Development of the method of alkylation of C_<60> by way of alkylfullerenyl cation

烷基富勒烯基阳离子烷基化C_<60>方法的开发

• 批准号: 12650810
• 负责人: KITAGAWA Toshikazu
• 金额: $ 2.18万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650810/
• 关键词: fullerene; carbocation; alkylation; electrophilic addition; fullerenol; ^<13>C NMR; 分子内配位

We found that fullerene C_<60> undergoes electrophilic addition when treated with a large excess of AlCl_3 in chloroalkanes (RCl), giving adducts RC_<60>-Cl in good yields. The intermediate, alkylfullerenyl cations (RC_<60>^+), could be generated as long-likved ions by dissolving fullerenols (RC_<60>OH) in strong acids such as CF_3SO_3H and H_2SO_4. These cations were observed by NMR and vis/NIR spectra as long-lived species. The ^<13>C NMR spectra indicated that the positive charge is located mainly on C-2, and the structure has C_s symmetry. The chemical shift of the cationic center (175-180 ppm) suggested a weak coordination of chlorine atom(s) in the group R to the cationic center.Cations RC_<60>^+ could be also generated in situ by the abstraction of a chloride ion from chlorides RC_<60-> Cl with AlCl_3. When the reactions were carried out in anisole, nucleophilic addition of a solvent molecule to RC_<60>^+ occurred, giving the corresponding adducts RC_<60>-C_6H_4OCH_3-p. The chloride ion can be also abstracted by AgBF_4. With this reagent the reaction could be carried out in alcohols (R'OH), giving the corresponding ethers RC_<60>-OR' in good yiels.Chlorides RC_<60>-Cl (R=chloroalkyl) were found to undergo solvolysis in anisole-trifluoroethanol mixed solvent (1:9 v/v) to give S_N1 reaction products, RC_<60>-Y(Y=p-anisyl and trifluoroethoxy). The free energies of activation (24-25 kcal/mol at 25℃) were only slightly lower than that for the tert-butyl chloride, indicating that cations RC_<60>^+ have stabilities close to that of the tert-butyl cation.The pK_R^+ values of cations RC_<60>^+ were also determined from the equilibrium constants for the ionization of the corresponding fullerenols. The obtained values are comparable to the pK_R+ of the tert-butyl cation. Thsi result also support the similarity in stability between RC_<60>^+ and the tert-butyl cation.

我们发现富勒烯C_1<60>在氯代烷烃（RCl）中与过量的AlCl_3发生亲电加成反应，得到了较好的加成产物<60>RC_1-Cl。富勒<60>烯醇（RC_<60>OH）在强酸（如CF_3SO_3H和H_2SO_4）中溶解，可生成长寿命的烷基富勒烯阳离子（RC_ ^+）。通过NMR和维斯/近红外光谱观察到这些阳离子作为长寿命物种。~ 1C <13>NMR谱表明，正电荷主要位于C-2位，结构具有C_s对称性。阳离子中心的化学位移（175-180 ppm）表明R基团中的氯原子与阳离子中心弱配位，<60>也可通过AlCl_3从氯化物RC_ Cl中夺取氯离子原位生成阳离子RC_ ^+<60->。当反应在苯甲醚中进行时，溶剂分子与RC ^+发生亲核加成<60>，得到相应的加合物RC<60>-C_6H_4OCH_3-p。用此试剂在醇（R ′ OH）中进行反应，得到相应的醚类化合物RC_<60>-OR ′，氯化物RC_<60>-Cl（R=氯代烷基）在苯甲醚-三氟乙醇（1：9 v/v）混合溶剂中发生溶剂分解，得到S_N1反应产物RC_<60>-Y（Y=对苯甲醚和三氟乙氧基）。活化自由能（24-25 kcal/mol，25℃）仅略低于叔丁基氯的活化自由能，表明阳离子RC <60>^+具有与叔丁基氯相近的稳定性，阳离子RC ^+的pK_R^+值<60>也由相应富勒醇的电离平衡常数确定。所得值与叔丁基阳离子的pK_R ~+相当。这一结果也支持了RC_ ^+与叔丁基阳离子在稳定性上的相似性<60>。

项目成果

北川敏一, 李 洋洙, 花村政暁, 坂本晴美, 紺野博文, 竹内賢一, 小松紘一: "Nucleophilic Substitution of Alkylchlorodihydro [60] fullerenes : Thermodynamic Stabilities of Alkylated C_<60> Cation Intermediates"Chemical Communications. 3062-3063 (2002)

Toshikazu Kitakawa、Yosu Lee、Masaaki Hanamura、Harumi Sakamoto、Hirofumi Konno、Kenichi Takeuchi、Koichi Komatsu：“烷基氯二氢[60]富勒烯的亲核取代：烷基化 C_<60> 阳离子中间体的热力学稳定性”化学通讯 3062-3063（2002 年）。 ）

北川敏一, 田中 徹, 村北英之, 西川敦准, 竹内賢一: "Reaction of Cyclopropenylium Ion with the tert-Butyl-C_<60>-anion : Carbocation-Carbanion Coordination vs Salt Formation"Tetrahedron. Vol.57. 3537-3547 (2001)

Toshikazu Kitakawa、Toru Tanaka、Hideyuki Murakita、Atsushi Nishikawa、Kenichi Takeuchi：“环丙烯离子与叔丁基-C_<60>-阴离子的反应：碳正离子-碳负离子配位与盐形成”四面体第 3537-3547 卷。 (2001)

北川敏一, 竹内賢一: "Monofunctionalized C_<60> Ions : Thier Generation, Stability, and Reactions"Bulletin of the Chemical Society of Japan. Vol.74. 785-800 (2001)

Toshikazu Kitakawa、Kenichi Takeuchi：“单官能化 C_<60> 离子：其生成、稳定性和反应”日本化学会通报第 74 卷（2001 年）。

Toshikazu Kitagawa, Yangsoo Lee, Masaaki Hanamura, Harumi Sakamoto, Hirofumi Konno, Ken'ichi Takeuchi and Koichi Komatsu: "Nucleophilic Substitution of Alkylchlorodihydro [60] fullerenes : Thermodynamic Stabilities of Alkylated C_<60> Cation Intermediates

Toshikazu Kitakawa、Yangsoo Lee、Masaaki Hanamura、Harumi Sakamoto、Hirofumi Konno、Kenichi Takeuchi 和 Koichi Komatsu：“烷基氯二氢 [60] 富勒烯的亲核取代：烷基化 C_<60> 阳离子中间体的热力学稳定性

Toshikazu Kitagawa, Toru Tanaka, Hideyuki Murakita, Atsunori Nishikawa, and Ken'ichi Takeuchi: "Reaction of Cyclopropenylium Ions with the tert-Butyl-C_<60> Anion : Carbocation-Carbanion Coordination vs Salt Formation"Tetrahedon. 57. 3537-3547 (2001)

Toshikazu Kitakawa、Toru Tanaka、Hideyuki Murakita、Atsunori Nishikawa 和 Kenichi Takeuchi：“环丙烯离子与叔丁基-C_<60> 阴离子的反应：碳正离子-碳负离子配位与盐形成”四面体。