Heterospin frustration in a metal-fullerene-bonded semiconductive antiferromagnet

Dinuclear iridium complexes ligated by lithium-ion endohedral fullerene Li+@C60

The diiridium complexes of lithium-ion endohedral fullerene Li+@C60 were synthesised in high yields. X-ray crystallography revealed the η2:η2-coordination of Li+@C60 and the disorder of the Li+ ion over two sites close to the coordinated carbons. 13C NMR study suggested the presence of dynamic behaviour via haptotropic rearrangements. UV/Vis and CV characteristics were also investigated experimentally and theoretically.

Diamagnetic Carrier-Doping-Induced Continuous Electronic and Magnetic Crossover in One-Dimensional Coordination Polymers

The potential to introduce tunable electrical conductivity and molecular magnetism through carrier doping in metal-organic coordination polymers is particularly promising for nanoelectronics applications. Precise control of the doping level is essential for determining the electronic and magnetic properties. In this study, we present a series of one-dimensional coordination polymers, {(HNEt3)0.5[CuxCo(1-x)(L)]}n (HNEt3 = triethylammonium, L = 1,2,4,5-tetrakis(methanesulfonamido)benzene), doped with diamagnetic Cu1+ carriers. Through comprehensive characterization of the structural, optical, and magnetic properties, we observed continuous electronic and magnetic crossover as the doping level was gradually increased. When x < 0.5, the doped compounds exhibit ferromagnetic insulating behavior with very high energy barriers (Ueff up to 560 K) and excellent slow relaxation of magnetization. At x = 0.5, {(HNEt3)0.5[Cu0.5Co0.5(L)]}n functions as a paramagnetic semiconductor at high temperatures and a single-molecule magnet at low temperatures. When x > 0.5, the doped compounds act as diluted antiferromagnetic semiconductors with narrow band gaps (Ea = 0.2 eV). The emergence of such rich electronic and magnetic crossovers is ascribed to the cooperation of the strong electron-donating ability of the ligand and the pronounced crystal-field effects. Our findings indicate that one-dimensional (1D) coordination polymers are promising for the design of novel low-dimensional magnetic semiconductors.

Electronic Structure, Aromaticity, and Magnetism of Minimum-Sized Regular Dodecahedral Endohedral Metallofullerenes Encapsulating Rare Earth Atoms

A series of minimally sized regular dodecahedron-embedded metallofullerene REC20 clusters (RE = Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, and Gd) as basic units of nanoassembled materials with tunable magnetism and UV sensitivity have been explored using density functional theory (DFT). The contribution of the 4f orbital of the rare earth atom at the center of the C20 cage to the frontier molecular orbital of REC20 gives the REC20 cluster additional stability. The AdNDP orbitals of the four REC20 superatoms that conform to the spherical jellium model indicate that through natural population analysis and spin density diagrams, we observe a monotonic increase in the magnetic moment from Ce to Gd. This is attributed to the increased number of unpaired electrons in the 4f orbitals of lanthanide rare earth atoms. The UV-visible spectrum of REC20 clusters shows strong absorption in the mid-UV and near-UV bands. REC20 clusters encapsulating lanthanide rare earth atoms stand out for their tunable magnetism, UV sensitivity, and stability, making them potential new self-assembly materials.

Sequential click modification of a lithium-ion endohedral fullerene connecting small molecules through a dieneazide linker

A versatile method for the chemical modification of a lithium-ion endohedral fullerene (Li⁺@C₆₀) to connect various small molecules is described. The designed dieneazide linker enables the facile connection of Li⁺@C₆₀ with small molecules bearing a terminal alkyne via Huisgen annulation and a subsequent Diels-Alder reaction. This strategy significantly expands the diversity of small molecules to be attached by Li⁺@C₆₀.

A 1D Mixed-Valence Cuprofullerene Pyrazolate Polymer as a Semiconductor Material

Polymeric {Cu₆[(μ₃-η²:η²:η²)₂-C₆₀](FPz)₆Cl·3C₆H₅Cl}_∞ [FPz = 4-(trifluoromethyl)pyrazolate], synthesized solvothermally with chlorobenzene as the solvent, is a doubly-connecting trans bis-adduct hexanuclear cuprofullerene that has copper in mixed valence. The compound is an example of a metallofullerene having semiconductivity character.

Regioisomeric core-shell cuprofullerene C60@Cu24

The controlled synthesis of high-nuclear regioisomeric core-shell exohedral metallofullerenes (ExMFs) is challenging. Herein, we demonstrated the synthesis of regioisomeric core-shell cuprofullerene C₆₀@Cu^I₂₄ and its 3-D coordination polymer using heteroleptic ligands, realizing high-nuclear regioisomeric ExMFs and a polymeric ExMF structure.