الفهرس 
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Abstract
enough[71 (pKI = 1.07 and PK2 = 2.24) to form a variety of complexes ranging from
non-polar,relatively weak adducts to strongly polar proton transfer species. The results of
this work should give more information about the correlation between IR, NMR and UV
”spectra,indicating the critical range and the shape of the proton potential.
EXPERIMENTAL
Chloranitie acid, solvents a nd the amiucs used in this investigation were of Mcrck spcctroscopic
grade.Acetonitrile was used without further treatment, while chloroform was dried by passing through
alumina.The liquid amines were dried over potassium hydroxide and distilled through 0.25 fractionating
columnshortly before use and stored in brown bottles, The complexes of chloranilic acid with arnines
wereprepared by precipitation from cquimolar solutions of the components in acetonitrile. The color of
chloranilieacid in acetonitrile is dark violet, suggesting the presence of IIA- [7]. Elemental chlorine
analysisprovided that 1: 1 complexes were formed. The melting points and the observed and calculated
elementalchlorine analysis arc listed in Table 1. IR spectra have been measured on a Pcrkin-Elmcr 1430
recordingspcctromctcr by using Kllr pellets. The NMR spectra were recorded on a high-resolution
llriikcrAM300L spectromctcr with Me4Si as the internal standard. The position of the bridge proton
(011 or Nil) was located hy carrying out the spectra in presence of ))20 where the 011 or Nil hand
disappears.lJV spectra were taken on a Shimadzu 160-A UV-VIS recording spectrophotometer, cmployinga
l-cm matched silica cell in the wavelength range 200-800 nm. The concentration of all the
studied lJV solutions was 10-4 M. All UV and NM R samples were prepared in a dry box.
RESULTS AND DISCUSSION
mspectra: 11\C variation of the lR spectra with increasing the pKa values of the amines
is illustrated in Figure l, which is, to a large extent, similar to those reported for other systems
(l01. Figure la represents the IR spectrum of chloranilic acid, where a broad band appears at
3553 cm-1 representing the intramolecular hydrogen bonding between the -OH and the
neighbouring carbonyl group. Another broad, intense band appears at 3230 cm”, corresponding
to polymeric OH bonding. The doublet at 1672 and 1627 ern”! represent symmetric and
asymmetric carbonyl groups, respectively. Figure lb represents the molecular hydrogenbonded
complex, 2,4-dimethylquinoline. The IR spectrum of this complex resembles that of
chloranilic acid in the OH stretching region, where a broad, intense, and almost symmetrical
stretching vibration vs(OH) band appears. A similar situation is observed for the spectrum of
Iheslrongly polar complex tri-n-butylamine (Figure 1 g), where proton transfer has evidently
IIIkenplace. One can see a considerable resemblance of the VOII band for the hydrogen bonded
complex and the VNII+ band for the proton transfer ion pair. Passing through the inversion
region (spectra le, l d and le), quite different spectra can be seen. The most striking feature
of these spectra is the broadening of the protonic band, and the hydrogen bonded complexes
absorb over almost the entire IR region, creating so called continua. Another feature of these
spectra is the presence of a very broad background absorption band down to 400 cm ”, as
clearly observed in the 1R spectrum of 3-methylisoquinol ine (spectrum Ic) and the diminution
of the intensity of the vs(OIl) stretching vibration, band in the usual range 2000-2500 crn’”.
The strongly anharmonic potential which can be anticipated for complexes in the proton
transfer region causes coupling with the internal vibrations or the complex components,
giving rise to the occurrence olEvan holes [11]. In case of the CA complexes with 5,6,7,8-
tctrahydroquinolinc and 2,4-dimethylpyridine (spectra Id, le), especially two sharp Evan
holes were recorded at 567 and 830 crn ”, resulting from the coupling between the skeletal
pyridinc ring vibration and the protonic vibration. Even in the case where a continuous
absorption occurs, in most systems a band appears on the high frequency side which Illay be
assigned to asymmetric vibration. It has, almost as a rule, a fine structure and is asymmetric.