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Coles SJ, McCormick McPherson LJ, Platt AWG, Singh K. Solid State and Solution Structures of Lanthanide Nitrate Complexes of Tris-(1-napthylphosphine oxide). Molecules 2024; 29:2580. [PMID: 38893455 PMCID: PMC11173986 DOI: 10.3390/molecules29112580] [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: 05/02/2024] [Revised: 05/16/2024] [Accepted: 05/24/2024] [Indexed: 06/21/2024] Open
Abstract
Coordination complexes of lanthanide metals with tris-1-naphthylphosphine oxide (Nap3PO, L) have not been previously reported in the literature. We describe here the formation of lanthanide(III) nitrate complexes Ln(NO3)3L4 (Ln = Eu to Lu) and the structures of [Ln(NO3)3L2]·2L (Ln = Eu, Dy, Ho, Er) and L. The core structure of the complexes is an eight-coordinate [Ln(NO3)3L2] with the third and fourth ligands H-bonded via their oxygen atoms to one of the naphthyl rings. The structures are compared with those of the analogous complexes of triphenylphosphine oxide and show that the Ln-O(P) bond in the Nap3PO complexes is slightly longer than expected on the basis of differences in coordination numbers. The reaction solutions, investigated by 31P and 13C NMR spectroscopy in CD3CN, show that coordination of L occurs across the lanthanide series, even though complexes can only be isolated from Eu onwards. Analysis of the 31P NMR paramagnetic shifts shows that there is a break in the solution structures with a difference between the lighter lanthanides (La-Eu) and heavier metals (Tb-Lu) which implies a minor difference in structures. The isolated complexes are very poorly soluble, but in CDCl3, NMR measurements show dissociation into [Ln(NO3)3L2] and 2L occurs.
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Affiliation(s)
- Simon J. Coles
- UK National Crystallography Service, Chemistry, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK; (S.J.C.); (L.J.M.M.)
| | - Laura J. McCormick McPherson
- UK National Crystallography Service, Chemistry, University of Southampton, Highfield Campus, Southampton SO17 1BJ, UK; (S.J.C.); (L.J.M.M.)
| | - Andrew W. G. Platt
- School of Health, Education, Policing and Sciences, Staffordshire University, Science Centre, Stoke-on-Trent ST4 2DF, UK
| | - Kuldip Singh
- Chemistry Department, The University of Leicester, Leicester LE1 7RH, UK;
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2
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Borah A, Dey S, Siddiqui K, Gupta SK, Rajaraman G, Murugavel R. Magnetic anisotropy in octahedral Dy(III) and Yb(III) complexes. Dalton Trans 2024; 53:7263-7267. [PMID: 38618749 DOI: 10.1039/d3dt04352e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
New organophosphate complexes [Ln(dippH)3(dippH2)3]·(H2O)6, (Ln = Dy, Yb and Y; dippH2 = 2,6-diisopropylphenyl phosphate), displaying octahedral coordination geometry around the metal ion, exhibit unusual slow relaxation of magnetisation, which is investigated through experimental studies and ab initio CASSCF calculations.
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Affiliation(s)
- Aditya Borah
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra, 400076, India.
- Department of Chemistry, Jengraimukh College, Majuli, Assam, 785105, India
| | - Sourav Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra, 400076, India.
| | - Kehkasha Siddiqui
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra, 400076, India.
| | - Sandeep K Gupta
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, Delhi, 110016, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra, 400076, India.
| | - Ramaswamy Murugavel
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra, 400076, India.
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3
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Gavrikov AV, Ilyukhin AB, Taydakov IV, Metlin MT, Datskevich NP, Buzoverov ME, Babeshkin KA, Efimov NN. Novel stable ytterbium acetylacetonate-quinaldinate complexes as single-molecule magnets and surprisingly efficient luminophores. Dalton Trans 2023; 52:17911-17927. [PMID: 37982138 DOI: 10.1039/d3dt03253a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
The first Yb complexes comprising a quinoline-2-carboxylate (quinaldinate, Q-) ligand, namely 1D-polymeric [Yb(acac)2(Q)]n (1, acac- is the acetylacetonate (pentane-2,4-dionate) anion) and mononuclear [Yb(acac)2(Q)(Phen)] (2, Phen is 1,10-phenanthroline), are reported. The bifunctionality of both complexes as field-induced single-molecule magnets (SMMs) and near IR luminophores has been revealed. The SMM properties of 1 and 2 have been discussed in terms of the geometry and composition of the coordination environment. Also, 1 is the first example of 1D-polymeric SMMs with the capped octahedral surrounding of Yb3+. The photoluminescence quantum yields (PLQYs) of 1 and 2 are 2 and 4%, respectively. The origins of this difference are discussed. Surprisingly, the PLQY value of 2 is high for compounds comprising a lot of C-H vibrational quenchers, being the highest one for reliably characterized Yb β-diketonate complexes, and surpassing those for complexes with a broad range of anionic ligands. In this respect, the role of the Phen ligand is to tune the coordination mode of Q- thereby decreasing the energy of coordinating C-O oscillators rather than to act as a typical antenna ligand. These results can give rise to an alternative route to elaborate efficient Yb-based luminophores via the substitution of the β-diketonate ligands controlled by the introduction of appropriate neutral ligands.
