Skip to main content

Federico Totti

University of Florence, Chemistry, Faculty Member

Followers

33

Following

20

Co-authors

15

Public Views

Born in Florence in 1971, Federico Totti graduated in Chemistry on July 1995 at the University of Florence where he got his PhD in Science and Technology of Materials with prof. Alessandro Bencini. He became Research Associate in 2006, Adjunt Professor in 2009, and Associate professor in 2017. He holds courses for Master degree students in Chemistry and bachelor degree students in Physics and Astrophysics.

less

The University of Manchester

University of Tunis El Manar

Martin McBriarty

Pacific Northwest National Laboratory

Arizona State University

Thomas B. Faust

The University of Sydney

Pooria Farahani

KTH Royal Institute of Technology

University of California, Riverside

Susan Herringer

University of Bern

Ludovic Bellot-Gurlet

Sorbonne Université

Boston University

InterestsView All (7)

Uploads

Papers by Federico Totti

The chimera of 2D- and 1D-graphene magnetization by hydrogenation or fluorination: critically revisiting old schemes and proposing new ones by <i>ab initio</i> methods

Nanoscale advances, Dec 31, 2023

Graphene is an ideal candidate material for spintronics due to its layered structure and peculiar... more Graphene is an ideal candidate material for spintronics due to its layered structure and peculiar electronic structure. However, in its pristine state, the production of magnetic moments is not trivial. A very appealing approach is the chemical modification of pristine graphene. The main obstacle is the control of the geometrical features and the selectivity of functional groups. The lack of a periodic functionalization pattern of the graphene sheet prevents, therefore, the achievement of long-range magnetic order, thus limiting its use in spintronic devices. In such regards, the stability and the magnitude of the instilled magnetic moment depending on the size and shape of in silico designed graphane islands and ribbons embedded in graphene matrix will be computed and analysed. Our findings thus suggest that a novel and magneto-active graphene derivative nanostructure could become achievable more easily than extended graphone or nanoribbons, with a strong potential for future spintronics applications with a variable spin-current density.

The chimera of 2D-and 1D-graphene magnetization by hydrogenation or fluorination: critically revisiting old schemes and proposing new ones by ab initio methods

Graphene is an ideal candidate material for spintronics due to its layered structure and peculiar... more Graphene is an ideal candidate material for spintronics due to its layered structure and peculiar electronic structure. However, in its pristine state, the production of magnetic moments is not trivial. A very appealing approach is the chemical modification of pristine graphene. The main obstacle is the control of the geometrical features and the selectivity of functional groups. The lack of a periodic functionalization pattern of the graphene sheet prevents, therefore, the achievement of long-range magnetic order, thus limiting its use in spintronic devices. In such regards, the stability and the magnitude of the instilled magnetic moment depending on the size and shape of in silico-designed graphane islands and ribbons embedded in graphene matrix will be computed and analysed. Our findings thus suggest that a novel and magneto-active graphene derivative nanostructure could become achievable more easily than extended graphone or nanoribbons, with a strong potential for future spintronics applications with a variable spin-current density.

The critical role of ultra-low-energy vibrations in the relaxation dynamics of molecular qubits

Nature Communications, Mar 24, 2023

Highly Axial Magnetic Anisotropy in a N<sub>3</sub>O<sub>5</sub>Dysprosium(III) Coordination Environment Generated by a Merocyanine Ligand

Chemistry: A European Journal, Sep 21, 2016

A spiropyran-based switchable ligand isomerizes upon reaction with lanthanide(III) precursors to ... more A spiropyran-based switchable ligand isomerizes upon reaction with lanthanide(III) precursors to generate complexes with unusual N 3 O 5 coordination sphere. The air stable dysprosium(III) complex shows a hysteresis loop at 2 K and a very strong axial magnetic anisotropy generated by the merocyanine phenolate donor. 12-BS07-0010-01)). G.F.G gratefully acknowledges the European Commission through the ERC-AdG 267746 MolNanoMas (project n. 267746) and the ANR (ANR-13-BS07-0022-01) for financial support. B.L.G. and G.F.G. thank the French GENCI/IDRIS-CINES center for high-performance computing resources.

Magnetic Anisotropy Trends along a Full 4f-Series: The <i>f</i><sup><i>n</i>+7</sup> Effect

Journal of the American Chemical Society, May 24, 2021

The combined experimental and computational study of the 13 magnetic complexes belonging to the N... more The combined experimental and computational study of the 13 magnetic complexes belonging to the Na[LnDOTA(H 2 O)] (H 4 DOTA = tetraazacyclododecane-N,N′,N″,N‴-tetraacetic acid and Ln = Ce−Yb) family allowed us to identify a new trend: the orientation of the magnetic anisotropy tensors of derivatives differing by seven f electrons practically coincide. We name this trend the f n+7 effect. Experiments and theory fully agree on the match between the magnetic reference frames (e.g., the easy, intermediate, and hard direction). The shape of the magnetic anisotropy of some couples of ions differing by seven f electrons might seem instead different at first look, but our analysis explains a hidden similarity. We thus pave the way toward a reliable predictivity of the magnetic anisotropy of lanthanide complexes with a consequent reduced need of computational and synthetical efforts. We also offer a way to gain information on ions with a relatively small total angular momentum (i.e., Sm 3+ and Eu 3+) and on the radioactive Pm 3+ , which are difficult to investigate experimentally.

