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1. Magnetic properties of transition metal dimers probed by inelastic neutron scattering

Author

Ansbro, Simon, Moreno-Pineda, Eufemio, Yu, Wen, Ollivier, Jacques, Mutka, Hannu, Ruben, Mario, and Chiesa, Alessandro

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

The physical characterisation and understanding of molecular magnetic materials is one of the most important steps towards the integration of such systems in hybrid spintronic devices. Amongst the many characterisation techniques employed in such a task, Inelastic Neutron Scattering (INS) stands as one of the most powerful and sensitive tools to investigate their spin dynamics. Herein, the magnetic properties and spin dynamics of two dinuclear complexes, namely [(M(hfacac)$_2$)$_2$(bpym)] (where M = Ni$^{2+}$, Co$^{2+}$, abbreviated in the following as Ni$_2$, Co$_2$) are reported. These are model systems that could constitute fundamental units of future spintronic devices. By exploiting the highly sensitive IN5 Cold INS spectrometer, we are able to gain a deep insight into the spin dynamics of Ni$_2$ and to fully obtain the microscopic spin Hamiltonian parameters; while for Co$_2$, a multitude of INS transitions are observed demonstrating the complexity of the magnetic properties of octahedral cobalt-based systems.

Published
2021
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2. Size-Controlled Hapticity Switching in [Ln(C9 H9 )(C8 H8 )] Sandwiches.

Author

Tricoire, Maxime, Münzfeld, Luca, Moutet, Jules, Mahieu, Nolwenn, La Droitte, Léo, Moreno-Pineda, Eufemio, Gendron, Frédéric, Hilgar, Jeremy, Rinehart, Jeffrey, Ruben, Mario, Le Guennic, Boris, Cador, Olivier, Roesky, Peter, and Nocton, Grégory

Subjects
cyclononatetraenyl, lanthanides, magnetism, organometallics, single molecule magnets
Abstract

Sandwich complexes of lanthanides have recently attracted a considerable amount of interest due to their applications as Single Molecule Magnet (SMM). Herein, a comprehensive series of heteroleptic lanthanide sandwich complexes ligated by the cyclononatetraenyl (Cnt) and the cyclooctatetraenyl (Cot) ligand [Ln(Cot)(Cnt)] (Ln=Tb, Dy, Er, Ho, Yb, and Lu) is reported. The coordination behavior of the Cnt ligand has been investigated along the series and shows different coordination patterns in the solid-state depending on the size of the corresponding lanthanide ion without altering its overall anisotropy. Besides the characterization in the solid state by single-crystal X-ray diffraction and in solution by 1 H NMR, static magnetic studies and ab initio computational studies were performed.

Published
2021

3. Observation of Cooperative Electronic Quantum Tunneling: Increasing Accessible Nuclear States in a Molecular Qudit

Author

Moreno-Pineda, Eufemio, Klyatskaya, Svetlana, Du, Ping, Damjanović, Marko, Taran, Gheorghe, Wernsdorfer, Wolfgang, and Ruben, Mario

Subjects
Quantum Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Chemical Physics
Abstract

As an extension of two-level quantum bits (qubits), multilevel systems, so-called qudits, where d represents the Hilbert space dimension, have been predicted to reduce the number of iterations in quantum computation algorithms. This has been tested in the well-known [TbPc2]0 SMM, which allowed the implementation of the Grover algorithm in a single molecular unit. In the quest for molecular systems possessing an increased number of accessible nuclear spin states, we explore herein a dimeric Tb2-SMM via single crystal {\mu}-SQUID measurements at sub-Kelvin temperatures. We observe ferromagnetic interactions between the Tb(III) ions and cooperative quantum tunneling of the electronic spins with spin ground state \textit{J} = {\pm}6. The strong hyperfine coupling with the Tb(III) nuclear spins leads to a multitude of spin reversal paths leading to seven strong hyperfine driven tunneling steps in the hysteresis loops. Our results show the possibility to read-out the Tb(III) nuclear spin states via the cooperative tunneling of the electronic spins, making the dimeric Tb2-SMM an excellent nuclear spin qudit candidate with d =16., Comment: Manuscript contains 17 pages, 4 figures, and SI contains 10 pages and 8 figures

