Magnetic properties and hyperfine interactions in Cr8, Cr7Cd, and Cr7Ni molecular rings from 19F-NMR

Bordonali, Lorenzo; Garlatti, Elena; Casadei, Cecilia M.; Furukawa, Yuji; Lascialfari, A.; Carretta, S.; Troiani, Filippo; Timco, Grigore A.; Winpenny, Richard E. P.; Borsa, F.

doi:10.1063/1.4870469

Cited by 4 publications

(3 citation statements)

References 39 publications

(95 reference statements)

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“…Solid-state 19 FNMR spectroscopy performed on single crystals of 2, 3-Ni,and 3-Cd has also been reported. [52] For 2, at low magnetic fields,asingle narrow resonance is seen at the Larmor frequency for 19 F, as expected because,o wing to symmetry,the <s i >= 0inthe S = 0ground state and there is no hyperfine interaction. As the magnetic field is increased parallel to the plane of the ring, four resonances are observed as <s i > becomes non-zero through increasing population of the M = À1c omponent of the S = 1f irst excited state.T he four signals correspond to the magnetically non-equivalent sites (with anisoptropic hyperfine couplings) with the applied field in the plane of the ring.…”

Section: Angewandte Reviewssupporting

confidence: 70%

“…Solid‐state 19 F NMR spectroscopy performed on single crystals of 2 , 3‐Ni , and 3‐Cd has also been reported 52. For 2 , at low magnetic fields, a single narrow resonance is seen at the Larmor frequency for 19 F, as expected because, owing to symmetry, the ${ \char60 }$ s i >=0 in the S =0 ground state and there is no hyperfine interaction.…”

Section: Physical Studies Of Single Heterometallic Ringsmentioning

confidence: 71%

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Heterometallic Rings: Their Physics and use as Supramolecular Building Blocks

et al. 2015

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An enormous family of heterometallic rings has been made. The first were Cr7 M rings where M = Ni(II), Zn(II), Mn(II), and rings have been made with as many as fourteen metal centers in the cyclic structure. They are bridged externally by carboxylates, and internally by fluorides or a penta-deprotonated polyol. The size of the rings is controlled through templates which have included a range of ammonium or imidazolium ions, alkali metals and coordination compounds. The rings can be functionalized to act as ligands, and incorporated into hybrid organic-inorganic rotaxanes and into molecules containing up to 200 metal centers. Physical studies reported include: magnetic measurements, inelastic neutron scattering (including single crystal measurements), electron paramagnetic resonance spectroscopy (including measurements of phase memory times), NMR spectroscopy (both solution and solid state), and polarized neutron diffraction. The rings are hence ideal for understanding magnetism in elegant exchange-coupled systems.

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Section: Angewandte Reviewssupporting

confidence: 70%

Section: Physical Studies Of Single Heterometallic Ringsmentioning

confidence: 71%

Heterometallic Rings: Their Physics and use as Supramolecular Building Blocks

et al. 2015

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“…Transverse relaxation measurements, 1/T 2 , were performed by using a standard π/2 x -π/2 y pulse sequence. 1 H NMR spectra were collected by using the magnetic field sweep technique 31 at three different fixed Larmor frequencies corresponding to magnetic fields smaller (51.1 MHz) and larger (234.16 MHz) than the first ground state level crossing, and at a field (340.6 MHz) larger than the second ground state level crossing.…”

Section: A Experimental Methodsmentioning

confidence: 99%

Low temperature magnetic properties and spin dynamics in single crystals of Cr8Zn antiferromagnetic molecular rings

Adelnia

Chiesa

Bordignon

et al. 2015

The Journal of Chemical Physics

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Articles you may be interested inHigh temperature spin dynamics in linear magnetic chains, molecular rings, and segments by nuclear magnetic resonance J. Appl. Phys. 117, 17B308 (2015) A detailed experimental investigation of the effects giving rise to the magnetic energy level structure in the vicinity of the level crossing (LC) at low temperature is reported for the open antiferromagnetic molecular ring Cr 8 Zn. The study is conducted by means of thermodynamic techniques (torque magnetometry, magnetization and specific heat measurements) and microscopic techniques (nuclear magnetic resonance line width, nuclear spin lattice, and spin-spin relaxation measurements). The experimental results are shown to be in excellent agreement with theoretical calculations based on a minimal spin model Hamiltonian, which includes a Dzyaloshinskii-Moriya interaction. The first ground state level crossing at µ 0 H c1 = 2.15 T is found to be an almost true LC while the second LC at µ 0 H c2 = 6.95 T has an anti-crossing gap of ∆ 12 = 0.19 K. In addition, both NMR and specific heat measurements show the presence of a level anti-crossing between excited states at µ 0 H = 4.5 T as predicted by the theory. In all cases, the fit of the experimental data is improved by introducing a distribution of the isotropic exchange couplings (J), i.e., using a J strain model. The peaks at the first and second LCs in the nuclear spin-lattice relaxation rate are dominated by inelastic scattering and a value of Γ ∼ 10 10 rad/s is inferred for the life time broadening of the excited state of the open ring, due to spin phonon interaction. A loss of NMR signal (wipe-out effect) is observed for the first time at LC and is explained by the enhancement of the spin-spin relaxation rate due to the inelastic scattering. C 2015 AIP Publishing LLC. [http://dx

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