1
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Chang X, Arnold ME, Blinder R, Zolg J, Wischnat J, van Slageren J, Jelezko F, Kuehne AJC, von Delius M. A Stable Chichibabin Diradicaloid with Near-Infrared Emission. Angew Chem Int Ed Engl 2024; 63:e202404853. [PMID: 38695271 DOI: 10.1002/anie.202404853] [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: 03/11/2024] [Indexed: 06/21/2024]
Abstract
Conjugated molecules with multiple radical centers such as the iconic Chichibabin diradicaloid hold promise as building blocks in materials for quantum sensing and quantum information processing. However, it is a considerable challenge to design simple analogues of the Chichibabin hydrocarbon that are chemically inert, exhibit high diradical character and emit light at a distinct wavelength that may offer an optical readout of the spin state in functional ensembles. Here we describe the serendipitous discovery of the stable TTM-TTM diradicaloid, which exhibits high diradical character, a striking sky-blue color and near-infrared (NIR) emission (in solution). This combination of properties is unique among related diradicaloids and is due to the presence of hydrogen and chlorine atoms in "just the right positions", allowing a perfectly planar, yet predominantly benzenoid bridge to connect the two sterically stabilized radical centers. In-depth studies of the optical and magnetic properties suggest that this structural motif could become a mainstay building block of organic spin materials.
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Affiliation(s)
- Xingmao Chang
- Institute of Organic Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Mona E Arnold
- Institute of Macromolecular and Organic Chemistry and Center for Integrated Quantum Science and Technology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Rémi Blinder
- Institute of Quantum Optics and Center for Integrated Quantum Science and Technology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Julia Zolg
- Institute of Macromolecular and Organic Chemistry and Center for Integrated Quantum Science and Technology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Jonathan Wischnat
- Institut für Physikalische Chemie and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Joris van Slageren
- Institut für Physikalische Chemie and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Fedor Jelezko
- Institute of Quantum Optics and Center for Integrated Quantum Science and Technology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Alexander J C Kuehne
- Institute of Macromolecular and Organic Chemistry and Center for Integrated Quantum Science and Technology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Max von Delius
- Institute of Organic Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
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2
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Santanni F, Little E, Lockyer SJ, Whitehead GFS, McInnes EJL, Timco GA, Bowen AM, Sessoli R, Winpenny REP. Weak Exchange Interactions in Multispin Systems: EPR Studies of Metalloporphyrins Decorated with {Cr 7Ni} Rings. Inorg Chem 2024. [PMID: 38941532 DOI: 10.1021/acs.inorgchem.4c01248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2024]
Abstract
Both metalloporphyrins and heterometallic {Cr7Ni} rings are of significant research interest due to their proposed roles in quantum information processing devices. In this study, we present a series of complexes in which [Cr7NiF3(Etglu)(O2CtBu)15] (N-EtgluH5 = N-ethyl-d-glucamine) heterometallic rings are coordinated to metalloporphyrin linkers: the symmetric [M(TPyP)] for M = Cu2+, VO2+, and H2TPyP = 5,10,15,20-tetra(4-pyridyl)porphyrin; and the asymmetric [{VO}(TrPPyP)] for H2(TrPPyP) = 5,10,15-(triphenyl)-20-(4-pyridyl)porphyrin. The magnetic interactions present in these complexes are unraveled using the continuous wave (CW) electron paramagnetic resonance (EPR) technique. The nature of the coupling between the {Cr7Ni} rings and the central metalloporphyrin is assessed by numerical simulations of CW EPR spectra and determined to be on the order of 0.01 cm-1, larger than the dipolar ones and suitable for individual spin addressability in multiqubit architectures.
