ABU DARDA Jamia Millia Islamia

3. Schiff base is a compound with a
functional group that contains a
carbon-nitrogen double bond with
the nitrogen atom connected to an
aryl or alkyl group.
General formula:

4. • Schiff base is usually formed by
condensation reaction of a carbonyl with
primary amine.

5. There are three main approaches to
prepare Schiff base ligand systems:
 Direct Synthesis
 Template Effect
 Conventional Method

6.  UV-Visible
 IR Spectroscopy
 1H and 13C NMR
 EPR
 Mass Spectrometry
 TGA/DTA
 Elemental Analysis
The Schiff base ligands and their complexes are
characterized on the basis of following:

7.  It is mainly applied for the detection of functional
groups (chromophore),the extent of conjugation ,
detection of polynuclear Compounds etc.
 The radiation in the wavelength range 200-400nm
corresponds to Ultra-violet region while radiation
in the wavelength range 400-800nm corresponds
to visible region.
 The absorption of radiation in the UV-visible
region causes the excitation of π electron in a
conjugation or an non conjugation system.
 Thus UV-visible spectrum is quite useful for
detection of conjugation, carbonyl group etc.

8. APPLICATIONS
 Identification of an unknown compound
 Examination of polynuclear hydrocarbons
 Elucidation of the structure of vitamins A and K
 Detection of two isomeric forms
 Determination of configurations of geometrical
isomers
 Identification of a compound in different solvents
 Determination of strength of hydrogen bonding
 Distinguishes between equatorials and axial
conformations
 LIMITATION : UV-visible spectrum does not
provide any information about the remaining part
of the molecule.

9. The formation of Schiff base complexes and
bonding modes are inferred from position of
characteristic bands in IR spectra and
resonance signals in 1H and 13 C-NMR spectra.
A strong intensity band(sharp) 1618-1622cm-1 v(C=N)
A medium intensity band 440-460 cm-1 v(M–N)
A weak absorption band 2906-2942cm-1 v(–CH3)
A broad absorption band 3330cm-1 v(–OH)

10. Nuclear magnetic resonance (NMR), induces changes
in the magnetic properties of certain atomic nuclei,
notably that of hydrogen(hydrogen atoms in different
environments can be detected, counted and analysed
for structure determination).
In the Nuclear magnetic resonance (NMR), radiations
of longest wavelength range,i.e., Radiowaves are
useful which lie in the frequency range about 60-
300MHz.

11. Electron paramagnetic resonance(EPR)
spectroscopy investigate those systems which are
organic or inorganic free radicals and ions of
transition metals which contain unpaired d or f
electrons.
Mass spectrometry is the most accurate method
for determining molecular mass of the compound
and its elemental composition and deduction of
molecular structure from fragments.
Mass spectrum of a substance is potted between
m/z values of ions versus relative abundance

12. The thermal stabilities of Schiff metal complexes are
investigate using (TGA/DTA) under N2 atmosphere
at a heating rate of 20 ◦C min-1 in the temperature
range 25-800 ◦C
The thermal analysis results are in agreement with
the elemental analysis findings.
Elemental analysis confirms the stoichiometry of
ligands and their complexes.

13.  Schiff base nitrogen donar ligands and
their complexes show biologically activities
i.e. toxicity against bacterial growth,
anticancerous, antimalarial antimicrobial,
antitubercoluosis and antifungal activities.
 Due to their resemblance with natural
proteins like hemerythrin enzymes they
are also used as biomimic model
compounds.

14.  They are potential inorganic and
organic cation receptors , electron
transfer agents , homogenous
catalysts and DNA , RNA interacting
agents.
 They also employed in
hydrometallurgy, material science as
luminescence materials and as non
linear optical materials.

15.  Schiff base ligands are formed by the condensation
reaction between aldehydes/ketones and aliphatic
amines.
 Their complexes are prepared by the interaction of ligands
with metal salts.
 The stoichiometry and the nature of bonding was
ascertained on the basis of elemental analysis and
conductivity data.
 The formation of the proposed compounds is inferred by
the appearance of imine bands in the IR and
corresponding proton resonance signals in the 1H spectra.
 Schiff base ligands and their complexes have numerous
applications in the field of pharmacy.

16.  H.Khanmohammadi et al./ Spectrochimica
Acta Part A 77 (2010) 342-347
 H. Keypour et al./ Polyhedron 51 (2013)
117-122
 M.Tyagi et al./ Spectrochimica Acta Part A :
Molecular and biomolecular specroscopy
118 (2014) 1056-1061
 T.A.Khan et al./ Spectroahimica Acta Part A
73 (2009) 622-629