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Conformations of end-labeled alkanes in a rigid polymer matrix were investigated using the pulsed double electron-electron resonance (DEER) method. To this end, dipolar spectra of a series of aliphatic dicarbonic acids with 8−20 methylene units and chain ends bifunctionalized with nitroxide radicals were recorded in a polystyrene matrix. The biradicals are derived from hindered amine light stabilizers (HALS), used as polymer additives. Analysis of the dipolar spectra allows the determination of the end-to-end distances of the oligomer biradicals. The experiments show that the “flexible” alkane chains are almost completely stretched. This observation is consistent with the results of force field calculations.

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Pulsed EPR measurements of the transverse and longitudinal relaxation times of the C« -anion radical in crystalline C«-tetraphenylphosphoniumchloride were done at temperatures from 4 to 40 K. Above 40 K to room temperature the longitudinal relaxation time was taken from the cw-EPR linewidth. The low-temperature data are explained in terms of local magnetic fluctuations, slow C«motion, and localized two-level states related with the local disorder. The relaxation data at higher temperatures reveal experimental evidence for the Jahn-Teller distortion of the C6p -anion radical and allow to determine the Jahn-Teller splitting between the az"electronic ground state and the excited el"state of the unpaired electron.

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We compare infrared spectra of the C60 monoanion in different solid-state structures with each other as well with that of the neutral molecule. We relate the shift and splitting of the Tu infrared modes to the strength and anisotropy of electron-phonon coupling in those environments.

The new fullerite C60−PΦ4+ · (ClPΦ4)2 was investigated by EPR and static susceptibility. Charge transfer from PΦ4 to C60 was found to be incomplete. C60−PΦ4+ separates into a system of localized and delocalized spins at higher temperatures. At 40 K an Anderson-type localization occurs. The low-temperature susceptibility is shown to be a mixture of a Curie susceptibility and a contribution that resembles the behaviour of a spin singlet with an activated low-lying triplet state. The EPR linewidth below 40 K is only about 400 mG.