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Affiliation(s)
- Fabio Santanni
- Dipartimento di Chimica "Ugo Schiff" & INSTM Unit, Università̀ degli Studi di Firenze, Via della Lastruccia 3, I50019 Sesto Fiorentino (Firenze), Italy
| | - Edmund Little
- Photon Science Institute and Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Selena J Lockyer
- Photon Science Institute and Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - George F S Whitehead
- Photon Science Institute and Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Eric J L McInnes
- Photon Science Institute and Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Grigore A Timco
- Photon Science Institute and Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Alice M Bowen
- Photon Science Institute and Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Roberta Sessoli
- Dipartimento di Chimica "Ugo Schiff" & INSTM Unit, Università̀ degli Studi di Firenze, Via della Lastruccia 3, I50019 Sesto Fiorentino (Firenze), Italy
| | - Richard E P Winpenny
- Photon Science Institute and Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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3
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Nodaraki L, Ariciu AM, Huh DN, Liu J, Martins DOTA, Ortu F, Winpenny REP, Chilton NF, McInnes EJL, Mills DP, Evans WJ, Tuna F. Ligand Effects on the Spin Relaxation Dynamics and Coherent Manipulation of Organometallic La(II) Potential Qu dits. J Am Chem Soc 2024; 146:15000-15009. [PMID: 38787801 PMCID: PMC11157535 DOI: 10.1021/jacs.3c12827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 05/12/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024]
Abstract
We present pulsed electron paramagnetic resonance (EPR) studies on three La(II) complexes, [K(2.2.2-cryptand)][La(Cp')3] (1), [K(2.2.2-cryptand)][La(Cp″)3] (2), and [K(2.2.2-cryptand)][La(Cptt)3] (3), which feature cyclopentadienyl derivatives as ligands [Cp' = C5H4SiMe3; Cp″ = C5H3(SiMe3)2; Cptt = C5H3(CMe3)2] and display a C3 symmetry. Long spin-lattice relaxation (T1) and phase memory (Tm) times are observed for all three compounds, but with significant variation in T1 among 1-3, with 3 being the slowest relaxing due to higher s-character of the SOMO. The dephasing times can be extended by more than an order of magnitude via dynamical decoupling experiments using a Carr-Purcell-Meiboom-Gill (CPMG) sequence, reaching 161 μs (5 K) for 3. Coherent spin manipulation is performed by the observation of Rabi quantum oscillations up to 80 K in this nuclear spin-rich environment (1H, 13C, and 29Si). The high nuclear spin of 139La (I = 7/2), and the ability to coherently manipulate all eight hyperfine transitions, makes these molecules promising candidates for application as qudits (multilevel quantum systems featuring d quantum states; d >2) for performing quantum operations within a single molecule. Application of HYSCORE techniques allows us to quantify the electron spin density at ligand nuclei and interrogate the role of functional groups to the electron spin relaxation properties.
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Affiliation(s)
- Lydia
E. Nodaraki
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
- Photon
Science Institute, University of Manchester, Manchester M13 9PL, U.K.
| | - Ana-Maria Ariciu
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
- Photon
Science Institute, University of Manchester, Manchester M13 9PL, U.K.
| | - Daniel N. Huh
- Department
of Chemistry, University of California, Irvine, California 92697, United States
of America
- Department
of Chemistry, University of Rhode Island, Kingston, Rhode Island 02881, United States
of America
| | - Jingjing Liu
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
| | - Daniel O. T. A. Martins
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
- Photon
Science Institute, University of Manchester, Manchester M13 9PL, U.K.
| | - Fabrizio Ortu
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
- School
of Chemistry, University of Leicester, Leicester LE1 7RH, U.K.
| | | | - Nicholas F. Chilton
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
- Research
School of Chemistry, Australian National
University, Canberra 2617, Australia
| | - Eric J. L. McInnes
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
- Photon
Science Institute, University of Manchester, Manchester M13 9PL, U.K.
| | - David P. Mills
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
| | - William J. Evans
- Department
of Chemistry, University of California, Irvine, California 92697, United States
of America
| | - Floriana Tuna
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
- Photon
Science Institute, University of Manchester, Manchester M13 9PL, U.K.
