An infrared study of CD3CN in isopropanol, dimethyl formamide, and dimethyl sulfoxide

The vibrational characteristics of deuterated acetonitrile dissolved in iso propanol, dimethyl formamide (DMF), and dimethyl sulfoxide (DMSO) have been studied. Observed vibrational bands show substantial frequency shifts, the amounts of which vary almost linearly with concentration. The absorption f eature in the region of 2220-2280 cm(-1) was deconvoluted to the consisting absorption bands. The band at 2258 cm(-1) of pure CD3CN, which is on the l ow frequency side of the monomer C=N stretch (upsilon (2)), is attributed t o the C=N stretch of the dimer (upsilon'(2)). The shoulder found on the fur ther low frequency side of the upsilon (2) band, particularly in dilute sol ution, is believed to be due to vs, and its frequency and intensity vary la rgely as a function of concentration along with those of other vibrational bands involved with the CD3 group. The upsilon (5) band of pure CD3CN is be lieved to be active and located at about 2251 cm(-1). Ab initio calculation s have also been performed for the solute-solvent complexes, CD3CN-DNF and CD3CN-DMSO, at the NP2/6-31 + G(2d,p) level assuming anti-parallel configur ations. The calculated results show a good agreement with the observed resu lts. (C) 2001 Elsevier Science B.V. All rights reserved.