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Affiliation(s)
- Andrey V Gavrikov
- N.S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky prosp. 31, 119991 Moscow, Russian Federation.
| | - Andrey B Ilyukhin
- N.S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky prosp. 31, 119991 Moscow, Russian Federation.
| | - Ilya V Taydakov
- P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 53 Leninsky Prospect, 119991, Moscow, Russian Federation
| | - Mikhail T Metlin
- P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 53 Leninsky Prospect, 119991, Moscow, Russian Federation
- N.E. Bauman Moscow State Technical University, 2-ya Baumanskaya str. 5/1, 105005, Moscow, Russia
| | - Nikolay P Datskevich
- P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 53 Leninsky Prospect, 119991, Moscow, Russian Federation
| | - Mikhail E Buzoverov
- N.S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky prosp. 31, 119991 Moscow, Russian Federation.
| | - Konstantin A Babeshkin
- N.S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky prosp. 31, 119991 Moscow, Russian Federation.
| | - Nikolay N Efimov
- N.S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky prosp. 31, 119991 Moscow, Russian Federation.
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Tarannum I, Moorthy S, Singh SK. Understanding electrostatics and covalency effects in highly anisotropic organometallic sandwich dysprosium complexes [Dy(C mR m) 2] (where R = H, SiH 3, CH 3 and m = 4 to 9): a computational perspective. Dalton Trans 2023; 52:15576-15589. [PMID: 37786345 DOI: 10.1039/d3dt01646c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
In this article, we have thoroughly studied the electronic structure and 4f-ligand covalency of six mononuclear dysprosium organometallic sandwich complexes [Dy(CmRm)2]n+/- (where R = H, SiH3, CH3; m = 4 to 9; n = 1, 3) using both the scalar relativistic density functional and complete active space self-consistent field (CASSCF) and N-electron valence perturbation theory (NEVPT2) method to shed light on the ligand field effects in fine-tuning the magnetic anisotropy of these complexes. Energy decomposition analysis (EDA) and ab initio-based ligand field theory AILFT calculations predict the sizable 4f-ligand covalency in all these complexes. The analysis of CASSCF/NEVPT2 computed spin-Hamiltonian (SH) parameters indicates the stabilization of mJ |±15/2〉 for [Dy(C4(SiH3)4)2]- (1), [Dy(C5(CH3)5)2]+ (2) and [Dy(C6H6)2]3+ (3) complexes with the Ucal value of 1867.5, 1621.5 and 1070.8 cm-1, respectively. On the other hand, we observed mJ |±9/2〉 as the ground state for [Dy(C7H7)2]3- (4) and [Dy(C8H8)2]- (5) complexes with significantly smaller Ucal values of 237.1 and 38.6 cm-1 respectively. For the nine-membered ring [Dy(C9H9)2]+ (6) complex, we observed the stabilization of the mJ |±1/2〉 ground state, with the first excited state being located ∼29 cm-1 higher in energy. AILFT-NEVPT2 ligand field splitting analysis indicates that the presence of π-type 4f-ligand interactions in complexes 1-3 help generate the axial-ligand field, while the δ-type interactions in complexes 4-5 generate the equatorial ligand field despite the ligands approaching from the axial direction. As the ring size increases, φ-type interactions dominate, generating a pure equatorial ligand field stabilising mJ |±1/2〉 as the ground state for 6. Calculations suggest that the nature of the ligand field mainly governs the Ucal values in the following order: 4f-Lσ > 4f-Lπ > 4f-Lδ > 4f-Lφ. Calculations were performed by replacing ligands with CHELPG charges to access the crystal field (CF) effects which suggests the stabilization of pure mJ |±15/2〉 in all the charge-embedded models (1Q-6Q). Our findings point out that the crystal field and ligand field effects complement each other and generate a giant barrier for magnetic relaxation in the small ring complexes 1-3, while a relatively weak crystal field and adverse 4f-Lδ/4f-Lφ interactions diminish the SMM behaviour in the large ring complexes 4-6.
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Affiliation(s)
- Ibtesham Tarannum
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India.
| | - Shruti Moorthy
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India.
| | - Saurabh Kumar Singh
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India.
