Ambidentate salicylaldimines N-(3-aminopropyl) morpholine: coordination behaviour towards copper, nickel and zinc divalent ions and biological applications / Nurul Azimah binti Ikmal Hisham

Ikmal Hisham, Nurul Azimah (2013) Ambidentate salicylaldimines N-(3-aminopropyl) morpholine: coordination behaviour towards copper, nickel and zinc divalent ions and biological applications / Nurul Azimah binti Ikmal Hisham. Masters thesis, University of Malaya.

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Abstract

Two flexidentate Schiff-base ligands condensed from salicylaldehyde or 5-chlorosalicylaldehyde with N-(3-aminopropyl)morpholine were prepared in situ and reacted with zinc(II), copper(II) and nickel(II) salts. These compounds were characterised by elemental analyses and various physico-chemical techniques. Single crystal X-ray analyses were carried out on nine different complexes. Upon complexation, the Schiff bases underwent deprotonation at the hydroxyl to act as mono-anionic ligands. When a ligand:metal ratio of 2:1 was applied, the deprotonated Schiff bases coordinated metal ions through phenolate and imine groups in a square-planar or tetrahedral geometry. In contrast, 5-chlorosalicylaldimine reacted with the metal ions in a 1:1 ratio to form complexes wherein morpholine nitrogen also participates in an N,N,O-tridentate coordination mode. The structures of the complexes were characterized by spectroscopic methods and single crystal X-ray diffraction. The Schiff bases and their metal complexes were evaluated for cytotoxic and antioxidant activity. Cytotoxic screening was carried out against human breast cancer cells with positive estrogen receptor (MCF-7), human breast cancer cells with negative estrogen receptor (MDA-MB-231), and colon cancer cell line (HT-29). This cytotoxicity also was tested on two normal cells, normal liver cells (WRL-68) and normal colon cell lines (CCD-841). The Schiff bases L1H, was found to be very active against breast cancer with positive estrogen receptor cells and also colon cancer cells with the lowest IC50 values. Antioxidant screening was carried out by using ferric reducing antioxidant power (FRAP) assay. All compounds were found to have low activity except for L1H ligand with FRAP value higher than the standard BTH and Trolox.

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