Photoreactions of Sc3N@C80 with Disilirane, Silirane, and Digermirane: A Photochemical Method to Separate Ih and D5h Isomers

Abstract

Under photoirradiation, Sc3N@Ih-C80 reacted readily with disilirane 1, silirane 4, and digermirane 7 to afford the corresponding 1:1 adducts, whereas Sc3N@D5h-C80 was recovered without producing those adducts. Based on these results, we described a novel method for the exclusive separation of Ih and D5h isomers of Sc3N@C80. The method includes three procedures: selective derivatization of Sc3N@Ih-C80 using 1, 4, and 7, facile HPLC separation of pristine Sc3N@D5h-C80 and Sc3N@Ih-C80 derivatives, and thermolysis of Sc3N@Ih-C80 derivatives to collect pristine Sc3N@Ih-C80. In addition, laser flash photolysis experiments were conducted to elucidate the reaction mechanism. Decay of the transient absorption of 3Sc3N@Ih-C80* was observed to be enhanced in the presence of 1, indicating the quenching process. When Sc3N@D5h-C80 was used, the transient absorption was much less intensive. Therefore, the quenching of 3Sc3N@D5h-C80* by 1 could not be confirmed. Furthermore, we applied time-dependent density functional theory (TD-DFT) calculations of the photoexcited states of Sc3N@C80 to obtain insights into the reaction mechanism.

Recent Progress on the Functionalization of Endohedral Metallofullerenes

“…Very recently, a novel method for the exclusive separation of I h and D 5h isomers of Sc 3 N@C 80 was proposed based on the different reactivity of photoreactions of Sc 3 N@I h -C 80 and Sc 3 N@D 5h -C 80 with disilirane, silirane, and digermirane [43]. Specifically, under the same condition, Sc 3 N@I h -C 80 reacted readily with them to afford the corresponding 1:1 adducts, whereas Sc 3 N@D 5h -C 80 was recovered without any adducts [43].…”

“…Very recently, a novel method for the exclusive separation of I h and D 5h isomers of Sc 3 N@C 80 was proposed based on the different reactivity of photoreactions of Sc 3 N@I h -C 80 and Sc 3 N@D 5h -C 80 with disilirane, silirane, and digermirane [43]. Specifically, under the same condition, Sc 3 N@I h -C 80 reacted readily with them to afford the corresponding 1:1 adducts, whereas Sc 3 N@D 5h -C 80 was recovered without any adducts [43]. According to these results, the separation solution was put forward and involved three steps: selective derivatization of Sc 3 N@I h -C 80 with disilirane, silirane, and digermirane, facile high performance liquid chromatography (HPLC) separation of pristine Sc 3 N@I h -C 80 and Sc 3 N@D 5h -C 80 derivatives, and thermolysis of corresponding derivatives to recovery pristine Sc 3 N@I h -C 80 [43].…”

“…Specifically, under the same condition, Sc 3 N@I h -C 80 reacted readily with them to afford the corresponding 1:1 adducts, whereas Sc 3 N@D 5h -C 80 was recovered without any adducts [43]. According to these results, the separation solution was put forward and involved three steps: selective derivatization of Sc 3 N@I h -C 80 with disilirane, silirane, and digermirane, facile high performance liquid chromatography (HPLC) separation of pristine Sc 3 N@I h -C 80 and Sc 3 N@D 5h -C 80 derivatives, and thermolysis of corresponding derivatives to recovery pristine Sc 3 N@I h -C 80 [43]. Furthermore, the reaction mechanism has been studied by laser flash photolysis experiments [43].…”

“…According to these results, the separation solution was put forward and involved three steps: selective derivatization of Sc 3 N@I h -C 80 with disilirane, silirane, and digermirane, facile high performance liquid chromatography (HPLC) separation of pristine Sc 3 N@I h -C 80 and Sc 3 N@D 5h -C 80 derivatives, and thermolysis of corresponding derivatives to recovery pristine Sc 3 N@I h -C 80 [43]. Furthermore, the reaction mechanism has been studied by laser flash photolysis experiments [43]. Decay of the transient absorption of 3 Sc 3 N@I h -C 80 * was observed to be enhanced in the presence of disilirane, indicating the quenching process; however, the transient absorption of 3 Sc 3 N@D 5h -C 80 * was much less intensive, which could not confirm the quenching of 3 Sc 3 N@D 5h -C 80 * by disilirane [43].…”

“…Furthermore, the reaction mechanism has been studied by laser flash photolysis experiments [43]. Decay of the transient absorption of 3 Sc 3 N@I h -C 80 * was observed to be enhanced in the presence of disilirane, indicating the quenching process; however, the transient absorption of 3 Sc 3 N@D 5h -C 80 * was much less intensive, which could not confirm the quenching of 3 Sc 3 N@D 5h -C 80 * by disilirane [43]. Finally, based on the time-dependent density functional theory (TD-DFT) calculations, the poor electron acceptor property of 3 Sc 3 N@D 5h -C 80 * might decrease the photochemical reactivity toward disilirane, silirane, and digermirane compared to 3 Sc 3 N@I h -C 80 * [43].…”