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Gupta SK, Dey S, Rajeshkumar T, Rajaraman G, Murugavel R. Deciphering the Role of Anions and Secondary Coordination Sphere in Tuning Anisotropy in Dy(III) Air-Stable D 5h SIMs*. Chemistry 2021; 28:e202103585. [PMID: 34788493 DOI: 10.1002/chem.202103585] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Indexed: 01/05/2023]
Abstract
Precise control of the crystal field and symmetry around the paramagnetic spin centre has recently facilitated the engineering of high-temperature single-ion magnets (SIMs), the smallest possible units for future spin-based devices. In the present work, we report a series of air-stable seven coordinate Dy(III) SIMs {[L2 Dy(H2 O)5 ][X]3 ⋅L2 ⋅n(H2 O), n = 0, X = Cl (1), n=1, X = Br (2), I (3)} possessing pseudo-D5h symmetry or pentagonal bipyramidal coordination geometry with high anisotropy energy barrier (Ueff ) and blocking temperature (TB ). While the strong axial coordination from the sterically encumbered phosphonamide, t BuPO(NHi Pr)2 (L), increases the overall anisotropy of the system, the presence of high symmetry significantly quenches quantum tunnelling of magnetization, which is the prominent deactivating factor encountered in SIMs. The energy barrier (Ueff ) and the blocking temperature (TB ) decrease in the order 3>2>1 with the change of anions from larger iodide to smaller strongly hydrogen-bonded chloride in the secondary coordination sphere, albeit the local coordination geometry and the symmetry around the Dy(III) display only slight deviations. Ab initio CASSCF/RASSI-SO/SINGLE_ANISO calculations provide deeper insights into the dynamics of magnetic relaxation in addition to the role of the secondary coordination sphere in modulating the anisotropy of the D5h systems, using diverse models. Thus, in addition to the importance of the crystal field and the symmetry to obtain high-temperature SIMs, this study also probes the significance of the secondary coordination sphere that can be tailored to accomplish novel SIMs.
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Affiliation(s)
- Sandeep K Gupta
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai, 400 076, India
| | - Sourav Dey
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai, 400 076, India
| | - Thayalan Rajeshkumar
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai, 400 076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai, 400 076, India
| | - Ramaswamy Murugavel
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai, 400 076, India
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Mondal A, Konar S. A remarkable energy barrier for spin reversal in a field induced dinuclear ytterbium single molecule magnet. Dalton Trans 2021; 50:13666-13670. [PMID: 34586116 DOI: 10.1039/d1dt02130c] [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
A dinuclear ytterbium complex has been designed with a strong ligand field in equatorial positions. Magnetic studies reveal the presence of easy-axis anisotropy and field induced slow relaxation of magnetization with a remarkable energy barrier, Ueff = 53.58 cm-1, the highest value reported for any Yb-based SMMs to date. Furthermore, the ab initio calculations disclose the importance of a weak axial ligand field to design high-performance Yb-based SMMs.
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Affiliation(s)
- Arpan Mondal
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal (IISERB), Bhopal By-pass Road, Bhauri, Bhopal-462066, India.
| | - Sanjit Konar
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal (IISERB), Bhopal By-pass Road, Bhauri, Bhopal-462066, India.
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Mondal A, Konar S. Strong Equatorial Crystal Field Enhances the Axial Anisotropy and Energy Barrier for Spin Reversal Process in Yb 2 Single Molecule Magnets. Chemistry 2021; 27:3449-3456. [PMID: 33084133 DOI: 10.1002/chem.202004379] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/20/2020] [Indexed: 02/03/2023]
Abstract
The importance of equatorial crystal fields on magnetic anisotropy of ytterbium single molecule magnets (SMMs) is observed for the first time. Herein, we report three similar dinuclear ytterbium complexes with the formula [Yb2 (3-OMe-L)2 (DMF)2 (NO3 )2 ]⋅DMF (1), [Yb2 (3-H-L)2 (DMF)2 (NO3 )2 ]⋅DMF⋅H2 O (2), and [Yb2 (3-NO3 -L)2 (DMF)2 (NO3 )2 ] (3), [where 3-X-H2 L=N'-(2-hydroxy-3-X-benzylidene)picolinohydrazide, X=OMe (1), H (2) NO2 (3)]. Detailed magnetic measurements reveal the presence of weak antiferromagnetic interactions between the Yb centers and a field-induced slow relaxation of magnetization in all complexes. A higher energy barrier for spin reversal was observed for complex 1 (Ueff =50 K) and it decreases in the order of 2 (47 K) to 3 (40 K). Notably, complex 1 shows a remarkable energy barrier within the frequency range of 1-850 Hz reported for Yb-based SMMs. Further, ab initio calculations show a higher axial anisotropy and lower quantum tunneling of magnetization (QTM) in the ground state for 1 compared to 2 and 3. It was also observed that the presence of a strong crystal field in the equatorial plane (when the ∡ O1-Yb-O3 bond angle is close to 90°) enhances the axial anisotropy and improves the SMM behavior in the studied complexes. Both the experimental and theoretical analysis of relaxation dynamics discloses that Raman and QTM play major role on slow relaxation process for all complexes. To provide more insight into the exchange interactions, broken-symmetry DFT calculations were performed.
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Affiliation(s)
- Arpan Mondal
- Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal By-pass Road, Bhauri, Bhopal, 462066, Madhya Pradesh, India
| | - Sanjit Konar
- Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhopal By-pass Road, Bhauri, Bhopal, 462066, Madhya Pradesh, India
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