@article{suzuki_takeda_kawai_fujiwara_2008, 
  title={Ultralong C-C bonds in hexaphenylethane derivatives}, 
  volume={80}, 
  DOI={10.1351/pac200880030547}, 
  abstractNote={<jats:p>The longer C-C bond than the standard (1.54 Å) is so weakened that it is cleaved easily, as found in the parent hexaphenylethane (HPE). However, the compounds with an ultralong C-C bond (1.75 Å) can be isolated as stable solids when the bond-dissociated species does not undergo any reactions other than bond reformation. This is the central point in designing the highly strained HPEs, which were obtained by two-electron reduction of the corresponding dications. Steric repulsion of "front strain" is the major factor to expand the central C-C bond of HPEs. During the detailed examination of the ultralong C-C bond, the authors discovered the intriguing phenomenon of "expandability": the C-C bond length can be altered over a wide range by applying only a small amount of energy (1 kcal mol</jats:p>}, 
  publisher={Walter de Gruyter GmbH}, 
  author={Suzuki and Takeda and Kawai and Fujiwara}, 
  year={2008}, 
  month={Jan}
  }