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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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Huo R, Armstrong AJ, Nelmes GR, Lawes DJ, Edwards AJ, McMullin CL, Hicks J. Stabilisation of the [SiH 6] 2- Anion within a Supramolecular Assembly. Chemistry 2024; 30:e202400662. [PMID: 38376067 DOI: 10.1002/chem.202400662] [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: 02/20/2024] [Accepted: 02/20/2024] [Indexed: 02/21/2024]
Abstract
The hypercoordinate [SiH6]2- anion is not stable in solution. Here, we report the room temperature, solution stable molecular [SiH6]2- complex, [{KCa(NON)(OEt2)}2][SiH6] (NON=4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethyl-xanthene)), where the [SiH6]2- anion is stabilised within a supramolecular assembly that mimics the solid-state environment of the anion in the lattice of K2SiH6. Solution-state reactivity of the complex towards carbon monoxide, benzaldehyde, azobenzene and acetonitrile is reported, yielding a range of reduction and C-C coupled products.
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Affiliation(s)
- Ryan Huo
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| | - Alicia J Armstrong
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| | - Gareth R Nelmes
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| | - Douglas J Lawes
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| | - Alison J Edwards
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Claire L McMullin
- Department of Chemistry, University of Bath Claverton Down, Bath, BA2 7AY, United Kingdom
| | - Jamie Hicks
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
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3
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Nguyen DT, Helling C, Evans MJ, Jones C. Enforcing Metal-Arene Interactions in Bulky p-Terphenyl Bis(anilide) Complexes of Group 2 Metals (Be-Ba): Potential Precursors for Low-Oxidation-State Alkaline Earth Metal Systems. Inorg Chem 2024; 63:5718-5726. [PMID: 38471088 DOI: 10.1021/acs.inorgchem.4c00207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
An extremely bulky p-terphenyl bis(aniline), p-C6H4{C6H4[N(H)TCHP]-2}2 (TCHP = 2,4,6-tricyclohexylphenyl) TCHPTerphH2, has been developed. Deprotonation of a less bulky analogue, DipTerphH2 (Dip = 2,6-diisopropylphenyl), with BePh2 affords the bimetallic system, [(BePh)2(μ-DipTerph)] 1. Treating either TCHPTerphH2 or DipTerphH2 with Mg{CH2(SiMe3)}2 gives the monomeric bis(anilide) complexes [Mg(ArTerph)] (Ar = Dip 2, TCHP 3) which display rare examples of η6-arene coordination to the metal center. Treating 2 with THF leads to partial dissociation of the Mg···arene interaction and formation of [Mg(DipTerph)(THF)] 4. Reactions of the bis(aniline)s with the group 2 metal amides [M{N(SiMe3)2}2] afford dimeric, structurally analogous compounds [{M(ArTerph)}2] (Ar = Dip, M = Ca 5, Sr 6, Ba 7; Ar = TCHP, M = Ca 8, Sr 9, Ba 10) which display intermolecular M···arene interactions in the solid state. Computational studies have shown that the intramolecular M···η6-arene interactions in models of the ether-free metal bis(anilide) compounds are largely electrostatic in nature. Reductions of these compounds with alkali metals led to mixtures of unidentified products.
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Affiliation(s)
- Dat T Nguyen
- School of Chemistry, Monash University, P.O. Box 23, Melbourne 3800, Victoria, Australia
| | - Christoph Helling
- School of Chemistry, Monash University, P.O. Box 23, Melbourne 3800, Victoria, Australia
| | - Matthew J Evans
- School of Chemistry, Monash University, P.O. Box 23, Melbourne 3800, Victoria, Australia
| | - Cameron Jones
- School of Chemistry, Monash University, P.O. Box 23, Melbourne 3800, Victoria, Australia
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4
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Mondal R, Evans MJ, Nguyen DT, Rajeshkumar T, Maron L, Jones C. Steric control of Mg-Mg bond formation vs. N 2 activation in the reduction of bulky magnesium diamide complexes. Chem Commun (Camb) 2024; 60:1016-1019. [PMID: 38170497 DOI: 10.1039/d3cc05787a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Reduction of the magnesium(II) diamide [Mg(TripNON)] (TripNON = 4,5-bis(2,4,6-triisopropylanilido)-2,7-diethyl-9,9-dimethyl-xanthene) with 5% w/w K/KI leads to a good yield of a dianionic dimagnesium(I) species, as its potassium salt, [{K(TripNON)Mg}2]. An X-ray crystallographic analysis shows the molecule to contain a very long Mg-Mg bond (3.137(2) Å). The formation of [{K(TripNON)Mg}2] contrasts with a previously reported reduction of a magnesium(II) complex incorporating a bulkier diamide ligand, which instead afforded a magnesium-dinitrogen complex. In the current study, [{K(TripNON)Mg}2] has been shown to be a viable reagent for the reductive activation of CO, H2 and N2O.
