ABIGAIL ASHA ABRAHAM

UNIVERSITY OF MALAYA

26/12/2014

Found everywhere and affects several organs in human.

Causes health problems in children and adults.

Many supplies, so it can be found excessively.

Sources of lead

Batteries

Alloys

Anticorrosion coatings

Lead based paints

Traditional medicines

Lead pipes, brass

plumbing fixtures

Benzo-subsitutedmacrocyclic diamides

Butyl-3-2(2-phenylhydrazono)indolin-

2-one

Podand derivatives

Derivatives of bis(phenylhydrazono-1H-

tetrazol-5-yl-acetonitriles)

Ligands from thiourea derivatives are able to form complexes with metals.

Heavy metals shows great affinity for soft coordination centers.

Synthesized ionophore consist N and S atoms which provides donor site to coordinate metal ions.

1,2-Bis(N’-benzoylthioureido)benzene (BBTB)

• GAUSSIAN 09 program

• To obtain optimized structure of the ligand and complex.

Theoretical study

• UV-Vis spectrophotometryExperimental

study

UV-Vis absorption spectra: (a) 1.0×10-3M Pb2+, (b) 2.0×10-4M 1,2-

bis(N’-benzoylthioureido) benzene ligand and (c) mixture of

ionophore and Pb2+ cation.

Spectrum of lead (L) shows a slight absorption maximum at 300nm

Ligand spectrum shows two absorption maximum at 320 and 350nm.

Addition of lead (II) to BBTB ligand, the absorption band shifts to 300nm and its intensity increases.

UV-Vis absorption spectra of BBTB ligand (2.3×10-6 M) in 1:1 MeOH:AN

mixture in the presence of increasing concentration of lead(II) and

absorbance versus the [Pb2+]/[BBTB] molar ratio plots.

The linear plot of absorbance versus the molar ratio of [Pb2+]/[ BBTB] shows a breaking point at 0.5

Formation of 2:1 [Pb: BBTB] complex.

BBTB + 2 Pb2+ BBTB(Pb)2

GAUSSIAN 09 program based on the density functional theory

To understand the functional interaction between BBTB ligand some metal cations

B3LYP / GENECP basis set was applied

BBTB ligand Complex with Pb2+ cation

Geometric parameters for optimized free and complexed BBTB

ligand with Pb2+ cations.

Comparison of geometric paramatersof BBTB with lead (II) ion

and BBTB with other studied cations.

Table: Binding energies ∆E, of BBTB with various cations by DFT

method, where EBTBT is -2018.976 (Hartree).

The binding energies, ∆E in the complexes

process between BBTB ligand and cations in

vacum are calculated according to the

following equation:

BBTB was applied as an ionophore for investigation the complex reactions with some cations.

The reaction between BBTB ionophore and lead (II) cations investigated by UV-Vis

With the purpose to elucidate the obtained experimental results, a density functional theory (DFT) study was conducted

The results demonstrate that the application of BBTB as a selective ionophore created cation-sensor for the quantification of lead (II) cations.