Interfullerene Electronic Interactions and Excited-State Dynamics in Fullerene Dumbbell Conjugates

Abstract

Several dumbbell conjugates featuring M3N@I h -C80 (M = Sc, Y) and C60 were prepared to systematically investigate interfullerene electronic interactions and excited state dynamics. From electrochemical investigations, we concluded that the redox potentials of our M3N@I h -C80 (M = Sc, Y) dumbbells depend largely on the interfullerene electronic interactions. Assisted by DFT calculation, the unique role of metal atoms was highlighted. Most importantly, ultrafast spectroscopy experiments revealed symmetry-breaking charge separation in Sc3N@C80-dumbbell to yield an unprecedented (Sc3N@C80)•+-(Sc3N@C80)•– charge separated state. This is, to the best of our knowledge, the first time that symmetry-breaking charge separation following photoexcitation is corroborated in a fullerene system. As such, our work shed light on the significance of interfullerene electronic interactions and their uniqueness for modulating excited state properties.

Recent advances in supramolecular fullerene chemistry

“…[122][123][124][125] the insertion of different metals or metal clusters. 144,145 For instance, Lu 3 NCC 80 , a typical structure within the trimetallic nitride template (TNT) family, has a lower oxidation potential than C 60 and exhibits high stability compared to other EMFs. This property makes it an ideal electron donor, and in 2019, Martin and coworkers used Lu 3 NCC 80 in combination with C 60 as an acceptor to construct an ''all-fullerene'' donor-acceptor system.…”

Rational Construction and Efficient Regulation of Stable and Long-Lived Charge-Separation State in Fullerene Materials

“…Jablonski diagrams and photophysical dynamics of (e) C 60 -dumbbell, (f) Y 3 N@C 80 -dumbbell, and (g) Sc 3 N@C 80 -dumbbell. (a–g) Reproduced with permission from ref . Copyright 2023 American Chemical Society.…”

“…Similarly, reducing the acceptors LUMO level also contributes to more stable CSs. Recently, we have designed a series of fullerene (C 60 ) and metallofullerene (Sc 3 N@C 80 , Y 3 N@C 80 ) dumbbell structures to systematically study the interfullerene electronic interactions and their impact on electron transfer . The research demonstrated that in C 60 dumbbell and Y 3 N@C 80 dumbbell molecules, large electrochemical gaps positioned CSs above the 1 LEs, thus preventing charge separation (Figure ).…”

“…Since their discovery in 1985, fullerenes have been extensively studied and developed in various fields in the last 40 years. These include biomedical science, energy conversion, catalytic chemistry, single-molecule devices, and electron spin research. − One of the most fascinating studies on fullerenes is their excited-state properties. ,, Owing to their high electron affinity, low reorganization energy, three-dimensional electron coupling effects, well-defined structure, molecular stability, and tunable energy levels, fullerenes are considered star acceptor molecules in photoelectric materials. ,, These properties of fullerenes facilitate stable and long-lived CSs. , …”

Synthesis and characterization of water-soluble C60–peptide conjugates

“…Since the seminal discovery in 1985 by Kroto, Smalley, Curl, and co-workers [ 1 ], fullerenes, specifically buckminsterfullerene C 60 , have intrigued the scientific community. The unique structure of fullerenes, characterized by a fully conjugated closed-cage structure, containing a mixture of hexagonal and pentagonal rings, have been recognized for the unique electronic [ 2 – 4 ], optical [ 5 – 6 ], and mechanical properties [ 7 – 8 ]. Despite the notable achievements in fullerene research and the potential applications in diverse fields, a significant obstacle remained for the use in biological studies: fullerenes are poorly soluble in polar solvents, including water and other water-miscible solvents [ 9 ].…”