【作者】 邵倩芬； 陈健； 吴泰琉； 蔡瑞芳； 黄祖恩；

【Author】 Shao Qian-fen~1 Chen Jian~2 Wu Tai-lu~1 Cai Rui-Fang~2 Huang Zu-en~2 ~1Research Center of Measurement,Fudan University Shanghai 200433 Department of Chemistry,Fudan University,Shanghai 200433

【机构】 复旦大学分析测试中心； 复旦大学化学系上海； 复旦大学化学系；

【摘要】 <正>人们在室温下检测[C₆₀]^-的电子自旋共振谱时,发现在特征的宽信号上面叠加了一个尖信号（英文为 spike）,为此很多人作了种种猜测。而我们在室温下,对 KC₆₀作¹³C 核磁测试时,发现在谱线底部,总存在着一个“小肩膀”（见图1）．后来在对 KC₆₀（THF）_x（0＜X＜1）作¹³C 核磁测试时,发现存在二条不同特征的¹³C 谱线,即它们的线宽、化学位移及自旋 -晶格弛豫时间 T₁各不相同,见图2．经变温¹³C NMR 波谱学的测试,我们认为,由于 THF 的引入,K⁺离子改变了[C₆₀]^-的电子态,当 K⁺离子对[C₆₀]^-的影响较小时,基态是²A 态,这与对自由的[C₆₀]^-离子的从头算（ab inito）相一致；当[C₆₀]^-离子受到 K⁺离子强烈扰动时, 排序（ordering）发生了颠倒,这时²E 态更为稳定．更多还原

【Abstract】 The ESR spectra of C^-₆₀contain a characteristic broad signal at the room temperature. In addition a narrow sharp signal（so--called spike）^[1]is found superimposed on the broad signal in many cases.Several proposals have been put forward to explain the origin of this spike.Meantime we performed ¹³C NMR experiment on KC₆₀（THF）and found that there is always a small“shoulder”in the bottom of the spectrum（see Fig.1）.Furthermore we performed ¹³C NMR experiment in KC₆₀（THF）_x（0＜X＜1）and found that there are different properties e.g.spectrum width,chemical shift and spin-lattice relaxation time T₁.for two peaks in the spectrum（see Fig.2）.Through the vertification of ³C NMR spectroscopy,we have concluded that solvating K⁺ ion by THF can change electronic states of C^-₆₀ion.When C^-₆₀is less affected by K⁺ ion,the ground is a ²A state,which is in good agreement with the ab inito calculation for the free C^-₆₀ion.When C^-₆₀is perturbed by K⁺ ion,However,the ordering is inverted,leading to the more stable ²E state.更多还原