Stereodynamics and Characterization of the Hexa(4-n-dodecylbiphenylyl)- benzene Hexaanion that Includes a Twisted Benzene Core

Hexa(4-n-dodecylbiphenylyl)benzene (HDBB) was reduced by a series of alkali metals in THF under high vacuum. Three reduction states were identified by NMR spectroscopy, namely the dianion, tetraanion and hexaanion. The NMR spectra of HDBB6− revealed a remarkable distortion of symmetry, which is interpreted by adoption of a twisted conformation of the central benzene ring and a slow rotation of the inner phenylene rings of the biphenyl units. Due to the surprising thermal stability of the hexaanion, a dynamic NMR investigation revealed the pseudorotation of the twisted conformation and the phenylene rotation mentioned above.