Published
2020
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4. Cycloheptatrienyl-Bridged Triple-Decker Complexes

Author

Hauser, Adrian, primary, Münzfeld, Luca, additional, Schlittenhardt, Sören, additional, Uhlmann, Cedric, additional, Leyen, Louis, additional, Moreno-Pineda, Eufemio, additional, Ruben, Mario, additional, and Roesky, Peter W., additional

Published
2024
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5. Molecular Spin Qudits for Quantum Algorithms

Author

Moreno-Pineda, Eufemio, Godfrin, Clément, Balestro, Franck, Wernsdorfer, Wolfgang, and Ruben, Mario

Subjects
Quantum Physics
Abstract

Presently, one of the most ambitious technological goals is the development of devices working under the laws of quantum mechanics. One prominent target is the quantum computer, which would allow the processing of information at quantum level for purposes not achievable with even the most powerful computer resources. The large-scale implementation of quantum information would be a game changer for current technology, because it would allow unprecedented parallelised computation and secure encryption based on the principles of quantum superposition and entanglement. Currently, there are several physical platforms racing to achieve the level of performance required for the quantum hardware to step into the realm of practical quantum information applications. Several materials have been proposed to fulfil this task, ranging from quantum dots, Bose-Einstein condensates, spin impurities, superconducting circuits, molecules, amongst others. Magnetic molecules are among the list of promising building blocks, due to (i) their intrinsic monodispersity, (ii) discrete energy levels (iii) the possibility of chemical quantum state engineering, and (iv) their multilevel characteristics, leading to the so called Qudits (d > 2), amongst others. Herein we review how a molecular multilevel nuclear spin qubit (or qudit, where d = 4), known as TbPc2, gathers all the necessary requirements to perform as a molecular hardware platform with a first generation of molecular devices enabling even quantum algorithm operations., Comment: Chem. Soc. Rev., 2017, Advance Article

Published
2017
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6. Magnetic behaviour of a spin-canted asymmetric lanthanide quinolate trimer.

Author

Batista, Lester, Paul, Sagar, Molina-Jirón, Concepción, Jaén, Juan A., Fensker, Dieter, Fuhr, Olaf, Ruben, Mario, Wernsdorfer, Wolfgang, and Moreno-Pineda, Eufemio

Subjects
MAGNETIC susceptibility, CHEMICAL formulas, HYSTERESIS loop, DYSPROSIUM, ANISOTROPY, SUPERCONDUCTING quantum interference devices
Abstract

An asymmetrical dysprosium trimer with a molecular formula of [Dy3(hq)7(hqH)(NO3)2(H2O)] was obtained through a reflux reaction employing as starting material Dy(NO3)3·nH2O and 8-quinolinoline as ligand. Magnetic susceptibility investigations show the system to be an SMM, which was corroborated by sub-Kelvin μSQUID studies. Upon cooling, the magnetic susceptibility also exhibits a decrease in the χMT product, which was confirmed to be due to intramolecular antiferromagnetic interactions. μSQUID measurements, moreover, reveal a marked magnetic behaviour in the angular dependence of the hysteresis loops. The latter is a direct consequence of the non-colinear spin arrangement of the anisotropy axes of each Dy(III) ion in [Dy3(hq)7(hqH)(NO3)2(H2O)] and the interaction between the ions, as also evidenced by CASSCF calculations. Our results evidence the effect of spin canting along with the intramolecular interactions, which can induce non-trivial magnetic behaviour in SMMs. [ABSTRACT FROM AUTHOR]

Published
2024
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7. Cover Picture: Unique Double and Triple Decker Arrangements of Rare‐Earth 9,10‐Diborataanthracene Complexes Featuring Single‐Molecule Magnet Characteristics

Author

Uhlmann, Cedric, primary, Münzfeld, Luca, additional, Hauser, Adrian, additional, Ruan, Ting‐Ting, additional, Kuppusamy, Senthil Kumar, additional, Jin, Chengyu, additional, Ruben, Mario, additional, Fink, Karin, additional, Moreno‐Pineda, Eufemio, additional, and Roesky, Peter W., additional

Published
2024
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11. Unique Double and Triple Decker Arrangements of Rare‐Earth 9,10‐Diborataanthracene Complexes Featuring Single‐Molecule Magnet Characteristics.

