الفهرس 
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Abstract
This thesis comprisesthree chapters:-
1- The frist chapter include the introduction which
deals with the chemistry of the molecular compounds,
classification of electron donors, acceptors and
complexes formed from them. This chapter also
includes a literature survery of the work on charge
transfer complexes of aromatic nitro-compounds.
2- The second chapter comprise the details for the
experimental work including the preparation of
the donors, the acceptors used and the methods
for obtaning the solid
spectroscopic technique
CT complexes. The different
and the apparatus applied
in these studies are described.
3- The third chapter is devoted to the results and
discussion of the work carried out on the CT complexes
included in the thesis.
The infrared absorption spectra of the CT complexes
under investigation are recorded in the solid state
as KBr discs, the bands of diagnostic importance
are reported. The results show that the YCH bands
of the acceptors display generally a shift to lower
wvaenumbers where as thgse of the donor display an
opposite shift, which is characteristic of charge
1transfer of the 11 - 11* type.
The ir spectra of charge transfer complexes with
acidic acceptors (I. II. III and IV) are characterized
by a group of bands within the 2400-3000 -1 cm range
corresponding to the stretching mod~of a proton attached
to a positive quaternary nitrogen of the group
(H-N ~ which is formed through the transfer of a proton
I
from the acidic center of the acceptor to basic one
of the donor.
The symmetric N02 bande s in the CT complexes
become more broader and show some splitting indicating
higher differentation in their energy states. The
higher energy asymmetric N02 band is either shifted
to higher wavenumber or remains at the same position
which may be due to n- 11* interaction. A substantial
support for the results obtained from the ir spectra
is gained by considering the changes of the NMR spectra
of some molecular complexes under investigation in
comparison to those of their constituents. As a matter
of fact the signal due to the aromatic protons of
the donor parts are shifted downfields while those
of the acceptors parts exhibit a reverse displacement.
Such shifts are due to the decreased electron density
on the ring and its
which results from the
increase on the acceptor ones
intermolecular 11 -11 * interaction.
Then in the CT complexes the protons of the donor
part are less shielded than in the free donor molecule.
On the other hand the protons of the acceptor part
are more shielded compared to those of the free accepton
The U.V and visible absorption spectra of the
charge transfer complexes are recorded using the Nujal
mull technique. The electronic absorption spectra
one CT band, which can be assigned to
of all CT complexes under investigation display only
* CT interaction.
The appearance of one band denotes that no
w-w * interaction is liable to occur-e • This is further
substituted by calculating the energy of the CT interaction
(ECT) using the relation given by Briegleb:-
The electron affinities of some acceptors are determined
from the values of ECT· A plot of ECT as a function
of Ip is a more or less linear relation. The
value of EA determined from this plot is comparable
to that obtained from Briegleb equation.
# where C is the colomic factor.