Rigid Tether Directed Regioselective Synthesis and Crystallographic Characterization of Labile 1,2,3,4‐Bis(triazolino)[60]fullerene and Its Thermolized Derivatives

Abstract

Labile bis-triazoline adducts of C60 are supposed to be the precursors of bis-azafulleroids, but the formation mechanism is still unclear because of the incomplete isolation of the thermolized products and the lack of X-ray structures. A rigid-tethered reagent 1,2-bis(azidomethyl)benzene (1) was used to regioselectively synthesize the labile 1,2,3,4-bis(triazolino)[60]-fullerene (2), the structure of which was determined by single-crystal X-ray crystallography. Further thermolysis of 2 produces four products (3 a-3 d), which were all characterized by X-ray crystallography. Although 3 a and 3 b have traditional bis-azafulleroid structures, as proposed previously, 3 c and 3 d show unprecedented structures with either the coexistence of [5,6]-open and [6,6]-closed patterns or an oxidized structure with an 11-membered ring on the cage. A thermolysis mechanism is proposed to clarify long-term confusion about the transformation process from bis-triazoline adducts to bis-azafulleroids of C60 .

Successively Regioselective Electrosynthesis and Electron Transport Property of Stable Multiply Functionalized [60]Fullerene Derivatives

“…All new products 1b, 1c, 2a-c, and 3a-c were fully characterized by MALDI-TOF HRMS, 1 H NMR, 13 C NMR, FT-IR, and UV-Vis spectroscopies. Particularly, the two doublets around 6 ppm with a coupling constant of 2.3 Hz in the 1 H NMR spectra of products 3a-c indicated that they contained two fullerenyl protons in 1,4arrangement [44].…”

“…Only one isomeric monocycloadduct is usually formed, up to 8 regioisomeric biscycloadducts have been isolated from cycloaddition reactions of C 60 [8]. On the other hand, the regioisomers of tetrafunctionalized C 60 derivatives reported most commonly are 1,2,3,4-isomers (A) [9][10][11][12][13][14], 1,4,11,15-isomers (B) [15][16][17][18], 1,2,4,15-isomers (C) [19][20][21][22][23], and 1,2,3,16-isomers (D) [24][25][26][27][28][29], while for the hexafunctionalized C 60 derivatives, the most frequently encountered regioisomers are 1,2,3,4,5,6-isomers (E) [30][31][32] and 1,2,4,11,15,30-isomers (F) [15][16][17][18][33][34][35] (Figure 1). Although the elegant templated multifunctionalizations of fullerenes have been devised to realize high regioselectivity [8,36], the regiocontrol on the formation of a specific isomer of biscycloadducts and multicycloadducts is still a daunting task.…”

“…In our recent work [38], we disclosed the synthesis of tetra-and hexafunctionalized [60]fullerene derivatives with unprecedented addition patterns from the reaction of 1a 2with 1,2-bis(bromomethyl)benzene. Even though we could capture the intermediate leading to the cyclized 1,2,4,17-adduct, the instability of this unique cyclized product precluded its characterization by 13 C NMR and single-crystal X-ray analysis. Bearing the aforementioned different reactivity of the same dianionic species toward alkylating and acylating reagents and instability of the previously obtained tetrafunctionalized product in mind, our continuous efforts in electrochemical functionalization of fullerene derivatives [25,28,29,[38][39][40][41] stimulated us to investigate the reaction of the dianionic [60]fulleroindolines 1a-c 2-with phthaloyl chloride in order to contrast their reactivity behavior and to see if the unprecedented tetrafunctionalized cis-3 ′ isomers (type G) and "S"-shaped hexafunctionalized products (type H) bearing two acyl groups can be generated in the present case [42].…”

Fullerene Stabilizer 4,11,15,30-Tetraarylamino Fullerenoarylaziridine: Regioselective Synthesis, Crystallographic Characterization Derivatives, and Potential Application as Propellant Stabilizer

“…Although the complete fullerene molecular structure is relatively stable with strong capacity for absorbing free radicals, the rate of “capture” to free radicals is low. − Functional fullerene derivative can substantially increase the rate of “capture” to free radicals, which ascribed to the modification of functional groups to destroy the conjugated structure of fullerenes. − C 60 Cl 6 is a widespread precursor for the synthesis of highly functionalized fullerene derivatives. − Many different nucleophiles can replace the chlorine atoms in C 60 Cl 6 to form multifunctional fullerene derivatives. − In this study, C 60 Cl 6 as a precursor was applied to synthesize multifunctional fullerene derivatives via the reaction with aromatic amines (Scheme ), and its possibility as a propellant stabilizer was studied. We first explored the reactions of C 60 Cl 6 and aniline 1a .…”

Quantitative Mono‐Formation and Crystallographic Characterization of Pyrazole‐ and Pyrrole‐Ring Fused Derivatives of C60

“…One of the main objective of fullerene chemistry is the production of well‐defined, stable and characterizable adducts , , . However, various reactions on C 60 usually lead to a complex mixture containing mono‐adducts together with several bis‐ or multi‐adduct isomers, which possess different molecular structures but similar chromatographic properties, making the subsequent separations rather tricky . In fullerene chemistry, accordingly, it is desirable to develop highly regioselective synthetic methods to get merely mono‐adducts for sake of further structural characterizations and applications as well.…”