Author

Uhlmann, Cedric, Münzfeld, Luca, Hauser, Adrian, Ruan, Ting‐Ting, Kumar Kuppusamy, Senthil, Jin, Chengyu, Ruben, Mario, Fink, Karin, Moreno‐Pineda, Eufemio, and Roesky, Peter W.

Subjects
SINGLE molecule magnets, COORDINATE covalent bond, SANDWICH construction (Materials), RARE earth metals, COORDINATION polymers, ELIMINATION reactions, RARE earth oxides
Abstract

Herein, we present the first report on the synthesis of rare‐earth complexes featuring a 9,10‐diborataanthracene ligand. This 14‐π‐electron ligand is highly reductive and was previously used in small‐molecule activation. Salt elimination reactions between dipotassium 9,10‐diethyl‐9,10‐diborataanthracene [K2(DEDBA)] and [LnIII(η8‐CotTIPS)(BH4)(thf)x] (CotTIPS=1,4‐(iPr3Si)2C8H6) in a 1 : 1 ratio yielded heteroleptic sandwich complexes [K(η8‐CotTIPS)LnIII(η6‐DEDBA)] (Ln=Y, Dy, Er). These compounds form Lewis‐base‐free one‐dimensional coordination polymers when crystallised from toluene. In contrast, reaction of [K2(DEDBA)] and [LnIII(η8‐CotTIPS)(BH4)(thf)x] in a 1 : 2 ratio led to the formation of heteroleptic triple‐decker complexes [(η8‐CotTIPS)LnIII(μ‐η6:η6‐DEDBA)LnIII(η8‐CotTIPS)] (Ln=Y, Dy, Er). Notably, these are not only the first lanthanide triple‐decker compounds featuring a six‐membered ring as a deck but also the first trivalent lanthanide triple‐decker featuring a heterocycle in the coordination sphere. Magnetic investigations reveal that [K(η8‐CotTIPS)LnIII(η6‐DEDBA)] (Ln=Dy, Er) and [(η8‐CotTIPS)ErIII(μ‐η6:η6‐DEDBA)ErIII(η8‐CotTIPS)] exhibit Single‐Molecule Magnet (SMM) behaviour. In the case of [(η8‐CotTIPS)LnIII(μ‐η6:η6‐DEDBA)LnIII(η8‐CotTIPS)] (Ln=Dy, Er), the introduction of a second near lanthanide ion results in strong antiferromagnetic interactions, allowing the enhancement of the magnetic characteristic of the system, compared to the quasi isolated counterpart. This research renews the overlooked coordination chemistry of the DBA ligand and expands it to encompass rare‐earth elements. [ABSTRACT FROM AUTHOR]

Published
2024
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13. New f-block and mixed d,f-block molecular nanomagnets

Author

Moreno Pineda, Eufemio and Mcinnes, Eric

Subjects
546, Molecular magnetism, EPR, SQUID, quantum computing, MCE, Single molecule magnets, lanthanides
Abstract

Molecular Nanomagnets have been proposed as plausible candidates in a variety of futuristic applications. Thorough understanding of the magnetic properties of these systems is therefore necessary to develop devices that include such units. The aim of this thesis is to synthesise and structurally and magnetically characterise a range of systems that could be used as elementary units in three proposed applications such as: data storage devices, magnetic refrigerants and qubits for quantum computing. A series of mixed 3d/4f metal complexes were synthesised through solvothermal reactions and characterised by X-ray single crystal diffraction and SQUID magnetometry. Through indirect methods it was possible to obtain high magnetic entropy change for some systems. It was also possible to obtain some insight into the magnetic interactions within the systems through modelling the magnetic data. The role of the 4f-4f and 3d-4f interactions in two sets of molecules is also described. The first study is in an asymmetric dysprosium dimer, where through a range of experimental techniques and advanced theoretical methods, such ab-initio calculations we are able to explain the role of the intramolecular interactions and their effect on the SMM properties of this system. Similarly, insight into the role of the 3d-4f interactions is achieved through the observation of the magnetic behaviour of a family of 27 tetranuclear systems, though SQUID data and ab-initio calculations. Finally, chemical functionalization of a well-proposed qubits, namely {Cr7Ni} and subsequent reaction with a redox active metal ion, CoII/III, two {Cr7Ni} systems are linked. The magnitude of the exchange interaction between the {Cr7Ni}-CoII-{Cr7Ni} was determined through Electron Paramagnetic Resonance. Furthermore, by chemical oxidation/reduction of the cobalt between paramagnetic and diamagneticstates, i.e. CoII and CoIII respectively, we demonstrate that the interaction can be switched ON/OFF. This characteristic makes of these systems candidates to function as a SWAP gate.

