Date of Award

1-1-2016

Thesis Type

phd

Document Type

Thesis

Divisions

science

Department

Faculty of Science

Institution

University of Malaya

Abstract

A new series of bis-benzimidazolium salts namely, L1.Br, L2.Br, L3.Br, L1.PF6, L2.PF6 and L3.PF6 have been successfully synthesized and characterized by using fourier transform infrared (FT-IR), 1H and 13C nuclear magnetic resonance (NMR), and CHNS elemental analysis. The crystal structure of L1.Br and L1.PF6 were confirmed, by single crystal X-ray diffraction analysis. The selective complexation of synthesized bisbenzimidazolium salts were found by using conductometric method. L1.Br has been used to study the complexation process with Ni2+, Zn2+, Pd2+, Hg2+ and Ag+ metal ions in MeOH:H2O binary phases at different temperatures. The stoichiometric of the complexation reactions for Ni2+, Zn2+, and Pd2+ are 1:1 [M:L1.Br]. While, for Hg2+ and Ag+, two stoichiometries were obtained (2:1 [M:L1.Br] and 1:1 [M:L1.Br]). The stability constants (log ) obtained from GENPLOT software show that the values for Hg2+ and Ag+ ions are higher than the other metal ions. The thermodynamic parameters ( , , )    C C C G H S revealed that the complexations of L1.Br in all cases were found to be enthalpy destabilized but entropy stabilized. The negative value of calculated  C G is an evidence to prove the ability of the ligand to form stable complexes with metal cations and the process trends to proceed spontaneously. The experimental data was tested by using artificial neural network (ANN) program and was in a good agreement with the estimated data. The calculations based on density fuctional theory (DFT) were used to predict the metal binding capability of complexes. The combination of all the results revealed that the selective complexation of L1.Br is in the sequence of Ni2+

Note

Thesis (PhD) – Faculty of Science, University of Malaya, 2016.

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