High-field EPR can be successfully used to study the dynamics of guest molecules in inclusion compounds. A radical guest has been obtained by gamma-irradiation of the inclusion compound nonadecan-10-one in perhydrotriphenylene. The rotational motion of the radicals inside the host channels is fast and the relaxation effect on the X-band EPR line shapes is small. The line widths of the W-band EPR spectra (108 GHz) are significantly larger since the molecular rotation modulates the g-tensor of the radical. Analysis of the relaxation effects shows that the X-band and W-band EPR are complementary. The former gives the maximum information at low temperature, while the latter is useful at higher temperatures. (C) 1999 Elsevier Science B.V. All rights reserved.
High-field EPR of irradiated inclusion compounds / Segre, Ulderico; M., Brustolon; L. C., Brunel; A. L., Maniero. - In: CHEMICAL PHYSICS LETTERS. - ISSN 0009-2614. - 308:(1999), pp. 408-412.