虽然具有 2 n +2 和 2 n +4 (n = 骨架原子数)骨架电子 (SE) 的碳硼烷广为人知,但关于具有奇数 SE 数的碳硼烷却鲜有报道。双笼组件的电化学测量(其中两个 C-苯基-邻碳硼基基团通过对亚苯基或对四氟亚苯基桥连接)揭示了两个良好分离且可逆的双电子还原波,表明形成了稳定的双阴离子和四阴离子。通过用金属钠还原分离出双阴离子的盐,并通过 X 射线晶体学测定了它们的不寻常结构。抗磁性二价阴离子包含两个 2 n +3 SE 簇,其中每个簇具有相当长的碳硼烷 C-碳硼烷 C 距离,约为 2.4 Å。亚苯基桥内的 π 共轭对于稳定这些具有奇数 SE 的碳硼烷起着重要作用。
Haloaryl Carboranes. I. 1,4-Bis[2-phenyl-1,2-dicarba-closo-dodecaboran(12)-1-yl]-2,3,5,6-tetrafluorobenzene
摘要:
The title molecule, C22H30B20F4, has a crystallographically imposed inversion centre. The twist angle (theta) of the phenyl ring is 15.6(3)degrees, and that of the haloaryl ring is 3.7(3)degrees. These low values are presumably a consequence of the mutual steric crowding of the rings. The C-cage-C-cage distance is 1.730(3) Angstrom, in good agreement with that found in similar molecules.