Published
2014

14. Insight into ferromagnetic interactions in CuII–LnIII dimers with a compartmental ligand.

Author

Panja, Anangamohan, Paul, Sagar, Moreno-Pineda, Eufemio, Herchel, Radovan, Jana, Narayan Ch., Brandão, Paula, Novitchi, Ghenadie, and Wernsdorfer, Wolfgang

Subjects
RARE earth metals, TERBIUM, DIMERS, FERROMAGNETIC materials, MAGNETIC measurements, MAGNETIC susceptibility, HYSTERESIS loop
Abstract

In the last two decades, efforts have been devoted to obtaining insight into the magnetic interactions between CuII and LnIII utilizing experimental and theoretical means. Experimentally, it has been observed that the exchange coupling (J) in CuII–LnIII systems is often found to be ferromagnetic for ≥4f7 metal ions. However, exchange interactions at sub-Kelvin temperatures between CuII and the anisotropic/isotropic LnIII ions are not often explored. In this report, we have synthesized a series of heterobimetallic [CuLn(HL)(μ-piv)(piv)2] complexes (LnIII = Gd (1), Tb (2), Dy (3) and Er (4)) from a new compartmental Schiff base ligand, N,N'-bis(3-methoxy-5-methylsalicylidene)-1,3-diamino-2-propanol (H3L). X-ray crystallographic analysis reveals that all four complexes are isostructural and isomorphous. Magnetic susceptibility measurements reveal a ferromagnetic coupling between the CuII ion and its respective LnIII ion for all the complexes, as often observed. Moreover, μ-SQUID studies, at sub-Kelvin temperatures, show S-shaped hysteresis loops indicating the presence of antiferromagnetic coupling in complexes 1–3. The antiferromagnetic interaction is explained by considering the shortest Cu⋯Cu distance in the crystal structure. The nearly closed loops for 1–3 highlight their fast relaxation characteristics, while the opened loops for 4 might arise from intermolecular ordering. CASSCF calculations allow the quantitative assessment of the interactions, which are further supported by BS-DFT calculations. [ABSTRACT FROM AUTHOR]

Published
2024
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20. Frontispiece: Molecular Lanthanide Switches for Magnetism and Photoluminescence

Author

Münzfeld, Luca, primary, Dahlen, Milena, additional, Hauser, Adrian, additional, Mahieu, Nolwenn, additional, Kuppusamy, Senthil Kumar, additional, Moutet, Jules, additional, Tricoire, Maxime, additional, Köppe, Ralf, additional, La Droitte, Léo, additional, Cador, Olivier, additional, Le Guennic, Boris, additional, Nocton, Grégory, additional, Moreno‐Pineda, Eufemio, additional, Ruben, Mario, additional, and Roesky, Peter W., additional

Published
2023
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21. Molecular Lanthanide Switches for Magnetism and Photoluminescence

Author

Münzfeld, Luca, primary, Dahlen, Milena, additional, Hauser, Adrian, additional, Mahieu, Nolwenn, additional, Kuppusamy, Senthil Kumar, additional, Moutet, Jules, additional, Tricoire, Maxime, additional, Köppe, Ralf, additional, La Droitte, Léo, additional, Cador, Olivier, additional, Le Guennic, Boris, additional, Nocton, Grégory, additional, Moreno‐Pineda, Eufemio, additional, Ruben, Mario, additional, and Roesky, Peter W., additional

Published
2023
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26. Contributors

