Konarev Dmitri V, Khasanov Salavat S, Kovalevsky Andrey Y, Saito Gunzi, Otsuka Akihiro, Lyubovskaya Rimma N
Division of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
Dalton Trans. 2006 Aug 14(30):3716-20. doi: 10.1039/b603685f. Epub 2006 May 4.
Single crystals of the ionic C60 complex with bis(benzene)chromium: {Cr(I)(C6H6)2(.+)}.(C60.-)).C6H4Cl2 (1) were obtained. The crystal structure of 1 shows the presence of monomeric C60.- radical anions at 250 K and the formation of single-bonded (C60-)2 dimers at 90 K. The dimerization is realized in two types of the C60.-) pairs with different interfullerene center-to-center distances of 10.052 and 10.279 A arranged in zigzag chains along the a-direction. As a result, two symmetrically independent (C60-)2 dimers found in 1 at 90 K have different environments, intercage C-C bond lengths and C60- center-to-center distances. Such differences should provide different thermal stability of these dimers and result in the appearance of two stages at the dimerization. Indeed, according to SQUID measurements, the magnetic moment of 1 decreases stepwise at the dimerization in two temperature ranges at 240-200 and 200-160 K.
得到了离子型C60与双（苯）铬配合物的单晶：{Cr(I)(C6H6)2(.+)}.(C60.-)).C6H4Cl2 (1)。1的晶体结构表明，在250 K时存在单体C60.-自由基阴离子，在90 K时形成单键连接的(C60-)2二聚体。二聚化通过两种类型的C60.-)对实现，它们具有不同的富勒烯中心到中心距离，分别为10.052和10.279 Å，沿a方向排列成锯齿链。因此，在90 K时在1中发现的两个对称独立的(C60-)2二聚体具有不同的环境、笼间C-C键长和C60-中心到中心距离。这些差异应该会导致这些二聚体具有不同的热稳定性，并导致二聚化过程中出现两个阶段。事实上，根据超导量子干涉仪测量，1的磁矩在240 - 200 K和200 - 160 K的两个温度范围内二聚化时会逐步降低。
