Anisotropic Paramagnetic Properties of Metallofullerene Confined in a Metal–Organic Framework

Abstract

Paramagnetic metallofullerenes have a spherical molecular structure and stable unpaired spin protected by a fullerene cage and have potential applications in quantum information processing, etc. For endohedral azafullerene Y2@C79N, the N atom on the cage endows the molecule with unpaired spin and is proposed to induce the molecule orientation within the MOF pore via host–guest interaction. Angular-dependent EPR spectroscopy was employed on the Y2@C79N⊂MOF-177 complex to detect the anisotropic paramagnetic properties. These results experimentally confirmed the trend of molecule orientation of Y2@C79N within MOF-177 under certain conditions, which also induces the presence of several conformers of Y2@C79N. The additional EPR splittings in Y2@C79N⊂MOF-177 are proposed to originate from partially disordered molecules as well as the N-coupling of Y2@C79N upon implanting it into the MOF-177 pore. The N-defect on the fullerene cage of Y2@C79N is expected to be utilized as an anchor to build a three-dimensional spin array within MOF matrix.

Supramolecular Complexes of C80-Based Metallofullerenes with [12]Cycloparaphenylene Nanoring and Altered Property in a Confined Space

“…The agreement of simulated and experimental EPR spectra reveals the highly isolated Y 2 @C 79 N molecules without serious agglomeration. Moreover, the axisymmetric parameters in the Y 2 @C 79 N⊂[12]­CPP solid were also observed in the Y 2 @C 79 N⊂MOF-177 complex and Y 2 @C 80 (CH 2 Ph) derivative. ,, Generally, the EPR tensors reflect the structural characteristics of the spin molecule, and the low-symmetry molecule is often accompanied by irregular coupling parameters because of the low-symmetry lattice field. Here, the axisymmetric hyperfine couplings of Y 2 @C 79 N⊂[12]­CPP indicate that the Y 2 cluster coupled with unpaired spin in the Y 2 @C 79 N molecule has an orientation in the solid state rather than in random directions.…”

“…Scanning tunneling microscopy (STM) was employed to illustrate the molecular form and assembled behaviors of these supramolecular complexes on the Au(111) surface. Typically, endohedral azafullerene Y 2 @C 79 N, which has a defective carbon cage originating from the N substitution on the C 80 cage with susceptible electron spin, − will percept the confinement effect from the [12]­CPP nanoring. The N defect of Y 2 @C 79 N changes the molecule symmetry and polarizes the electron distributions, and it could greatly influence the host–guest structure.…”

Spectroscopy, microscopy, diffraction and scattering of archetypal MOFs: formation, metal sites in catalysis and thin films

“…rotational motions of pyridine on Al 3+ or Al-OH sites or the effects of adsorbates on the backbone. 122,123 This has been also successfully employed in different frameworks, [124][125][126] sometimes being able to discriminate between competing adsorbing molecules of very similar nature. 127 Thus, beyond the use of well-known basic probe molecules to study MOF acidity (e.g.…”

Molecular Fullerenes Encapsulated in Metal-Organic Frameworks

“…The incorporated Y2@C79N in MOF-177 show axisymmetric paramagnetic property, making it potential quantum bits for quantum information science and data storage. Later in 2018, Zhao and co-workers [64] further reported the orientation-related paramagnetic properties of Y2@C79N in MOF-177 by the angular-dependent EPR spectroscopy. The results showed that the partially oriented molecules of Y2@C79N in MOF-177 caused the orientation-related EPR splitting.…”