Author

Athanasopoulou, Angeliki A., primary, Demin, Vyacheslav A., additional, Domracheva, Natalia, additional, Emelyanov, Andrey V., additional, Förster, Stephan, additional, Friedrich, Thomas, additional, Gamer, Christoph, additional, Granovsky, Alexander B., additional, Guénin, Erwann, additional, Harding, David J., additional, Kalinin, Yurii E., additional, Kramarenko, Elena Yu., additional, Lai, Chih-Huang, additional, Lenglet, Luc, additional, Moreno-Pineda, Eufemio, additional, Motte, Laurence, additional, Muscas, Giuseppe, additional, Nodaraki, Lydia E., additional, Peddis, Davide, additional, Pineider, Francesco, additional, Radu, Florin, additional, Rehberg, Ingo, additional, Rentschler, Eva, additional, Rosenfeldt, Sabine, additional, Rylkov, Vladimir V., additional, Sánchez-Barriga, Jaime, additional, Sangregorio, Claudio, additional, Shamonin, Mikhail, additional, Sitnikov, Alexander V., additional, Tagirov, Lenar R., additional, Terrasson, Vincent, additional, Tugushev, Victor V., additional, Tuna, Floriana, additional, Useinov, Artur, additional, Useinov, Niazbeсk Kh., additional, Völker, Lara, additional, Weber, Birgit, additional, and Yaacoub, Nader, additional

Published
2018
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30. Lanthanide Luminescence Thermometry and Slow Magnetic Relaxation in 3-D Polycyanidometallate-Based Materials

Author

Karachousos-Spiliotakopoulos, Konstantinos, primary, Tangoulis, Vassilis, additional, Panagiotou, Nikos, additional, Tasiopoulos, Anastasios, additional, Nastopoulos, Vassilis, additional, Moreno-Pineda, Eufemio, additional, Wernsdorfer, Wolfgang, additional, Schulze, Michael, additional, Botas, Alexandre M. P., additional, and Carlos, Luis D., additional

Published
2022
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31. Direct determination of high-order transverse ligand field parameters via µSQUID-EPR in a Et4N[160GdPc2] SMM.

Author

Taran, Gheorghe, Moreno-Pineda, Eufemio, Schulze, Michael, Bonet, Edgar, Ruben, Mario, and Wernsdorfer, Wolfgang

Subjects
LIGAND field theory, SUPERCONDUCTING quantum interference devices, SINGLE molecule magnets, ELECTRON paramagnetic resonance spectroscopy, QUANTUM information science, ACTIVATION energy
Abstract

The development of quantum technologies requires a thorough understanding of systems possessing quantum effects that can ultimately be manipulated. In the field of molecular magnetism, one of the main challenges is to measure high-order ligand field parameters, which play an essential role in the relaxation properties of SMMs. The development of highly advanced theoretical calculations has allowed the ab-initio determination of such parameters; however, currently, there is a lack of quantitative assessment of how good the ab-initio parameters are. In our quest for technologies that can allow the extraction of such elusive parameters, we develop an experimental technique that combines the EPR spectroscopy and µSQUID magnetometry. We demonstrate the power of the technique by performing EPR-µSQUID measurement of a magnetically diluted single crystal of Et4N[GdPc2], by sweeping the magnetic field and applying a range of multifrequency microwave pulses. As a result, we were able to directly determine the high-order ligand field parameters of the system, enabling us to test theoretical predictions made by state-of-the-art ab-initio methods. Single molecule magnets (SMMs) are molecules with magnetic states separated by an energy barrier. These two (or more) states can serve as basis for quantum information processing, but this requires a detailed understanding of the ligand field of the molecule that forms the SMM. Here, Taran et al use a combination of two experimental techniques, µSQUID and EPR, to precisely measure the higher-order ligand field parameters. [ABSTRACT FROM AUTHOR]

Published
2023
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34. High-Performance Luminescence Thermometer with Field-Induced Slow Magnetic Relaxation Based on a Heterometallic Cyanido-Bridged 3d–4f Complex

Author

Tangoulis, Vassilis, primary, Nastopoulos, Vassilis, additional, Panagiotou, Nikos, additional, Tasiopoulos, Anastasios, additional, Itskos, Grigorios, additional, Athanasiou, Modestos, additional, Moreno-Pineda, Eufemio, additional, Wernsdorfer, Wolfgang, additional, Schulze, Michael, additional, and Malina, Ondřej, additional