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4
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Murto P, Li B, Fu Y, Walker LE, Brown L, Bond AD, Zeng W, Chowdhury R, Cho HH, Yu CP, Grey CP, Friend RH, Bronstein H. Steric Control of Luminescence in Phenyl-Substituted Trityl Radicals. J Am Chem Soc 2024; 146:13133-13141. [PMID: 38695282 PMCID: PMC11099960 DOI: 10.1021/jacs.4c00292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 04/17/2024] [Accepted: 04/18/2024] [Indexed: 05/16/2024]
Abstract
Triphenylmethyl (trityl) radicals have shown potential for use in organic optoelectronic applications, but the design of practical trityl structures has been limited to donor/radical charge-transfer systems due to the poor luminescence of alternant symmetry hydrocarbons. Here, we circumvent the symmetry-forbidden transition of alternant hydrocarbons via excited-state symmetry breaking in a series of phenyl-substituted tris(2,4,6-trichlorophenyl)methyl (TTM) radicals. We show that 3-fold phenyl substitution enhances the emission of the TTM radical and that steric control modulates the optical properties in these systems. Simple ortho-methylphenyl substitution boosts the photoluminescence quantum efficiency from 1% (for TTM) to 65% at a peak wavelength of 612 nm (for 2-T3TTM) in solution. In the crystalline solid state, the neat 2-T3TTM radical shows a remarkably high photoluminescence quantum efficiency of 25% for emission peaking at 706 nm. This has implications in the design of aryl-substituted radical structures where the electronic coupling of the substituents influences variables such as emission, charge transfer, and spin interaction.
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Affiliation(s)
- Petri Murto
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Cambridge CB2 1EW, U.K.
- Cavendish
Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
| | - Biwen Li
- Cavendish
Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
| | - Yao Fu
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Cambridge CB2 1EW, U.K.
| | - Lucy E. Walker
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Cambridge CB2 1EW, U.K.
- Cavendish
Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
| | - Laura Brown
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Cambridge CB2 1EW, U.K.
| | - Andrew D. Bond
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Cambridge CB2 1EW, U.K.
| | - Weixuan Zeng
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Cambridge CB2 1EW, U.K.
| | | | - Hwan-Hee Cho
- Cavendish
Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
| | - Craig P. Yu
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Cambridge CB2 1EW, U.K.
- Cavendish
Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
| | - Clare P. Grey
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Cambridge CB2 1EW, U.K.
| | - Richard H. Friend
- Cavendish
Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
| | - Hugo Bronstein
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Cambridge CB2 1EW, U.K.
- Cavendish
Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K.
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5
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Gabarró-Riera G, Sañudo EC. Challenges for exploiting nanomagnet properties on surfaces. Commun Chem 2024; 7:99. [PMID: 38693350 PMCID: PMC11063158 DOI: 10.1038/s42004-024-01183-6] [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: 11/28/2023] [Accepted: 04/17/2024] [Indexed: 05/03/2024] Open
Abstract
Molecular complexes with single-molecule magnet (SMM) or qubit properties, commonly called molecular nanomagnets, are great candidates for information storage or quantum information processing technologies. However, the implementation of molecular nanomagnets in devices for the above-mentioned applications requires controlled surface deposition and addressing the nanomagnets' properties on the surface. This Perspectives paper gives a brief overview of molecular properties on a surface relevant for magnetic molecules and how they are affected when the molecules interact with a surface; then, we focus on systems of increasing complexity, where the relevant SMMs and qubit properties have been observed for the molecules deposited on surfaces; finally, future perspectives, including possible ways of overcoming the problems encountered so far are discussed.
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Affiliation(s)
- Guillem Gabarró-Riera
- Institut de Nanociència i Nanotecnologia, Universitat de Barcelona IN2UB, C/Martí i Franqués 1-11, 08028, Barcelona, Spain
- Departament de Química Inorgànica i Orgànica, Universitat de Barcelona, C/Martí i Franqués 1-11, 08028, Barcelona, Spain
| | - E Carolina Sañudo
- Institut de Nanociència i Nanotecnologia, Universitat de Barcelona IN2UB, C/Martí i Franqués 1-11, 08028, Barcelona, Spain.
