Efficient Preparation of Monoadducts of [60]Fullerene and Anthracenes by Solution Chemistry and Their Thermolytic Decomposition in the Solid State

Abstract

The efficient preparation of monoadducts of [60]fullerene and seven anthracenes (anthracene, 1-methylanthracene, 2-methylanthracene, 9-methylanthracene, 9,10-dimethylanthracene, 2,3,6,7-tetramethylanthracene, and 2,6-di-tert-butylanthracene) by cycloaddition in solution is described. The seven mono-adducts of [60]fullerene and the anthracenes were characterized spectroscopically and were obtained in good yields as crystalline solids. The monoadducts of [60]fullerene and anthracene, 1-methylanthracene, 2-methylanthracene and 9,10-dimethylanthracene crystallized directly from the reaction mixture. The thermolytic decomposition at 180 degrees C of the crystalline monoadducts of [60]fullerene and anthracene, 1-methylanthracene, 9-methylanthracene and 9,10-dimethylanthracene all gave rise to the specific formation of a roughly 1:1 mixture of [60]fullerene and the corresponding antipodal bisadducts ("trans-1"-bisadducts) of [60]fullerene and the anthracenes. In contrast, the crystalline monoadducts of [60]fullerene and the anthracene derivatives 2-methylanthracene, 2,3,6,7-tetramethylanthracene and 2,6-di-tert-butylanthracene all decomposed to [60]fullerene and anthracenes (without detectable formation of bisadducts) upon heating in the solid state to temperatures of 180 to 240 degrees C. The formation of the antipodal bisadducts from thermolytic decomposition of crystalline samples of the monoadducts was rationalized by topochemical control.

Molecular self-healing mechanisms between C60-fullerene and anthracene unveiled by Raman and two-dimensional correlation spectroscopy

“…27,53,54 We did not isolate every single isomer, because the stereochemistry is not important for the self-healing process. 27,53,54 We did not isolate every single isomer, because the stereochemistry is not important for the self-healing process.…”

Supramolecular control of electronic properties in aromatic materials

“…To circumvent the difficulties associated with the preparation of functional monolayers of extended π-aromatic structures, we explored an approach that is intermediate between the self-organized SAMs of thiols on gold and the covalent grafting of silanes on SiO 2 [26]. It relies on the reversible covalent cycloaddition reaction between fullerene and anthracene [27]. This [4 + 2] Diels-Alder reaction is reversible at room temperature, and does not require or release external reagents.…”

Cycloadditions

“…An even more pronounced retro-Diels-Alder reaction occurs by using 1,3-diphenylisobenzofuran (DPIF), 9-methylanthracene or 9,10-dimethylanthracene as dienes [8,[10][11][12]. The monoadduct of DPIF cannot be isolated from the reaction mixture, while the monoadduct of the 9-methyl-or 9,10-dimethyl-derivatives of anthracene can be isolated at temperatures lower than room temperature [10].…”

“…Thermal treatment of solid C 60 (anthracene) was successfully employed for the selective synthesis of the trans-1-C 60 (anthracene) 2 bisadduct by the disproportionation of two C 60 (anthracene) molecules into C 60 (anthracene) 2 and C 60 [10].…”

“…Anthracene as well as its derivatives and also higher acenes can be added to C 60 either in solution by refluxing in toluene or dichlorobenzene [10,17,18] or with solid-state techniques [19]. Anthracene addition may be enhanced by irradiation with light [20].…”