A. Koll et al., STUDY OF THE ASSOCIATION OF 2-OXOINDOLINES IN CARBON-TETRACHLORIDE SOLUTIONS BY IR-SPECTRA, DIPOLE-MOMENTS AND AVERAGE MOLECULAR-WEIGHT MEASUREMENTS, Journal of physical organic chemistry, 7(4), 1994, pp. 171-177
Dipole moments, average molecular weights and IR spectra of 2-oxoindol
ine (I), 2-oxo-3-methylindoline (II) and 2-oxo-3,3-dimenthylindoline (
III) and their N-methyl-substituted analogues were studied in CCl4 sol
utions at various concentrations. It was shown that the molecules with
an N-H bond associate exclusively to cyclic dimers. The values of the
association constants (K) were determined by IR spectrometry. Other m
ethods gave too broad intervals of possible K values. The spectroscopi
c association constants of compounds I-III are very similar, 380, 350
and 370 dm3 mol-1, respectively. The v(s)(NH) band shift on associatio
n is 275 cm-1.