10.1021/ja027437m.s001 Kenji Matsuda Kenji Matsuda Matthew T. Stone Matthew T. Stone Jeffrey S. Moore Jeffrey S. Moore Helical Pitch of <i>m</i>-Phenylene Ethynylene Foldamers by Double Spin Labeling American Chemical Society 2002 radical helical ethyl acetate solvents measurement Phenylene Ethynylene Foldamers ethynylene label Spin oligo chloroform conformation ESR spectra oligomer Helical analysis phenylene Pitch 2002-09-14 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Helical_Pitch_of_i_m_i_-Phenylene_Ethynylene_Foldamers_by_Double_Spin_Labeling/3645027 To investigate the helical conformation of oligo(<i>m</i>-phenylene ethynylene)s, a pair of TEMPO spin labels were appended to the backbone. The two TEMPO radicals were separated by the four, five, and six repeating units. ESR spectra of the labeled oligomers were measured in chloroform and in ethyl acetate solvents in which the oligomers are disordered and folded, respectively. The measurement and analysis of ESR spectra revealed that six repeating units make one helical turn.