The Electron Spin Resonance of the Thermochromic Form of Bianthrone

Polyarenes II

“…As we noted in our original communication, whether concave-convex interactions should be treated as a new kind of intermolecular force or just a particular case of preorganization is not straightforward. In any case, it is worth considering them for the few curved guests of interest, mainly fullerenes and carbon nanotubes [154].…”

“…STM images have indeed revealed the appendages of aliphatic chains attached to SWCNTs via amide Reprinted with permission from [154]. Copyright 2008 National Academy of Sciences, USA Carbon Nanotubes: Synthesis, Structure, Functionalization, and Characterization reaction and localized them both at the tips and at the sidewalls.…”

“…The non-planarity of the π-electron system of BAEs leads to a bathochromic shift of the long-wavelength UV-vis absorptions as compared to a hypothetical planar conformation, in particular in the case where the central double bond is affected [108,127,[139][140][141]. In a long and controversial debate on the nature of the colored form, which was instrumental in forming today's understanding of the interrelation of color and structure in organic compounds, zwitterionic valence isomers [142] and betain-type mesomeric structures [143][144][145], biradicals [146][147][148][149][150][151][152][153][154], thermally populated triplets [109-111, 155, 156], cyclized forms [127,157,158] including Woodward and Wasserman's electrocyclized isomers [159], planar [13,[160][161][162][163][164][165], twisted [108, 112-114, 122, 125, 132, 134, 155, 158, 166-168], and double chair [116,129,169] conformations have been discussed as the colored B form. Today the puzzle is resolved [63] and it is generally accepted that the room temperature form A is the anti-folded conformation (a) [108,112,115,134,146,166,[170]…”