Microwave-assisted synthesis, characterization and anticancer activity of tetranuclear schiff base complexes

• Main Authors: Khaidir, Siti Solihah, Bahron, Hadariah, Tajuddin, Amalina Mohd, Ramasamy, Kalavathy
• Format: Article
• Published: Universiti Malaysia Terengganu 2022
• Subjects: QD Chemistry
• Online Access: http://eprints.um.edu.my/43613/

A hexadentate Schiff base 6,6’-((1E,1’E)-(1,3-phenylenebis(azanylylidene)) bis(methanylylidene))bis-(2-methoxyphenol) (L) was synthesized via condensation of o-vanillin and m-phenylenediamine. Its tetranuclear Cu(II), Co(II) and Zn(II) complexes were obtained through microwave-assisted complexation with corresponding acetate salts in a 1:2 ratio of L:M. The compounds were elucidated through CHN elemental analysis, molar conductivity, magnetic susceptibility (MSB), thermogravimetric analysis (TGA), Infrared (IR), UV-Visible, 1H and 13C NMR spectroscopy. The ν(C=N), ν(C-O)phenolic and ν(C-O)methoxy peaks shifted to higher wavenumber upon complexation, with the appearance of new peaks assignable to ν(M-N) and ν(M-O) at 651-671 and 424-441 cm-1, respectively, indicating that L coordinated to metal centres through its azomethine N, phenolic O and methoxy O. The Cu4(L)2 and Co4(L)2 complexes were paramagnetic with μeff of 1.85 and 3.84 B.M., respectively; whereas the Zn4(L)2 displayed the expected diamagnetism. The thermal decomposition of all complexes showed a two-stage process at around 100°C and 300°C. An anticancer investigation against human colorectal cancer (HCT116) cell lines revealed that the parent ligand possessed lower activity than its metal complexes. Cu4(L)2 exhibited the highest anticancer activity with IC50 of 6.56 ± 1.26 μM © Penerbit UMT