Improved slow magnetic relaxation in optically pure helicene-based Dy<sup>III</sup> single molecule magnets

Chemical Communications, 2016

Giant spin–phonon bottleneck effects in evaporable vanadyl-based molecules with long spin coherence

Dalton Transactions, 2016

Mixed-Sandwich Titanium(III) Qubits on Au(111): Electron Delocalization Ruled by Molecular Packing

Nano Letters, Oct 18, 2022

Organometallic sandwich complexes are versatile molecular systems that have been recently employe... more Organometallic sandwich complexes are versatile molecular systems that have been recently employed for single-molecule manipulation and spin sensing experiments. Among related organometallic compounds, the mixed-sandwich S = 1/2 complex (η 8-cyclooctatetraene)(η 5-cyclopentadienyl)titanium, here [CpTi(cot)], has attracted interest as a spin qubit because of the long coherence time. Here the structural and chemical properties of [CpTi(cot)] on Au(111) are investigated at the monolayer level by experimental and computational methods. Scanning tunneling microscopy suggests that adsorption occurs in two molecular orientations, lying and standing, with a 3:1 ratio. XPS data evidence that a fraction of the molecules undergo partial electron transfer to gold, while our computational analysis suggests that only the standing molecules experience charge delocalization toward the surface. Such a phenomenon depends on intermolecular interactions that stabilize the molecular packing in the monolayer. This orientationdependent molecule−surface hybridization opens exciting perspectives for selective control of the molecule−substrate spin delocalization in hybrid interfaces.

An exchange coupled <i>meso</i>–<i>meso</i> linked vanadyl porphyrin dimer for quantum information processing

Chemical Science, 2023

We report here the synthesis of a new meso-meso (m-m) singly linked vanadyl-porphyrin dimer that ... more We report here the synthesis of a new meso-meso (m-m) singly linked vanadyl-porphyrin dimer that crystallizes in two different pseudo-polymorphs. The single crystal continuous-wave electron paramagnetic resonance investigation evidences a small but crucial isotropic exchange interaction, J, between the two tilted, and thus distinguishable, spin centers of the order of 10 −2 cm −1. The experimental and DFT studies evidence a correlation between J values and porphyrin plane tilting angle and distortion. Pulsed EPR analysis shows that the two vanadyl dimers maintain the coherence time of the monomer. With the obtained spin Hamiltonian parameters, we identify suitable transitions that could be used as computational basis states. Our results, coupled with the evaporability of porphyrin systems, establish this class of dimers as extremely promising for quantum information processing applications.

Cover Feature: Magnetic Slow Relaxation in a Metal-Organic Framework Made of Chains of Ferromagnetically Coupled Single-Molecule Magnets (Chem. Eur. J. 27/2018)

Chemistry: A European Journal, Apr 16, 2018

We report the study of a Dy-based metal-organic framework (MOF), with unprecedented magnetic prop... more We report the study of a Dy-based metal-organic framework (MOF), with unprecedented magnetic properties. The compound is made of nine-coordinated Dy III magnetic building blocks (MBBs) with poor intrinsic single-molecule magnet behaviour. However, the MOF architecture constrains the MBBs in a onedimensional structure that induces a ferromagnetic coupling between them. Overall, the material shows a magnetic slow relaxation in absence of external static field and a hysteretic behaviour at 0.5K. Low temperature magnetic studies, diamagnetic doping and ab-initio calculations highlight the crucial role played by the Dy-Dy ferromagnetic interaction. Overall, we report an original magnetic object at the frontier between single-chain magnet and singlemolecule magnet that host intra-chain couplings that cancel quantum tunneling between the MBBs. This compound evidences that bottom-up approach via MOF design can induce spontaneous organization of MBBs able to produce remarkable molecular magnetic material.

