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

Abstract

Metallofullerenes have a cage-shaped molecular structure and special properties derived from encapsulated metal atoms. Owing to the ball-like fullerene cage, it is still a challenge to manipulate the metallofullerene molecule and to control its properties. Herein, we use the molecular carbon nanoring of [12]cycloparaphenylene to hoop the C 80 -based metallofullerene Y 3 N@C 80 and azafullerene Y 2 @C 79 N, resulting in a stable supramolecular complex, induced molecule orientation, changed assembly behavior, and tunable spin state. These supramolecular complexes and their host−guest interactions were systematically characterized by DFT-calculations, spectroscopy, NMR, and electrochemical analysis. Scanning tunneling microscopy was employed to reveal that the metallofullerene guests dominate the assembly process on the Au(111) surface and the [12]CPP nanoring can change the weak van der Waals forces and influence self-assembly. Moreover, the electron spin in paramagnetic Y 2 @C 79 N was employed to percept the host−guest interaction, and it showed anisotropic spin−metal couplings due to its insufficient rotational averaging in a confined space of the nanoring. The special spin character of Y 2 @C 79 N⊂[12]CPP was also investigated in its solid state, and it exhibits the independent spin of Y 2 @C 79 N separated by a nanoring. This study provides a strategy to hoop the ball-like C 80 -based metallofullerenes and modulate their electronic and magnetic properties using a circular nanoring. Metal-induced orientation, self-assembly characters, and susceptible electron spin for these supramolecular complexes reveal a great significance in molecule science and nanotechnology.

A Long‐Lived Azafullerenyl Radical Stabilized by Supramolecular Shielding with a [10]Cycloparaphenylene

“…[22][23][24] These convex molecules have been explored for fullerene complexation and the study of photoinduced phenomena. [25][26][27][28][29][30][31] Our approach takes advantage of 1) the 1.4 nm cavity of [10]CPP, resembling the inner space of carbon nanotubes favoring p-p host-guest interactions,t oa ccommodate aC 59 NC radical (Figure 1a), 2) the diminished environmental exposure of the radical resulting from the favorable orientation of the CPPs close to the exposed radical, and 3) the well-established chemistry of C 59 NC,w hich prevents chemical addition to 1,4substituted phenylenes because of steric hindrance. [16,32] We show that supramolecular complexation of C 59 NC by a [10]CPP nanobelt effectively shields the unpaired electron and blocks dimerization, resulting in the stable formation of unprecedentedly long-lived azafullerenyl radical species.…”

A Metallofullertube of Ce2@C100 with a Carbon Nanotube Segment: Synthesis, Single‐Molecule Conductance and Supramolecular Assembly

“…Recently, we have reported Y 2 @C 79 N and Y 3 N@I h -C 80 could insert into the cavity of [12]CPP nanohoop due to the matchable size and strong π-π interactions between them. [24] [12]CPP is a curved πconjugated molecule, and it resembles the shortest structural unit of carbon nanotube with intriguingly photophysical properties. It should be noted that supramolecular assembly can bring about new optical, electronic, and magnetic properties.…”

Fullerene in Carbon Nanoring: A Saturn-Like Supramolecular Complex

“…The special spin character of Y2@C79N⊂ [12]CPP was also investigated in its solid state, and it exhibits the independent spin of Y2@C79N separated by a nanoring. [25] Then they found that when the Y2@C79N and [4]CHBC are combined, a new peak will appear, revealing a strong host-guest interaction. [26]…”