Yanbang Li

N-Fluorobenzenesulfonimide Based Functionalization of C60

The reaction of N-fluorobenzenesulfonimide (NFSI) with C60 and exploration of the product as a precursor for various 1,2- and 1,4-bisfullerene adducts are reported. NFSI is also found to act as an oxidant in the reaction of C60 with cyclic amines such as pyrrolidine yielding tetraaminoaziridino adducts.

Preparation of Azafullerene C59NR5 and Fullerene Derivative C60NAr5 with a Pyridine Moiety on the Cage Skeleton

[60]Fullerene hexaadducts C60R5Cl (R = OMe or Ar) reacted with hydroxylamine to form C60R5(NHOH) with the hydroxylamino group attached on the central pentagon as in the starting material. Further reactions including treatment with PCl5 and basic alumina led to the insertion of the nitrogen atom into the fullerene cage skeleton and decarbonylation to form azafullerenes C59N(H)(OMe)4 and C59N(OMe)5. The fullerene derivatives C59N(CO)R5 and C60NAr5 with a pyridinone and a pyridine moiety on the cage skeleton, respectively, were also synthesized starting from the hydroxylamine adducts.

Selective Addition of Secondary Amines to C60: Formation of Penta- and Hexaamino[60]fullerenes

Secondary amines are well-known to add to [60]fullerene to form the tetraamino epoxy adduct C60(O)(NR1R2)4 under both photolysis and thermal conditions in the presence of oxygen. We have now found that pentaamino hydroxyl adduct C60(OH)(NR1R2)5 and hexaamino adduct C60(NR1R2)6 can be formed as the major products in the dark in the presence of oxygen. Key steps of the reaction mechanism probably involve repeated oxygen oxidation of the radical ion pair between fullerene and amines.

Fullerene-Based Macro-Heterocycle Prepared through Selective Incorporation of Three N and Two O Atoms into C60

A 14-membered heterocycle is created on the C60 cage skeleton through a multistep procedure. Key steps involve repeated PCl5 -induced hydroxylamino N-O bond cleavage leading to insertion of nitrogen atoms, and also piperidine-induced peroxo O-O bond cleavage leading to insertion of oxygen atoms. The hetero atoms form one pyrrole, two pyran, and one diazepine rings in conjunction with the C60 skeleton carbon atoms. The fullerene-based macrocycle showed unique reactivities towards fluoride ion and copper salts.

Synthesis of C70-Based Fluorophores through Sequential Functionalization to Form Isomerically Pure Multiadducts

Selective addition to the C70 cage divides its π-conjugated system into various smaller π-conjugated systems with enhanced fluorescent properties. Key reactions include chlorination, methoxylation, ozonation, and Bingel or Bingel-Hirsch reactions. The maximum emission wavelength of the C70 multiadducts ranges from 450 to 655 nm. Among the C70 multiadducts, C70 (OMe)8 (C(COOEt)2 )3 showed the highest quantum yield (ΦF =0.18) and the largest Δ[λmax (emission)- λmax (absorption)] (402 nm), with maximum emission at 655 nm.

Controlled Synthesis of Nitrogen-Doped Graphene on Ruthenium from Azafullerene

The controlled synthesis of high-quality nitrogen (N) doped single layer graphene on the Ru(0001) surface has been achieved using the N-containing sole precursor azafullerence (C59NH). The synthesis process and doping properties have been investigated on the atomic scale by combining scanning tunneling microscopy and X-ray photoelectron spectroscopy measurements. We find for the first time that the concentration of N-related defects on the N-doped graphene/Ru(0001) surface is tunable by adjusting the dosage of sole precursor and the number of growth cycles. Two primary types of N-related defects have been observed. The predominant bonding configuration of N atoms in the obtained graphene layer is pyridinic N. Our findings indicate that the synthesis from heteroatom-containing sole precursors is a very promising approach for the preparation of doped graphene materials with controlled doping properties.

[60]Fullerene-based Macrocycle Ligands

Macrocycle ligands have three or more donor sites. Selective replacement of skeleton carbon atoms by heteroatoms and vacancies in C60 could lead to various macrocycle ligands with a cage-shaped backbone. Theoretical calculations indicate that such C60 -based macrocycle ligands are as stable as C60 thermodynamically according to their similar HOMO-LUMO gaps. The synthesis of these ligands is a challenging task. Nevertheless important progresses have been reported. This concept article focuses on the structures of possible C60 -based macrocycle ligands and related synthetic results.

Synthesis of homoazafullerene [C59N(CH2)]R and azahomoazafullerene [C59N(NH)]R

The selective insertion of a CH2 or NH group at the 5,6-junction on the C59N skeleton is achieved through the PCl5 induced reaction of a CH2OH or NHOH group on the cage to form [C59N(CH2)]R or [C59N(NH)]R, respectively. Spectroscopic data and single crystal X-ray diffraction structure analysis confirmed the 5,6-open homoazafullerene structure.