Lanthanide complexes involving multichelating TTF-based ligands

Inorganic chemistry frontiers, 2017

The reaction between the 2-{TTF-fused-1H-benzimidazol-2-yl}pyridine alkylated either with the di-... more The reaction between the 2-{TTF-fused-1H-benzimidazol-2-yl}pyridine alkylated either with the di-(pyrazol-1-yl)-4-pyridyl (L 1) or dimethyl-2,2'-bipyridine (L 2) moiety and 1 equiv. of Ln(hfac)32H2O (Ln III = Dy III and Yb III) leads to three dinuclear complexes of formula [Yb2(hfac)6(L 1)]2(CH2Cl2)•C6H14 (1) and [Ln2(hfac)6(L 2)]CH2Cl2 (Ln III = Yb III (2) and Dy III (3)). The X-ray structures highlight square antiprism (D4d symmetry) and spherical tricapped trigonal prism (D3h) for the eight-and ninecoordinated lanthanide ions, respectively. Irradiation of the lowest-energy HOMO  LUMO ILCT absorption band induced a 2 F5/2  2 F7/2 Yb-centered emission for 1 and 2. Both Yb III ions displayed similar emissions in 2 while two distinct emissions were observed and attributed to the two Yb III ions in 1 depending on their coordination surroundings. Slow magnetic relaxation is detected by dynamic magnetic measurements for 3 with a measured relaxation time 0 = 3.7(1.3) x 10-7 s and an energy barrier  = 39.6(2) cm-1. Taking into account the environment of both Dy III ions in 3, it was expected that both metallic centers displayed similar dynamic magnetic behavior. The latter was rationalized by ab initio CASSCF/SI-SO calculations.

A Dy <sub>4</sub> Cubane: A New Member in the Single‐Molecule Toroics Family

Angewandte Chemie, Nov 27, 2018

An Exchange Coupled meso-meso Linked Vanadyl Porphyrin Dimer for Quantum Information Processing

We report here the synthesis of a new meso-meso (m-m) singly linked vanadyl-porphyrin dimer that ... more We report here the synthesis of a new meso-meso (m-m) singly linked vanadyl-porphyrin dimer that crystallizes in two different pseudo-polymorphs. The single crystal continuous-wave electron paramagnetic resonance investigation evidences a small but crucial isotropic exchange interaction, J, between the two tilted, and thus distinguishable, spin centers of the order of 10 −2 cm −1. The experimental and DFT studies evidence a correlation between J values and porphyrin plane tilting angle and distortion. Pulsed EPR analysis shows that the two vanadyl dimers maintain the coherence time of the monomer. With the obtained spin Hamiltonian parameters, we identify suitable transitions that could be used as computational basis states. Our results, coupled with the evaporability of porphyrin systems, establish this class of dimers as extremely promising for quantum information processing applications.

Tetrathiafulvalene-Based Helicene Ligand in the Design of a Dysprosium Field-Induced Single-Molecule Magnet

Inorganic Chemistry, Dec 14, 2018

The design of a coordination complex which involves a ligand combining both a tetrathiafulvalene ... more The design of a coordination complex which involves a ligand combining both a tetrathiafulvalene core and helicene fragment was achieved thanks to the reaction between the new 2-{1-[2-methyl[6]helicene]-4,5-[4,5-bis(propylthio)tetrathiafulvalenyl]-1H-benzimidazol-2-yl}pyridine ligand (L) and the Dy(hfac) 3 ⋅2H 2 O metallo precursor. Magnetic investigations showed a field-induced Single-Molecule Magnet (SMM) behavior under an applied magnetic field of 1000 Oe for [Dy(hfac) 3 (L)]⋅0.5CH 2 Cl 2 while experimental oriented single crystal magnetic measurements allowed for the determination of the magnetic anisotropy orientation. The magnetic behavior was rationalized based on ab initio CASSCF/SI-SO calculations. This redox-active chiral field-induced SMM paves the route for designing switchable multi-properties SMMs.

Correction: An exchange coupled <i>meso</i>–<i>meso</i> linked vanadyl porphyrin dimer for quantum information processing

Chemical Science, 2023

Correction for 'An exchange coupled meso-meso linked vanadyl porphyrin dimer for quantum informat... more Correction for 'An exchange coupled meso-meso linked vanadyl porphyrin dimer for quantum information processing' by Davide Ranieri et al., Chem. Sci., 2022, https://doi.org/10.1039/d2sc04969d. During the editorial production of the nished article, the graphics associated with Fig. 3(a) and (b) were inadvertently switched. The intended version of Fig. 3 is shown below, and replaces that of the original article: The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers. Fig. 3 Room temperature angular-dependent CW EPR X-band spectra of (a) m-[VO(TrPP)] 2 and (b) o-[VO(TrPP)] 2 for crystal rotations around three orthogonal axes. For both panels, the upper row shows the 2D experimental EPR contour plots for the three rotations, acquired with a 3°s tep; the lower row shows representative EPR spectra (black lines) for the three rotationsfrom 0°to 180°every 15°-together with the best spectral simulations (red lines) obtained by using |J| = 0.01 (0.005) cm −1 and |J| = 0.05 (0.01) cm −1 for (a) and (b), respectively. Experimental frequency: 9.40 GHz for (a), 9.87 GHz for (b).

