Steering Metallofullerene Electron Spin in Porous Metal–Organic Framework

Abstract

Paramagnetic endohedral fullerenes are ideal candidates for quantum information processing and high-density data storage due to their protected spins with particularly high stability. Herein, we report a solid spin system based on a paramagnetic metallofullerene Y2@C79N through incarcerating it into the cage-shaped pores of a metal-organic framework (MOF-177). In this kind of guest and host complex, the Y2@C79N molecules inside the pores of MOF crystal show axisymmetric paramagnetic property. It was found that the pores of MOF-177 crystal play an important role in dispersing the Y2@C79N molecules as well as in steering their electron spin. The group of arranged Y2@C79N molecules and their electron spins in MOF crystals are potential quantum bits for quantum information science and data storage. Moreover, this kind of solid spin system can be used as a probe for nanoscale nuclear magnetic resonance or for motion imaging of a single biomolecule.

Single molecule magnet with an unpaired electron trapped between two lanthanide ions inside a fullerene

“…The large a ( 89 Y) values and significant anisotropy of both tensors indicate that a substantial degree of the spin density is localized evenly on the two Y atoms. The EPR parameters of Y 2 -I are very close to those reported earlier for Y 2 @C 79 N (refs 33, 40), proving that both molecules have very similar spin density distribution stemming from the single-occupied Y–Y bonding MO. DFT calculations confirm that the spin density in Y 2 -I is fully enclosed inside the carbon cage and resembles the spatial distribution of the Y–Y bonding MO (Supplementary Fig.…”

Spatial aromatic fences of metal–organic frameworks for manipulating the electron spin of a fulleropyrrolidine nitroxide radical

“…16 Of particular interest, the six-line splitting in the ESR spectra of 1@MOF-177 was a linear combination of an isotropic shape (referred to fast motion) with a iso value of 14.0 G and g iso factor of 2.0045 (gray line C 2 in Figure 5c), and an anisotropic one (referred to rigid motion) with a set of anisotropic parameters of a ‖ = 35.0 G, a⊥= 3.5 G, g ‖ = 2.0038, and g⊥ = 2.0005 (purple line C 1 in Figure 5c), which means that the anisotropic hyperfine spin Hamiltonian of the observed spectra, H obs , can be expressed as a superimposition of an anisotropic energy aniso = ⊥ ( x x + y y ) + ‖ z z and an isotropic energy iso = iso iso iso , where A refers to hyperfine coupling constant, S means spin angular momenta and I is nuclear spin. 10 From the simulated spectra listed in Figure 5d we can see clearly that the electron spin tensors in x and y orientations diminished gradually with temperature decreasing, meanwhile the electron spin in z component enhanced, which is in good agreement with the observed spectra.…”

“…9 More recently, we found a metalorganic framework (MOF-177) owns the ability to steer the electron spin of Y 2 @C 79 N by dispersing the spin-active molecules in its nano-sized pores. 10 Herein, we further demonstrated that the aperture size and spatial geometry of the host MOFs (MOF-177 and MIL-53) play an important role in tuning the electron spin associated with the spin dynamics of a model spin-active fullerene molecule, 3,4-fulleropyrrolidine-2spiro-4´-(2´,2´,6´,6´-tetramethylpiperidine-1´-oxyl (1). The synthesis and characterizations of MOF-177, MIL-53, 1 and their corresponding host-guest complex were provided in the experiment section in ESI (Figure S1-7).…”

“…It can be seen clearly from Figure 2a that around the diffraction angle of 6° emerged a bilateral peak in 1@MOF-177 compared with the as-synthesized MOF-177(as), corresponding to a lattice distance of about 14 Å, which can be ascribed to the crystal lattice perturbation caused by the incarceration of 1 into the pores of MOF-177. 10,11 Whereas in the case of 1@MIL-53, the XRD peak intensity of the first two reflexes (2θ = 8.59, 10.04, respectively) decreased remarkably after a swarm of guest molecules were in residence, which was attributed to the probably saturated pore filling of MIL-53 by 1. 12,15 Though the XRD pattern in the small-angle region is susceptible to guest disturbance, the distinctive changes in 1@MOF-177 and 1@MIL-53 provide a first indication that the guest molecule 1 was mono-dispersed in the pores of MOF-177, but aggregated in the 1D channels of MIL-53 in consideration of the strong π-π interaction between the fullerene cages, as shown in Figure 1d and e. Along with the change of XRD patterns, the sample color deepened after the host-guest complexes formed as shown in the insets of Figure 2, further confirming the inclusion of 1 in the apertures of MOF-177 and MIL-53.…”

Novel fluorescent porous hyperbranched aromatic polyamide containing 1,3,5‐triphenylbenzene moieties: Synthesis and characterization

“…1,3,5‐Tri(4‐carboxyl phenyl) benzene (H 3 BTB) has three carboxyl groups in its molecular structure which is a potential B 3 monomer to construct hyperbranched polymers. Although until now, H 3 BTB is widely used to synthesize porous coordination polymers . To the best of the author's knowledge, there have no report concerning the synthesis of hyperbranched polymers using H 3 BTB as a reactive monomer.…”