Dielectric Relaxation of NaClO4 Solutions in
Formamide, N-Methylformamide, and N,N-Dimethylformamide
J. Barthel, K. Bachhuber, and R. Buchner
Z. Naturforsch. 50a, 65-74 (1995).
Abstract
Complex permittivity spectra in the frequency range 0.95 <= nu/GHz
<= 89 for N,N-dimethylformamide (DMF), N-methylformamide (NMF),
formamide (FA) and their solutions of NaClO4 are
investigated to study the change of liquid structure and dynamics
arising from the availability of one hydrogen-bond acceptor site
together with no (DMF), one (NMF), or two (FA) donor sites on the same
molecule. Three solvent relaxation processes are observed for NMF and
two for FA and DMF. The relaxation parameters are used to determine
solvation numbers. They show that ion-solvent interactions lead to a
reduction of the average length of the H-bonded NMF chains but have
only moderate influence on the FA structure. An additional solute
relaxation process in DMF solutions is due to the diffusion-controlled
formation and decomposition of solvent-shared ion pairs.
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(c) 1998 Herbert Poepke
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