Redox-Active Dysprosium Single-Molecule Magnet: Spectro-Electrochemistry and Theoretical Investigations

Magnetochemistry, Aug 2, 2019

The mononuclear single-molecule magnet (SMM) [Dy(tta) 3 (L)]•C 6 H 14 (1) (where tta − = 2-thenoy... more The mononuclear single-molecule magnet (SMM) [Dy(tta) 3 (L)]•C 6 H 14 (1) (where tta − = 2-thenoyltrifluoroacetonate and L = 4,5-bis(propylthio)-tetrathiafulvalene-2-(2-pyridyl)benzimidazolemethyl-2-pyridine) was studied by spectro-electrochemistry. The resulting electronic spectra of the three oxidation states 1, 1 + •, and 1 2+ were rationalized by time-dependent density functional theory (TD-DFT) calculations starting from the DFT optimized structures. The modulation of the magnetic anisotropy of the Dy III center upon oxidation was also inspected at the Complete Active Space Self-Consistent Field (CASSCF) level of calculation.

Complex H-bonded silanol network in zeolites revealed by IR and NMR spectroscopy combined with DFT calculations †

HAL (Le Centre pour la Communication Scientifique Directe), Oct 13, 2021

Granulicella tundricula hydroxynitrile lyase (GtHNL) is a manganese dependent cupin which catalys... more Granulicella tundricula hydroxynitrile lyase (GtHNL) is a manganese dependent cupin which catalyses the enantioselective synthesis of (R)-cyanohydrins. The GtHNL triple mutant A40H/V42T/Q110H, previously reported to exhibit a high activity and stability, was immobilised on Celite R-633 by adsorption. The synthesis of (R)-mandelonitrile catalysed by immobilised enzyme in a rotating bed reactor was compared to a continuous flow reactor. A batch reaction was used as reference system and organic solvent (MTBE) was used as reaction medium to suppress the chemical background reaction, ensuring the synthesis of enantiopure cyanohydrin. The rotating bed reactor, designed to boost conversion rates due to enhanced mass transfer, did not greatly enhance the reaction displaying a rate 1.7 times higher than the reference batch model. Moreover, similar conversion (96% after 4 hours) and recyclability were observed as compared to the reference system. The continuous flow reactor displayed rates 2 and 3 times higher than the rotating bed and the reference batch systems, respectively. Good conversions were achieved within minutes (97% conversion in 4 minutes at 0.1 mL/min). The immobilised enzyme displayed excellent enantioselectivity and high operational stability under all evaluated conditions. Overall, GtHNL triple mutant A40H/V42T/Q110H immobilised on Celite R-633 is an excellent catalyst for the synthesis of (R)-mandelonitrile with a great potential for continuous flow production of cyanohydrins.

Enhanced Vapor-Phase Processing in Fluorinated Fe<sub>4</sub> Single-Molecule Magnets

Inorganic Chemistry, May 9, 2013

Engineering Chemisorption of Fe4 Single‐Molecule Magnets on Gold

Advanced Materials Interfaces, 2021

Gaining control over the grafting geometry is critically important for any application of surface... more Gaining control over the grafting geometry is critically important for any application of surface‐supported single‐molecule magnets (SMMs) in data storage, spintronics, and quantum information science. Here, tetrairon(III) SMMs with a propeller‐like structure are functionalized with thioacetyl‐terminated alkyl chains to promote chemisorption on gold surfaces from solution and to evaluate differences in adsorption geometry and magnetic properties as a function of chain length. The prepared monolayers are investigated using X‐ray absorption techniques with linearly and circularly polarized light to extract geometrical and magnetic information, respectively. All derivatives remain intact and form partially oriented monolayers on the gold surface. A ligand‐field analysis of the observed X‐ray natural linear dichroism shows that the threefold molecular axis is invariably biased toward the surface normal, in agreement with ab initio calculations. This preferential orientation is most pron...

First coordination compounds based on a bis(imino nitroxide) biradical and 4f metal ions: synthesis, crystal structures and magnetic properties

Dalton transactions (Cambridge, England : 2003), Jan 11, 2016

The synthesis, crystal structures and magnetic properties of two families of heterospin complexes... more The synthesis, crystal structures and magnetic properties of two families of heterospin complexes containing lanthanide ions and a bis(imino nitroxide) biradical (IPhIN = 1-iodo-3,5-bis(4',4',5',5'-tetramethyl-4',5'-dihydro-1H-imidazole-1'-oxyl)benzene) are reported: in [Ln2(hfac)6(IPhIN)(H2O)2] compounds, two lanthanide ions [Ln = Gd(III) () and Dy(III) ()] are coordinated to the biradical, and in [Ln(hfac)3(IPhIN)(H2O)] compounds, one lanthanide ion (Ln = Tb(III) (), Gd(III) () or Dy(III) ()) is coordinated to the biradical. Ferromagnetic intramolecular magnetic interactions between Gd(III) and the biradical were found for and , while intramolecular magnetic interactions between the radicals were ferro- and antiferromagnetic, respectively. Compound shows a field induced slow relaxation of magnetization, which (under an external applied field of 2 kOe) exhibits an activation energy barrier of ΔE/kB = 27 K and a pre-exponential factor of 1.4 × 10(-8) s. T...