Published
2022
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35. Luminescence thermometry and field induced slow magnetic relaxation based on a near infrared emissive heterometallic complex

Author

Karachousos-Spiliotakopoulos, Konstantinos, primary, Tangoulis, Vassilis, additional, Panagiotou, Nikos, additional, Tasiopoulos, Anastasios, additional, Moreno-Pineda, Eufemio, additional, Wernsdorfer, Wolfgang, additional, Schulze, Michael, additional, Botas, Alexandre M. P., additional, and Carlos, Luis D., additional

Published
2022
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37. NiII36‐Containing 54‐Tungsto‐6‐Silicate: Synthesis, Structure, Magnetic and Electrochemical Studies

Author

Goura, Joydeb, primary, Bassil, Bassem S., additional, Ma, Xiang, additional, Rajan, Ananthu, additional, Moreno‐Pineda, Eufemio, additional, Schnack, Jürgen, additional, Ibrahim, Masooma, additional, Powell, Annie K., additional, Ruben, Mario, additional, Wang, Jingjing, additional, Ruhlmann, Laurent, additional, and Kortz, Ulrich, additional

Published
2021
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40. Cover Feature: Size‐Controlled Hapticity Switching in [Ln(C9H9)(C8H8)] Sandwiches (Chem. Eur. J. 54/2021)

Author

Tricoire, Maxime, primary, Münzfeld, Luca, additional, Moutet, Jules, additional, Mahieu, Nolwenn, additional, La Droitte, Léo, additional, Moreno‐Pineda, Eufemio, additional, Gendron, Frédéric, additional, Hilgar, Jeremy D., additional, Rinehart, Jeffrey D., additional, Ruben, Mario, additional, Le Guennic, Boris, additional, Cador, Olivier, additional, Roesky, Peter W., additional, and Nocton, Grégory, additional

Published
2021
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41. Size‐Controlled Hapticity Switching in [Ln(C9H9)(C8H8)] Sandwiches

Author

Tricoire, Maxime, primary, Münzfeld, Luca, additional, Moutet, Jules, additional, Mahieu, Nolwenn, additional, La Droitte, Léo, additional, Moreno‐Pineda, Eufemio, additional, Gendron, Frédéric, additional, Hilgar, Jeremy D., additional, Rinehart, Jeffrey D., additional, Ruben, Mario, additional, Le Guennic, Boris, additional, Cador, Olivier, additional, Roesky, Peter W., additional, and Nocton, Grégory, additional

Published
2021
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42. Chiral Resolution of Spin‐Crossover Active Iron(II) [2x2] Grid Complexes

Author

Suryadevara, Nithin, primary, Pausch, Ansgar, additional, Moreno‐Pineda, Eufemio, additional, Mizuno, Asato, additional, Bürck, Jochen, additional, Baksi, Ananya, additional, Hochdörffer, Tim, additional, Šalitroš, Ivan, additional, Ulrich, Anne S., additional, Kappes, Manfred M., additional, Schünemann, Volker, additional, Klopper, Wim, additional, and Ruben, Mario, additional

Published
2021
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43. CO2Fixation by Dimeric Tb(III) Complexes: Synthesis, Structure, and Magnetism

Author

Dolai, Malay, Biswas, Surajit, Moreno-Pineda, Eufemio, Wernsdorfer, Wolfgang, Ali, Mahammad, Alshgari, Razan A., Wabaidur, Saikh Md., and Ghosh, Ashutosh