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Affiliation(s)
- Rahul Mondal
- School of Chemistry, Monash University, PO Box 23, Melbourne, VIC, 3800, Australia
| | - Matthew J Evans
- School of Chemistry, Monash University, PO Box 23, Melbourne, VIC, 3800, Australia
| | - Dat T Nguyen
- School of Chemistry, Monash University, PO Box 23, Melbourne, VIC, 3800, Australia
| | - Thayalan Rajeshkumar
- Université de Toulouse et CNRS, INSA, UPS, UMR5215, LPCNO, 135 Avenue de Rangueil, Toulouse 31077, France.
| | - Laurent Maron
- Université de Toulouse et CNRS, INSA, UPS, UMR5215, LPCNO, 135 Avenue de Rangueil, Toulouse 31077, France.
| | - Cameron Jones
- School of Chemistry, Monash University, PO Box 23, Melbourne, VIC, 3800, Australia
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Vasanthakumar A, Price JS, Emslie DJH. Rare earth dialkyl cations and monoalkyl dications supported by a rigid neutral pincer ligand: synthesis and ethylene polymerization. Chem Sci 2023; 14:8514-8523. [PMID: 37592999 PMCID: PMC10430518 DOI: 10.1039/d3sc01830j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 07/15/2023] [Indexed: 08/19/2023] Open
Abstract
A palladium-catalyzed coupling reaction between 4,5-dibromo-2,7-di-tert-butyl-9,9-dimethylxanthene and 2 equiv. of 1,3-diisopropylimidazolin-2-imine afforded the rigid neutral 2,7-di-tert-butyl-4,5-bis(1,3-diisopropylimidazolin-2-imino)-9,9-dimethylxanthene (XII2) pincer ligand. Reaction of XII2 with YCl3(THF)3.5 provided [(XII2)YCl3] (1). However, compound 1 failed to react cleanly with 3 equiv. of LiCH2SiMe3, and the reaction of XII2 with [Y(CH2SiMe3)3(THF)2] afforded a complex mixture of products. To access group 3 alkyl complexes without the intermediacy of [(XII2)M(CH2SiMe3)3], the XII2 ligand was protonated using [H(OEt2)2][B(C6F5)4] to form [H(XII2)][B(C6F5)4], and subsequent reaction with [M(CH2SiMe3)3(THF)2] (M = Y, Sc) directly afforded the cationic scandium and yttrium dialkyl complexes [(XII2)M(CH2SiMe3)2][B(C6F5)4] {M = Y (2) and Sc (3)}. Reaction of 3 with B(C6F5)3 in C6D5Br afforded dicationic [(XII2)Sc(CH2SiMe2CH2SiMe3)][MeB(C6F5)3][B(C6F5)4] (4) featuring a CH2SiMe2CH2SiMe3 ligand, formed as a result of methyl anion abstraction from silicon, with concomitant migration of the neighbouring CH2SiMe3 group from scandium to silicon. The MeB(C6F5)3 anion in 4 forms a contact ion pair. By contrast, reaction of 1 with [CPh3][B(C6F5)3] in C6D5Br/toluene or o-C6H4F2/toluene afforded dicationic [(XII2)Sc(CH2SiMe3)(ηx-toluene)n][B(C6F5)4]2 (5). Compounds 2-4 showed negligible ethylene polymerization activity, whereas 5 is highly active (up to 870 kg mol-1 h-1 atm-1 in o-C6H4F2/toluene under 1 atm of ethylene at room temperature).
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Affiliation(s)
- Aathith Vasanthakumar
- Department of Chemistry, McMaster University 1280 Main Street West Hamilton Ontario L8S 4M1 Canada
| | - Jeffrey S Price
- Department of Chemistry, McMaster University 1280 Main Street West Hamilton Ontario L8S 4M1 Canada
| | - David J H Emslie
- Department of Chemistry, McMaster University 1280 Main Street West Hamilton Ontario L8S 4M1 Canada
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McMullen JS, Huo R, Vasko P, Edwards AJ, Hicks J. Anionic Magnesium and Calcium Hydrides: Transforming CO into Unsaturated Disilyl Ethers. Angew Chem Int Ed Engl 2023; 62:e202215218. [PMID: 36344462 PMCID: PMC10100151 DOI: 10.1002/anie.202215218] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Indexed: 11/09/2022]
Abstract
The synthesis, characterisation and reactivity of two isostructural anionic magnesium and calcium complexes is reported. By X-ray and neutron diffraction techniques, the anionic hydrides are shown to exist as dimers, held together by a range of interactions between the two anions and two bridging potassium cations. Unlike the vast proportion of previously reported dimeric group 2 hydrides, which have hydrides that bridge two group 2 centres, here the hydrides are shown to be "terminal", but stabilised by interactions with the potassium cations. Both anionic hydrides were found to insert and couple CO under mild reaction conditions to give the corresponding group 2 cis-ethenediolate complexes. These cis-ethenediolate complexes were found to undergo salt elimination reactions with silyl chlorides, allowing access to small unsaturated disilyl ethers with a high percentage of their mass originating from the C1 source CO.