The chimera of 2D- and 1D-graphene magnetization by hydrogenation or fluorination: critically revisiting old schemes and proposing new ones by <i>ab initio</i> methods

Nanoscale advances, Dec 31, 2023

Graphene is an ideal candidate material for spintronics due to its layered structure and peculiar... more Graphene is an ideal candidate material for spintronics due to its layered structure and peculiar electronic structure. However, in its pristine state, the production of magnetic moments is not trivial. A very appealing approach is the chemical modification of pristine graphene. The main obstacle is the control of the geometrical features and the selectivity of functional groups. The lack of a periodic functionalization pattern of the graphene sheet prevents, therefore, the achievement of long-range magnetic order, thus limiting its use in spintronic devices. In such regards, the stability and the magnitude of the instilled magnetic moment depending on the size and shape of in silico designed graphane islands and ribbons embedded in graphene matrix will be computed and analysed. Our findings thus suggest that a novel and magneto-active graphene derivative nanostructure could become achievable more easily than extended graphone or nanoribbons, with a strong potential for future spintronics applications with a variable spin-current density.

The chimera of 2D-and 1D-graphene magnetization by hydrogenation or fluorination: critically revisiting old schemes and proposing new ones by ab initio methods

Graphene is an ideal candidate material for spintronics due to its layered structure and peculiar... more Graphene is an ideal candidate material for spintronics due to its layered structure and peculiar electronic structure. However, in its pristine state, the production of magnetic moments is not trivial. A very appealing approach is the chemical modification of pristine graphene. The main obstacle is the control of the geometrical features and the selectivity of functional groups. The lack of a periodic functionalization pattern of the graphene sheet prevents, therefore, the achievement of long-range magnetic order, thus limiting its use in spintronic devices. In such regards, the stability and the magnitude of the instilled magnetic moment depending on the size and shape of in silico-designed graphane islands and ribbons embedded in graphene matrix will be computed and analysed. Our findings thus suggest that a novel and magneto-active graphene derivative nanostructure could become achievable more easily than extended graphone or nanoribbons, with a strong potential for future spintronics applications with a variable spin-current density.

The critical role of ultra-low-energy vibrations in the relaxation dynamics of molecular qubits

Nature Communications, Mar 24, 2023

Highly Axial Magnetic Anisotropy in a N<sub>3</sub>O<sub>5</sub>Dysprosium(III) Coordination Environment Generated by a Merocyanine Ligand

Chemistry: A European Journal, Sep 21, 2016

A spiropyran-based switchable ligand isomerizes upon reaction with lanthanide(III) precursors to ... more A spiropyran-based switchable ligand isomerizes upon reaction with lanthanide(III) precursors to generate complexes with unusual N 3 O 5 coordination sphere. The air stable dysprosium(III) complex shows a hysteresis loop at 2 K and a very strong axial magnetic anisotropy generated by the merocyanine phenolate donor. 12-BS07-0010-01)). G.F.G gratefully acknowledges the European Commission through the ERC-AdG 267746 MolNanoMas (project n. 267746) and the ANR (ANR-13-BS07-0022-01) for financial support. B.L.G. and G.F.G. thank the French GENCI/IDRIS-CINES center for high-performance computing resources.

Magnetic Anisotropy Trends along a Full 4f-Series: The <i>f</i><sup><i>n</i>+7</sup> Effect

Journal of the American Chemical Society, May 24, 2021

The combined experimental and computational study of the 13 magnetic complexes belonging to the N... more The combined experimental and computational study of the 13 magnetic complexes belonging to the Na[LnDOTA(H 2 O)] (H 4 DOTA = tetraazacyclododecane-N,N′,N″,N‴-tetraacetic acid and Ln = Ce−Yb) family allowed us to identify a new trend: the orientation of the magnetic anisotropy tensors of derivatives differing by seven f electrons practically coincide. We name this trend the f n+7 effect. Experiments and theory fully agree on the match between the magnetic reference frames (e.g., the easy, intermediate, and hard direction). The shape of the magnetic anisotropy of some couples of ions differing by seven f electrons might seem instead different at first look, but our analysis explains a hidden similarity. We thus pave the way toward a reliable predictivity of the magnetic anisotropy of lanthanide complexes with a consequent reduced need of computational and synthetical efforts. We also offer a way to gain information on ions with a relatively small total angular momentum (i.e., Sm 3+ and Eu 3+) and on the radioactive Pm 3+ , which are difficult to investigate experimentally.