Abstract

Two dinuclear complexes, [Tb2(L1)2(piv)2(NO3)2]·H2O (1) and [Tb2(L2)2(CF3CO2)2(H2O)4].2NO3(2), have been prepared and characterized by single-crystal X-ray diffraction, where each metal ion is doubly phenoxido-bridged by the two phenolato oxygen atoms of the tetradentate Schiff-base ligand. Previous magnetic studies of 1show that it is not a single-molecule magnet (SMM), while AC magnetic measurements of 2show that it relaxes quite fast with μSQUID measurements revealing the presence of an interaction operating between the Tb ions. Through DC, μSQUID, and CASSCF calculations, the strength of the interaction in 2can be quantified, which is of dipolar origin. Both complexes showed efficient catalytic activity toward the carbon dioxide insertion reaction into epoxides for the formation of organic cyclic carbonates. Catalytic synthesis of organic cyclic carbonates smoothly occurred at 60 °C under1 bar carbon dioxide pressure and neat conditions. Exocyclic as well as endocyclic epoxides produced a respective cyclic carbonate product with moderate to high yield (43–100%). Moreover, a high turnover number (7300–10000) along with a high turnover frequency (537.5–5000 h–1) are found in this catalytic reaction.

Published
2023
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44. Heteroleptic, polynuclear dysprosium($_{III}$)-carbamato complexes throughin situcarbon dioxide capture

Author

Schlittenhardt, Sören, Moreno-Pineda, Eufemio, and Ruben, Mario

Subjects
Technology, ddc:600
Abstract

Amine groups are among the most effective systems for carbon dioxide capture. Reminiscent of the activation of nature's most abundant enzyme RuBisCO, the treatment of amines with CO$_{2}$ in the presence of oxophilic metal ions, e.g. Mg$^{2+}$, results in the formation of carbamates. Here we report the synthesis, structure and magnetic properties of three new dysprosium-carbamato complexes. The reaction of gaseous CO$_{2}$ with N,N-diisopropylamine and DyCl$_{3}$(DME)$_{2}$ (DME = Dimethoxyethane) in toluene leads to the formation of the tetrametallic complex [Dy$_{4}$(O$_{2}$CNiPr$_{2}$)$_{10}$(O-C$_{2}$H$_{4}$–OMe)$_{2}$]. The addition of 2-hydroxy-3-methoxybenzaldehyde-N-methylimine yields the hexametallic compound [Dy$_{6}$(O$_{2}$CNiPr$_{2}$)$_{8}$(O-C$_{2}$H$_{4}$–OMe)$_{2}$(CO$_{3}$)$_{2}$(C$_{9}$O$_{2}$NH$_{10}$)$_{4}$] in which the metal sites form a chair-like configuration; The same hexanuclear motif is obtained using N,N-dibenzylamine. We show that by employing CO$_{2}$ as a feedstock, we are able to capture up to 2.5 molecules of CO$_{2}$ per Dy ion. Magnetic measurements show a decreasing χMT at low temperatures. Combining the experimental magnetic data with ab initio calculations reveils tilting of the easy axes and implies the presence of antiferromagnetic interactions between the Dy($_{III}$) metal ions.

Published
2021
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46. Gd-3 Triangles in a Polyoxometalate Matrix: Tuning Molecular Magnetocaloric Effects in {Gd30M8} Polyoxometalate/Cluster Hybrids Through Variation of M2+

Author

Ibrahim, Masooma, Peng, Yan, Moreno-Pineda, Eufemio, Anson, Christopher E., Schnack, Jürgen, and Powell, Annie K.

Subjects
heterometallics, (3d/4f), magnetism, magnetocaloric effects, lanthanides, polyoxometalates, molecular
Abstract

The syntheses and structures of a family of five new Ln/3d cluster containing polyoxometalates (POMs) [{(GeW9O34)(2)Ln(3)(III)(CO3)(OH2)(3)}(6){3M(2)(II)Ln(3)(III)(mu(3)-OH)(6) (OH2)(6)}(4)](50-) {Ln(30)M(8)}, where Ln = Gd or Y, and M = Zn, Mn, Co, are presented. This structural motif of a giant tetrahedron contains {Ln(3)(III)} and {M(2)(II)Ln(3)(III)}cluster units which are well-isolated within the diamagnetic polyoxotungstate system. The magnetic properties of {Gd30Mn8}, {Y30Mn8} and {Gd30Zn8} can be successfully modeled using a Heisenberg approach. Investigation of their magnetocaloric effect (MCE) reveals that this can be tuned through variation of the 3d metal ion. This is the first such systematic study on heterometallic 3d-4f- POM clusters. The {Gd30Zn8} analogue illustrates a promising way forward to magnetic cooling at sub-Kelvin temperatures.

Published
2021

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