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Affiliation(s)
- Jacob S McMullen
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| | - Ryan Huo
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
| | - Petra Vasko
- Department of Chemistry, University of Helsinki, A.I. Virtasen aukio 1, P.O. Box 55, 00014, Helsinki, Finland
| | - Alison J Edwards
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, NSW 2234, Australia
| | - Jamie Hicks
- Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia
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Nelmes GR, Brothers PJ, Hicks J. Convenient one‐pot synthesis and coordination chemistry of a bulky asymmetrical 9,10‐dihydroacridine‐based ligand. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202200127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Gareth R. Nelmes
- Australian National University Research School of Chemistry Sullivans Creek Road 2601 Acton AUSTRALIA
| | - Penelope J. Brothers
- Australian National University Research School of Chemistry Sullivans Creek Road 2601 Acton AUSTRALIA
| | - Jamie Hicks
- Australian National University Research School of Chemistry Sullivans Creek Road 2601 Acton AUSTRALIA
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8
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Lim LF, Judd M, Vasko P, Gardiner MG, Pantazis DA, Cox N, Hicks J. Crystalline Germanium(I) and Tin(I) Centered Radical Anions. Angew Chem Int Ed Engl 2022; 61:e202201248. [PMID: 35266609 PMCID: PMC9401049 DOI: 10.1002/anie.202201248] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Indexed: 01/03/2023]
Affiliation(s)
- Li Feng Lim
- Research School of Chemistry Australian National University Acton ACT, 2601 Australia
| | - Martyna Judd
- Research School of Chemistry Australian National University Acton ACT, 2601 Australia
| | - Petra Vasko
- Department of Chemistry University of Helsinki P.O. Box 55 00014 Helsinki Finland
| | - Michael G. Gardiner
- Research School of Chemistry Australian National University Acton ACT, 2601 Australia
| | - Dimitrios A. Pantazis
- Max-Planck Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Nicholas Cox
- Research School of Chemistry Australian National University Acton ACT, 2601 Australia
| | - Jamie Hicks
- Research School of Chemistry Australian National University Acton ACT, 2601 Australia
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9
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Lim LF, Judd M, Vasko P, Gardiner MG, Pantazis DA, Cox N, Hicks J. Crystalline Germanium(I) and Tin(I) Centered Radical Anions. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202201248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Li Feng Lim
- Australian National University Research School of Chemistry Sullivans Creek Road 2601 Acton AUSTRALIA
| | - Martyna Judd
- Australian National University Research School of Chemistry Sullivans Creek Road 2601 Acton AUSTRALIA
| | - Petra Vasko
- University of Helsinki: Helsingin Yliopisto Department of Chemistry P.O. Box 55 FI-00014 Helsinki FINLAND
| | - Michael G. Gardiner
- Australian National University Research School of Chemistry Sullivans Creek Road 2601 Acton AUSTRALIA
| | - Dimitrios A. Pantazis
- Max-Planck-Institut fur Kohlenforschung Institut fur Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr GERMANY
| | - Nicholas Cox
- Australian National University Research School of Chemistry Sullivas Creek Road 2601 Acton AUSTRALIA
| | - Jamie Hicks
- Australian National University Research School of Chemistry Sullivans Creek Road 2601 Acton AUSTRALIA
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Mondal R, Yuvaraj K, Rajeshkumar T, Maron L, Jones C. Reductive activation of N 2 using a calcium/potassium bimetallic system supported by an extremely bulky diamide ligand. Chem Commun (Camb) 2022; 58:12665-12668. [DOI: 10.1039/d2cc04841h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Potassium reduction of a bulky diamido-calcium complex under an N2 atmosphere afforded the first well-defined, hetero-bimetallic s-block metal complex of activated dinitrogen.
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Affiliation(s)
- Rahul Mondal
- School of Chemistry, Monash University, PO Box 23, Melbourne, VIC, 3800, Australia
| | - K. Yuvaraj
- School of Chemistry, Monash University, PO Box 23, Melbourne, VIC, 3800, Australia
| | - Thayalan Rajeshkumar
- Université de Toulouse et CNRS, INSA, UPS, UMR5215, LPCNO, 135 Avenue de Rangueil, 31077 Toulouse, France
| | - Laurent Maron
- Université de Toulouse et CNRS, INSA, UPS, UMR5215, LPCNO, 135 Avenue de Rangueil, 31077 Toulouse, France
| | - Cameron Jones
- School of Chemistry, Monash University, PO Box 23, Melbourne, VIC, 3800, Australia
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