Improved slow magnetic relaxation in optically pure helicene-based Dy<sup>III</sup> single molecule magnets

Chemical Communications, 2016

Giant spin–phonon bottleneck effects in evaporable vanadyl-based molecules with long spin coherence

Dalton Transactions, 2016

Mixed-Sandwich Titanium(III) Qubits on Au(111): Electron Delocalization Ruled by Molecular Packing

Nano Letters, Oct 18, 2022

Organometallic sandwich complexes are versatile molecular systems that have been recently employe... more Organometallic sandwich complexes are versatile molecular systems that have been recently employed for single-molecule manipulation and spin sensing experiments. Among related organometallic compounds, the mixed-sandwich S = 1/2 complex (η 8-cyclooctatetraene)(η 5-cyclopentadienyl)titanium, here [CpTi(cot)], has attracted interest as a spin qubit because of the long coherence time. Here the structural and chemical properties of [CpTi(cot)] on Au(111) are investigated at the monolayer level by experimental and computational methods. Scanning tunneling microscopy suggests that adsorption occurs in two molecular orientations, lying and standing, with a 3:1 ratio. XPS data evidence that a fraction of the molecules undergo partial electron transfer to gold, while our computational analysis suggests that only the standing molecules experience charge delocalization toward the surface. Such a phenomenon depends on intermolecular interactions that stabilize the molecular packing in the monolayer. This orientationdependent molecule−surface hybridization opens exciting perspectives for selective control of the molecule−substrate spin delocalization in hybrid interfaces.

An exchange coupled <i>meso</i>–<i>meso</i> linked vanadyl porphyrin dimer for quantum information processing

Chemical Science, 2023

We report here the synthesis of a new meso-meso (m-m) singly linked vanadyl-porphyrin dimer that ... more We report here the synthesis of a new meso-meso (m-m) singly linked vanadyl-porphyrin dimer that crystallizes in two different pseudo-polymorphs. The single crystal continuous-wave electron paramagnetic resonance investigation evidences a small but crucial isotropic exchange interaction, J, between the two tilted, and thus distinguishable, spin centers of the order of 10 −2 cm −1. The experimental and DFT studies evidence a correlation between J values and porphyrin plane tilting angle and distortion. Pulsed EPR analysis shows that the two vanadyl dimers maintain the coherence time of the monomer. With the obtained spin Hamiltonian parameters, we identify suitable transitions that could be used as computational basis states. Our results, coupled with the evaporability of porphyrin systems, establish this class of dimers as extremely promising for quantum information processing applications.

Cover Feature: Magnetic Slow Relaxation in a Metal-Organic Framework Made of Chains of Ferromagnetically Coupled Single-Molecule Magnets (Chem. Eur. J. 27/2018)

Chemistry: A European Journal, Apr 16, 2018

We report the study of a Dy-based metal-organic framework (MOF), with unprecedented magnetic prop... more We report the study of a Dy-based metal-organic framework (MOF), with unprecedented magnetic properties. The compound is made of nine-coordinated Dy III magnetic building blocks (MBBs) with poor intrinsic single-molecule magnet behaviour. However, the MOF architecture constrains the MBBs in a onedimensional structure that induces a ferromagnetic coupling between them. Overall, the material shows a magnetic slow relaxation in absence of external static field and a hysteretic behaviour at 0.5K. Low temperature magnetic studies, diamagnetic doping and ab-initio calculations highlight the crucial role played by the Dy-Dy ferromagnetic interaction. Overall, we report an original magnetic object at the frontier between single-chain magnet and singlemolecule magnet that host intra-chain couplings that cancel quantum tunneling between the MBBs. This compound evidences that bottom-up approach via MOF design can induce spontaneous organization of MBBs able to produce remarkable molecular magnetic material.

Lanthanide complexes involving multichelating TTF-based ligands

Inorganic chemistry frontiers, 2017

The reaction between the 2-{TTF-fused-1H-benzimidazol-2-yl}pyridine alkylated either with the di-... more The reaction between the 2-{TTF-fused-1H-benzimidazol-2-yl}pyridine alkylated either with the di-(pyrazol-1-yl)-4-pyridyl (L 1) or dimethyl-2,2'-bipyridine (L 2) moiety and 1 equiv. of Ln(hfac)32H2O (Ln III = Dy III and Yb III) leads to three dinuclear complexes of formula [Yb2(hfac)6(L 1)]2(CH2Cl2)•C6H14 (1) and [Ln2(hfac)6(L 2)]CH2Cl2 (Ln III = Yb III (2) and Dy III (3)). The X-ray structures highlight square antiprism (D4d symmetry) and spherical tricapped trigonal prism (D3h) for the eight-and ninecoordinated lanthanide ions, respectively. Irradiation of the lowest-energy HOMO  LUMO ILCT absorption band induced a 2 F5/2  2 F7/2 Yb-centered emission for 1 and 2. Both Yb III ions displayed similar emissions in 2 while two distinct emissions were observed and attributed to the two Yb III ions in 1 depending on their coordination surroundings. Slow magnetic relaxation is detected by dynamic magnetic measurements for 3 with a measured relaxation time 0 = 3.7(1.3) x 10-7 s and an energy barrier  = 39.6(2) cm-1. Taking into account the environment of both Dy III ions in 3, it was expected that both metallic centers displayed similar dynamic magnetic behavior. The latter was rationalized by ab initio CASSCF/SI-SO calculations.

