Bharathiar University

About: Bharathiar University is a education organization based out in Coimbatore, Tamil Nadu, India. It is known for research contribution in the topics: Thin film & Adsorption. The organization has 5812 authors who have published 8628 publications receiving 143934 citations. The organization is also known as: BU.

Effect of substitution and planarity of the ligand on DNA/BSA interaction, free radical scavenging and cytotoxicity of diamagnetic Ni(II) complexes: A systematic investigation

Abstract: Four new bivalent nickel hydrazone complexes have been synthesised from the reactions of [NiCl2(PPh3)2] with H2L {L = dianion of the hydrazones derived from the condensation of salicylaldehyde or o-hydroxy acetophenone with p-toluic acid hydrazide (H2L1) (1), (H2L2) (2) and o-hydroxy acetophenone or o-hydroxy naphthaldehyde with benzhydrazide (H2L3) (3) and (H2L4) (4)} and formulated as [Ni(L1)(PPh3)] (5), [Ni(L2)(PPh3)] (6), [Ni(L3)(PPh3)] (7) and [Ni(L4)(PPh3)] (8). Structural characterization of complexes 5–8 were accomplished by using various physico-chemical techniques. In order to study the influence of substitution in the ligand and its planarity on the biological activity of complexes 5–8 containing them, suitable hydrazone ligands 1–4 have been selected in this study. Single crystal diffraction data of complexes 5, 7 and 8 proved the geometry of the complexes to be distorted square planar with a 1 : 1 ratio between the metal ion and the coordinated hydrazones. To provide more insight on the mode of action of complexes 5–8 under biological conditions, additional experiments involving their interaction with calf thymus DNA (CT DNA) and bovine serum albumin (BSA) were monitored by UV-visible and fluorescence titrations respectively. Further, the ligands 1–4 and corresponding nickel(II) chelates 5–8 have been tested for their scavenging effect towards OH and O2− radicals. The effect of complexes 5–8 to arrest the growth of HeLa and Hep-2 tumour cell lines has been studied along with the cell viability against the non-cancerous NIH 3T3 cells under in vitro conditions.

Potentially cytotoxic new copper(II) hydrazone complexes: synthesis, crystal structure and biological properties

Abstract: A new set of penta-coordinated copper(II) hydrazone complexes containing solvated methanol were synthesized by reacting the hydrazone ligands, 2-acetylpyridine benzoyl hydrazone (HL1) and 2-acetylpyridine thiophene-2-carboxylic acid hydrazone (HL2), with [CuCl2(DMSO)2] and characterized by different spectral methods. Single crystal X-ray diffraction studies of the complexes revealed that both of them, [CuCl(L1)(MeOH)] (1) and [CuCl(L2)(MeOH)] (2), have square pyramidal geometry around the cupric ion, in which the hydrazone is coordinated through NNO atoms along with a molecule of methanol in the apical position. Interaction of the ligands HL1 and HL2 along with the corresponding copper complexes 1 and 2 with calf thymus DNA (CT-DNA) has been estimated by absorption and emission titration methods which revealed that the compounds interacted with CT-DNA through intercalation. Binding of the compounds, i.e., free ligands and complexes (1) and (2) with bovine serum albumin (BSA) protein investigated using UV-visible, fluorescence and synchronous fluorescence spectroscopic methods indicated that there occurred strong binding of copper complexes to BSA over the ligands. Further, the cytotoxicity of the compounds examined in vitro on a panel of cancerous cell lines such as a human cervical cancer cell line (HeLa), a pancreatic cancer cell line (PANC-1), an Ehrlich ascites cancer cell line (EAC) and Dalton's lymphoma ascitic cancer cells (DLA) and a normal mouse embryonic fibroblasts cell line (NIH3) demonstrated that the complexes 1 and 2 possessed superior cytotoxicity than that of well-known commercial anticancer drug cisplatin to the tumor cells but are less toxic to the normal cell line and have emerged as potential candidates for further studies.

Finite-time stability analysis of fractional-order complex-valued memristor-based neural networks with time delays

Abstract: In this paper, the problem of finite-time stability of fractional-order complex-valued memristor-based neural networks (NNs) with time delays is extensively investigated. We first initiate the fractional-order complex-valued memristor-based NNs with the Caputo fractional derivatives. Using the theory of fractional-order differential equations with discontinuous right-hand sides, Laplace transforms, Mittag-Leffler functions and generalized Gronwall inequality, some new sufficient conditions are derived to guarantee the finite-time stability of the considered fractional-order complex-valued memristor-based NNs. In addition, some sufficient conditions are also obtained for the asymptotical stability of fractional-order complex-valued memristor-based NNs. Finally, a numerical example is presented to demonstrate the effectiveness of our theoretical results.