الفهرس 
GENERAL INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
New lanthanide complexes of the general formulae [Ln(L) (NO3)(H2O)] have been synthesized by reaction of Ln(NO3)3.xH2O {Ln = La, Sm and Yb} with 2,2’-(((1E,1’E)-thiophene-2,5-diylbis(methaneylylidene))bis (azaneylylidene))diphenol (H2L). Based on elemental analysis and spectroscopic analysis (UV-Visible, FT-IR, ESI-MS, 1H and 13C NMR), molar conductance, and magnetic moment, an eight -coordinated structure has been proposed.
The results showed that the Schiff base ligand acted as a pentadentate dibasic donor coordinating through the azomethine nitrogen, deprotonated hydroxyl group, and thiophene sulphur atom. In vitro anti microbial studies by well diffusion method expressed as the diameter of the growth inhibition area in millimeters revealed that, the new complexes exhibited higher antimicrobial activity than the free parent Schiff base ligand against the same organisms. The interaction of the synthetic compounds with CT-DNA has been studied to investigate their anticancer and antitumor activities by the electronic spectroscopy, fluorometric competition studies with ethidium bromide and DNA viscosity measurements. Furthermore, due to the ligand and its Ln(III) complexes exhibit good DNA binding affinity, it is considered worthwhile to investigate their antioxidant activity. The data have shown that, the complexes are more effective inhibitors towards reactive oxygen species (ROS), such as superoxide anion and hydroxyl radical, because of the formation of coordination compounds, the scavenger effect can be enhanced in presence of rare earth metal ions. The activity of test compounds in ascending order La complex > Sm complex > Yb complex > H2L in terms of IC50 value. The anticancer activities of the complexes have also been studied towards human colon carcinoma cancer (HCT-116) and human breast cancer (MCF-7) cell lines. The % Cell Viability and IC50 values indicates that La(III) complex (1) has higher sensitivity than Sm(III) complex (2), Yb(III) complex (3) and the free ligand.