A Dy <sub>4</sub> Cubane: A New Member in the Single‐Molecule Toroics Family

Angewandte Chemie, Nov 27, 2018

An Exchange Coupled meso-meso Linked Vanadyl Porphyrin Dimer for Quantum Information Processing

We report here the synthesis of a new meso-meso (m-m) singly linked vanadyl-porphyrin dimer that ... more We report here the synthesis of a new meso-meso (m-m) singly linked vanadyl-porphyrin dimer that crystallizes in two different pseudo-polymorphs. The single crystal continuous-wave electron paramagnetic resonance investigation evidences a small but crucial isotropic exchange interaction, J, between the two tilted, and thus distinguishable, spin centers of the order of 10 −2 cm −1. The experimental and DFT studies evidence a correlation between J values and porphyrin plane tilting angle and distortion. Pulsed EPR analysis shows that the two vanadyl dimers maintain the coherence time of the monomer. With the obtained spin Hamiltonian parameters, we identify suitable transitions that could be used as computational basis states. Our results, coupled with the evaporability of porphyrin systems, establish this class of dimers as extremely promising for quantum information processing applications.

Tetrathiafulvalene-Based Helicene Ligand in the Design of a Dysprosium Field-Induced Single-Molecule Magnet

Inorganic Chemistry, Dec 14, 2018

The design of a coordination complex which involves a ligand combining both a tetrathiafulvalene ... more The design of a coordination complex which involves a ligand combining both a tetrathiafulvalene core and helicene fragment was achieved thanks to the reaction between the new 2-{1-[2-methyl[6]helicene]-4,5-[4,5-bis(propylthio)tetrathiafulvalenyl]-1H-benzimidazol-2-yl}pyridine ligand (L) and the Dy(hfac) 3 ⋅2H 2 O metallo precursor. Magnetic investigations showed a field-induced Single-Molecule Magnet (SMM) behavior under an applied magnetic field of 1000 Oe for [Dy(hfac) 3 (L)]⋅0.5CH 2 Cl 2 while experimental oriented single crystal magnetic measurements allowed for the determination of the magnetic anisotropy orientation. The magnetic behavior was rationalized based on ab initio CASSCF/SI-SO calculations. This redox-active chiral field-induced SMM paves the route for designing switchable multi-properties SMMs.

Correction: An exchange coupled <i>meso</i>–<i>meso</i> linked vanadyl porphyrin dimer for quantum information processing

Chemical Science, 2023

Correction for 'An exchange coupled meso-meso linked vanadyl porphyrin dimer for quantum informat... more Correction for 'An exchange coupled meso-meso linked vanadyl porphyrin dimer for quantum information processing' by Davide Ranieri et al., Chem. Sci., 2022, https://doi.org/10.1039/d2sc04969d. During the editorial production of the nished article, the graphics associated with Fig. 3(a) and (b) were inadvertently switched. The intended version of Fig. 3 is shown below, and replaces that of the original article: The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers. Fig. 3 Room temperature angular-dependent CW EPR X-band spectra of (a) m-[VO(TrPP)] 2 and (b) o-[VO(TrPP)] 2 for crystal rotations around three orthogonal axes. For both panels, the upper row shows the 2D experimental EPR contour plots for the three rotations, acquired with a 3°s tep; the lower row shows representative EPR spectra (black lines) for the three rotationsfrom 0°to 180°every 15°-together with the best spectral simulations (red lines) obtained by using |J| = 0.01 (0.005) cm −1 and |J| = 0.05 (0.01) cm −1 for (a) and (b), respectively. Experimental frequency: 9.40 GHz for (a), 9.87 GHz for (b).

