Molecular Spectroscopic Study of Metallofullerenes

电子自旋共振（ESR）谱是表征内嵌金属富勒烯的有力手段。本文介绍了几个金属富勒烯的ESR测量实例。除了常规的cw-ESR技术外，脉冲ESR技术发展了对金属富勒烯性质的进一步研究，大量获得了各种镧系金属富勒烯[1-3]。其中Gd原子的电子结构被描述为4f^75d^16s^2，并预期基态高自旋态。我们<82>用X波段和W波段ESR谱仪测定了Gd@C_3。X-带ESR谱表现出与具有大精细结构的高自旋系统相对应的复杂模式。由于零场分裂参数D和E较大，导致了非对称的光谱特性，使我们无法进行简单的光谱模拟。为了简化Gd@C_的谱，进行了W带ESR测量<82>。我介绍 ...更多信息 顺<82>磁性金属富勒烯是一种很好的分子磁体的结构单元。用更大的π共轭分子包层包裹金属富勒烯是非常有趣的，这可能导致超分子磁体以3D方式延伸。Tashiro等人合成了一种环状金属卟啉二聚体[4]，并报道了在苯溶液中，<-1>锌卟啉二聚体与C_2形成的包<60>合物的缔合常数为6.7 × 10^5M ^。用脉冲ESR方法研究了金属卟啉环状二聚体与金属富勒烯包合物的电子自旋态。用脉冲ESR章动测量方法，获得了铜卟啉与La@C_2环状二聚体S=3/2耦合自旋态的直接实验证据<82>。根据卟啉和富勒烯上金属的结合，预计包合物的自旋状态会有很大的变化。少

Electron spin resonance (ESR) spectroscopy has been a powerful technique for the characterization endohedral metallofullerenes. Several examples of the ESR measurement for metallofullerenes are introduced in my talk. Besides a conventional cw-ESR technique, a pulsed-ESR technique developed the further investigation for the properties of metallofullerenes.Various metallofullerenes of lanthanide metals were abundantly obtained [1-3]. Among them the electronic structure of Gd atom is described as 4f^75d^16s^2, and the ground high spin state is expected. We examined Gd@C_<82> by means of X- and W-band ESR spectrometers. The spectrum of X-band ESR exhibited a complex pattern corresponding to that for the high-spin system with large fine structure. The un-symmetric spectral feature was given because of the large zero-field splitting parameters D and E, and prevented us from an easy spectral simulation. The W-band ESR measurement was performed to simplify the spectrum of Gd@C_<82>. I present … More the result of the W-band ESR measurement and the discussion of the electronic structure of Gd@C_<82>.A paramagnetic metallofullerene is a nice building block for a molecular magnet. Wrapping of a metallofullerene with larger π-conjugated molecular envelopes is of great interest, which may lead to an extension of the super-molecular magnet in a 3D-fashion. Tashiro et al. have synthesized a cyclic dimmer of metalloporphyrin [4], and reported the big association constant of 6.7 x 10^5 M^<-1> for the inclusion complex of a cyclic dimmer of zinc porphyrin with C_<60> in benzene solution. The electron spin state of an inclusion complex of a cyclic dimmer of metalloporphyrin with metallofullerene was investigated by means of pulsed-ESR measurement. The direct experimental evidence of the coupled spin state of S=3/2 was obtained for the cyclic dimmer of copper-porphyrin with La@C_<82> by the nutation measurement of pulsed-ESR. A big variety would be expected for the spin state of the inclusion complex in terms of the combination of metals on a porphyrin and a fullerene. Less