, 69, 17003 Girona, Catalonia, Spain.
| | - Gerardo González-García
- Departamento de Química, Campus Guanajuato, Universidad de Guanajuato, Noria Alta S/N, CP 36050, Guanajuato, Gto, Mexico.
| | - J Oscar C Jiménez-Halla
- Departamento de Química, Campus Guanajuato, Universidad de Guanajuato, Noria Alta S/N, CP 36050, Guanajuato, Gto, Mexico.
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/ Maria Aurèlia Capmany, 69, 17003 Girona, Catalonia, Spain.
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Boronski JT, Thomas-Hargreaves LR, Ellwanger MA, Crumpton AE, Hicks J, Bekiş DF, Aldridge S, Buchner MR. Inducing Nucleophilic Reactivity at Beryllium with an Aluminyl Ligand. J Am Chem Soc 2023; 145:4408-4413. [PMID: 36786728 PMCID: PMC9983009 DOI: 10.1021/jacs.3c00480] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
The reactions of anionic aluminium or gallium nucleophiles {K[E(NON)]}2 (E = Al, 1; Ga, 2; NON = 4,5-bis(2,6-diisopropylanilido)-2,7-ditert-butyl-9,9-dimethylxanthene) with beryllocene (BeCp2) led to the displacement of one cyclopentadienyl ligand at beryllium and the formation of compounds containing Be-Al or Be-Ga bonds (NON)EBeCp (E = Al, 3; Ga, 4). The Be-Al bond in the beryllium-aluminyl complex [2.310(4) Å] is much shorter than that found in the small number of previous examples [2.368(2) to 2.432(6) Å], and quantum chemical calculations suggest the existence of a non-nuclear attractor (NNA) for the Be-Al interaction. This represents the first example of a NNA for a heteroatomic interaction in an isolated molecular complex. As a result of this unusual electronic structure and the similarity in the Pauling electronegativities of beryllium and aluminium, the charge at the beryllium center (+1.39) in 3 is calculated to be less positive than that of the aluminium center (+1.88). This calculated charge distribution suggests the possibility for nucleophilic behavior at beryllium and correlates with the observed reactivity of the beryllium-aluminyl complex with N,N'-diisopropylcarbodiimide─the electrophilic carbon center of the carbodiimide undergoes nucleophilic attack by beryllium, thereby yielding a beryllium-diaminocarbene complex.
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Affiliation(s)
- Josef T. Boronski
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom;,
| | | | - Mathias A. Ellwanger
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom;
| | - Agamemnon E. Crumpton
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom;
| | - Jamie Hicks
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom;
| | - Deniz F. Bekiş
- Fachbereich
Chemie, Philipps-Universität Marburg, Marburg 35037, Germany
| | - Simon Aldridge
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom;,
| | - Magnus R. Buchner
- Fachbereich
Chemie, Philipps-Universität Marburg, Marburg 35037, Germany,
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5
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Davison N, Quirk JA, Wills C, Dixon C, Waddell PG, Dawson JA, Lu E. Elucidating Solution-State Coordination Modes of Multidentate Neutral Amine Ligands with Group-1 Metal Cations: Variable-Temperature NMR Studies. Inorg Chem 2022; 61:15204-15212. [PMID: 36109881 PMCID: PMC9516690 DOI: 10.1021/acs.inorgchem.2c02457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Multidentate neutral amine ligands play vital roles in
coordination
chemistry and catalysis. In particular, these ligands are used to
tune the reactivity of Group-1 metal reagents, such as organolithium
reagents. Most, if not all, of these Group-1 metal reagent-mediated
reactions occur in solution. However, the solution-state coordination
behaviors of these ligands with Group-1 metal cations are poorly understood,
compared to the plethora of solid-state structural studies based on
single-crystal X-ray diffraction (SCXRD) studies. In this work, we
comprehensively mapped out the coordination modes with Group-1 metal
cations for three multidentate neutral amine ligands: tridentate 1,4,7-trimethyl-1,4,7-triazacyclononane
(Me3TACN), tetradentate tris[2-(dimethylamino)ethyl]amine
(Me6Tren), and hexadentate N,N′,N″-tris-(2-N-diethylaminoethyl)-1,4,7-triaza-cyclononane
(DETAN). The macrocycles in the Me3TACN and DETAN are identified
as the rigid structural directing motif, with the sidearms of DETAN
providing flexible “on-demand” coordination sites. In
comparison, the Me6Tren ligand features more robust coordination,
with the sidearms less likely to undergo the decoordinating–coordinating
equilibrium. This work will provide a guidance for coordination chemists
in applying these three ligands, in particular, the new DETAN ligand
to design metal complexes which suit their purposes. Combining variable-temperature nuclear
magnetic resonance
(VT NMR) and DFT calculations, this work elucidates the solution-state
coordination modes of three multidentate neutral amine ligands with
Group-1 metal cations. Our studies prove that two ligand-design building
blocks, that is, N-macrocycle (TACN) and N-sidearms, act as structure-dictating
and hemilabile coordinating sites, respectively. The concept could
be utilized in designing new catalytic systems, which anchor the metal
center on the macrocycle, while the sidearms serve as “on-demand”
protective coordination sites.
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Affiliation(s)
- Nathan Davison
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - James A. Quirk
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Corinne Wills
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Casey Dixon
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Paul G. Waddell
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - James A. Dawson
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Erli Lu
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
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6
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Buchner MR, Spang N, Ivlev SI. Hydrolysis and oxidation products of phosphine adducts to beryllium chloride. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2022. [DOI: 10.1515/znb-2022-0015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The synthesis of bis(diphenylphosphino)ethane (dppe) and PMe3 mono-adducts [(dppe)BeCl2]n and [(PMe3)BeCl2]2 is described and their spectroscopic properties discussed. Hydrolysis of these two compounds and of the bis(diphenylphosphino)propane (dppp) adduct to BeCl2 gave [dppeH2][BeCl4], [Me3PH]n[Be4Cl9]n and [dpppH2][Be2Cl6], which have been isolated and structurally characterized by single crystal X-ray diffraction. The reactions of [(PMe3)BeCl2]2 with p-cresole gave [Me3PH]2[Be2Cl4(OC7H7)2]. This phenoxide together with [(Me3PO)2Be2Cl4], the oxidation product of [(PMe3)BeCl2]2, have also been structurally characterized.
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Affiliation(s)
- Magnus R. Buchner
- Fachbereich Chemie , Philipps-Universität Marburg , Hans-Meerwein-Straße 4, 35032 Marburg , Germany
| | - Nils Spang
- Fachbereich Chemie , Philipps-Universität Marburg , Hans-Meerwein-Straße 4, 35032 Marburg , Germany
| | - Sergei I. Ivlev
- Fachbereich Chemie , Philipps-Universität Marburg , Hans-Meerwein-Straße 4, 35032 Marburg , Germany
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