Redox-Active Dysprosium Single-Molecule Magnet: Spectro-Electrochemistry and Theoretical Investigations

Magnetochemistry, Aug 2, 2019

The mononuclear single-molecule magnet (SMM) [Dy(tta) 3 (L)]•C 6 H 14 (1) (where tta − = 2-thenoy... more The mononuclear single-molecule magnet (SMM) [Dy(tta) 3 (L)]•C 6 H 14 (1) (where tta − = 2-thenoyltrifluoroacetonate and L = 4,5-bis(propylthio)-tetrathiafulvalene-2-(2-pyridyl)benzimidazolemethyl-2-pyridine) was studied by spectro-electrochemistry. The resulting electronic spectra of the three oxidation states 1, 1 + •, and 1 2+ were rationalized by time-dependent density functional theory (TD-DFT) calculations starting from the DFT optimized structures. The modulation of the magnetic anisotropy of the Dy III center upon oxidation was also inspected at the Complete Active Space Self-Consistent Field (CASSCF) level of calculation.

Complex H-bonded silanol network in zeolites revealed by IR and NMR spectroscopy combined with DFT calculations †

HAL (Le Centre pour la Communication Scientifique Directe), Oct 13, 2021

Granulicella tundricula hydroxynitrile lyase (GtHNL) is a manganese dependent cupin which catalys... more Granulicella tundricula hydroxynitrile lyase (GtHNL) is a manganese dependent cupin which catalyses the enantioselective synthesis of (R)-cyanohydrins. The GtHNL triple mutant A40H/V42T/Q110H, previously reported to exhibit a high activity and stability, was immobilised on Celite R-633 by adsorption. The synthesis of (R)-mandelonitrile catalysed by immobilised enzyme in a rotating bed reactor was compared to a continuous flow reactor. A batch reaction was used as reference system and organic solvent (MTBE) was used as reaction medium to suppress the chemical background reaction, ensuring the synthesis of enantiopure cyanohydrin. The rotating bed reactor, designed to boost conversion rates due to enhanced mass transfer, did not greatly enhance the reaction displaying a rate 1.7 times higher than the reference batch model. Moreover, similar conversion (96% after 4 hours) and recyclability were observed as compared to the reference system. The continuous flow reactor displayed rates 2 and 3 times higher than the rotating bed and the reference batch systems, respectively. Good conversions were achieved within minutes (97% conversion in 4 minutes at 0.1 mL/min). The immobilised enzyme displayed excellent enantioselectivity and high operational stability under all evaluated conditions. Overall, GtHNL triple mutant A40H/V42T/Q110H immobilised on Celite R-633 is an excellent catalyst for the synthesis of (R)-mandelonitrile with a great potential for continuous flow production of cyanohydrins.

Enhanced Vapor-Phase Processing in Fluorinated Fe<sub>4</sub> Single-Molecule Magnets

Inorganic Chemistry, May 9, 2013

Engineering Chemisorption of Fe4 Single‐Molecule Magnets on Gold

Advanced Materials Interfaces, 2021

Gaining control over the grafting geometry is critically important for any application of surface... more Gaining control over the grafting geometry is critically important for any application of surface‐supported single‐molecule magnets (SMMs) in data storage, spintronics, and quantum information science. Here, tetrairon(III) SMMs with a propeller‐like structure are functionalized with thioacetyl‐terminated alkyl chains to promote chemisorption on gold surfaces from solution and to evaluate differences in adsorption geometry and magnetic properties as a function of chain length. The prepared monolayers are investigated using X‐ray absorption techniques with linearly and circularly polarized light to extract geometrical and magnetic information, respectively. All derivatives remain intact and form partially oriented monolayers on the gold surface. A ligand‐field analysis of the observed X‐ray natural linear dichroism shows that the threefold molecular axis is invariably biased toward the surface normal, in agreement with ab initio calculations. This preferential orientation is most pron...

First coordination compounds based on a bis(imino nitroxide) biradical and 4f metal ions: synthesis, crystal structures and magnetic properties

Dalton transactions (Cambridge, England : 2003), Jan 11, 2016

The synthesis, crystal structures and magnetic properties of two families of heterospin complexes... more The synthesis, crystal structures and magnetic properties of two families of heterospin complexes containing lanthanide ions and a bis(imino nitroxide) biradical (IPhIN = 1-iodo-3,5-bis(4',4',5',5'-tetramethyl-4',5'-dihydro-1H-imidazole-1'-oxyl)benzene) are reported: in [Ln2(hfac)6(IPhIN)(H2O)2] compounds, two lanthanide ions [Ln = Gd(III) () and Dy(III) ()] are coordinated to the biradical, and in [Ln(hfac)3(IPhIN)(H2O)] compounds, one lanthanide ion (Ln = Tb(III) (), Gd(III) () or Dy(III) ()) is coordinated to the biradical. Ferromagnetic intramolecular magnetic interactions between Gd(III) and the biradical were found for and , while intramolecular magnetic interactions between the radicals were ferro- and antiferromagnetic, respectively. Compound shows a field induced slow relaxation of magnetization, which (under an external applied field of 2 kOe) exhibits an activation energy barrier of ΔE/kB = 27 K and a pre-exponential factor of 1.4 × 10(-8) s. T...