- Departament de Química Inorgànica i Orgànica, Universitat de Barcelona, C/Martí i Franqués 1-11, 08028, Barcelona, Spain.
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6
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Kopp K, Westhofen L, Hett T, Felix Schwering-Sohnrey M, Mayländer M, Richert S, Schiemann O. Synthesis and dark state EPR properties of PDI-trityl dyads and triads. Chemistry 2024; 30:e202303635. [PMID: 38055217 DOI: 10.1002/chem.202303635] [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: 11/02/2023] [Revised: 12/06/2023] [Accepted: 12/06/2023] [Indexed: 12/07/2023]
Abstract
Covalently-linked chromophore-radical systems with their unique optical and magnetic properties are useful for applications in, e. g., quantum information science. To expand the catalog of molecular systems, we synthesized and characterized six novel chromophore-radical and radical-chromophore-radical systems employing derivatives of perylene diimide (PDI) as the chromophore and trityl as the radical. The EPR properties of these compounds were evaluated in solution at cryogenic and room temperatures. In addition, the electron spin-spin coupling in the two bistrityl systems was investigated using DQC measurements. The presented results serve as a basis for further spectroscopic investigations under photoexcitation of the PDI core.
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Affiliation(s)
- Kevin Kopp
- Clausius-Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53115, Bonn, Germany
| | - Lars Westhofen
- Clausius-Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53115, Bonn, Germany
| | - Tobias Hett
- Clausius-Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53115, Bonn, Germany
| | | | - Maximilian Mayländer
- Institute of Physical Chemistry, University of Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Sabine Richert
- Institute of Physical Chemistry, University of Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Olav Schiemann
- Clausius-Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53115, Bonn, Germany
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7
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Qiu Y, Eckvahl HJ, Equbal A, Krzyaniak MD, Wasielewski MR. Enhancing Coherence Times of Chromophore-Radical Molecular Qubits and Qudits by Rational Design. J Am Chem Soc 2023; 145:25903-25909. [PMID: 37963349 DOI: 10.1021/jacs.3c10772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
An important criterion for quantum operations is long qubit coherence times. To elucidate the influence of molecular structure on the coherence times of molecular spin qubits and qudits, a series of molecules featuring perylenediimide (PDI) chromophores covalently linked to stable nitroxide radicals were synthesized and investigated by pulse electron paramagnetic resonance spectroscopy. Photoexcitation of PDI in these systems creates an excited quartet state (Q) followed by a spin-polarized doublet ground state (D0), which hold promise as spin qudits and qubits, respectively. By tailoring the molecular structure of these spin qudit/qubit candidates by selective deuteration and eliminating intramolecular motion, coherence times of Tm = 9.1 ± 0.3 and 4.2 ± 0.3 μs at 85 K for D0 and Q, respectively, are achieved. These coherence times represent a nearly 3-fold enhancement compared to those of the initial molecular design. This approach offers a rational structural design protocol for effectively extending coherence times in molecular spin qudits/qubits.
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Affiliation(s)
- Yunfan Qiu
- Department of Chemistry, Center for Molecular Quantum Transduction, and Paula M. Trienens Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
| | - Hannah J Eckvahl
- Department of Chemistry, Center for Molecular Quantum Transduction, and Paula M. Trienens Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
| | - Asif Equbal
- Department of Chemistry, Center for Molecular Quantum Transduction, and Paula M. Trienens Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
| | - Matthew D Krzyaniak
- Department of Chemistry, Center for Molecular Quantum Transduction, and Paula M. Trienens Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
| | - Michael R Wasielewski
- Department of Chemistry, Center for Molecular Quantum Transduction, and Paula M. Trienens Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
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