A novel water soluble ligand-bridged cobalt(II) coordination polymer has been synthesized by reacting the new ligand, 2-oxo-1,2-dihydroquinoline-3-carbaldehyde (isonicotinic) hydrazone (H(2)L) with ...Co(NO(3))(2)·6H(2)O and characterized by spectral, analytical and structural methods. Single crystal X-ray diffraction studies revealed that the Co(II) complex, {Co(H(2)L)(H(2)O)(2)(NO(3))(2)·3H(2)O}(n) has a slightly distorted octahedral geometry around the central Co(II) ion; the ligand is coordinated through the ONO donor atoms to one Co(II) metal center and bridged through the pyridine nitrogen atom to another similar Co(II) center so as to form a one-dimensional polymeric unit. The interaction of the ligand and the complex with calf thymus DNA (CT-DNA) has been explored by absorption and emission titration methods, which revealed that the compounds could interact with CT-DNA through intercalation. The interactions of the compounds with bovine serum albumin (BSA) were also investigated using UV-visible, fluorescence and synchronous fluorescence spectroscopic methods. The results indicated that the complex exhibited a strong binding to BSA over the ligand. Investigation of the antioxidative properties showed that the polymeric Co(II) complex has a strong radical scavenging potency against hydroxyl radicals, 2,2-diphenyl-1-picrylhydrazyl radicals, nitric oxide and superoxide anion radicals. Further, the cytotoxic effect of the compounds examined on cancerous cell lines, such as human cervical cancer cells (HeLa), human laryngeal epithelial carcinoma cells (HEp-2), human liver carcinoma cells (Hep G2), human skin cancer cells (A431) and non-cancerous NIH 3T3 mouse embryonic fibroblasts cell lines showed that the complex exhibited substantial anticancer activity.
Three novel complexes (1, 3 and 4) ligating N-substituted isatin thiosemicarbazone derivatives have been synthesized and their structural and biological characteristics have been compared with those ...of the known analogs (2, 5–7 and 8). In addition, the structure of the representative ligands (L1, L3 and L4) and complex (4) was confirmed by single crystal X-ray diffraction method. All the complexes (1–8) were assessed for their cytotoxic property against a panel of four human cancer cells such as HepG-2 (liver), MOLM-14 (acute monocytic leukemia), U937 (histiocytic lymphoma). and IM-9 (myeloma). Complex 4 exhibited prominent cytotoxic property against MOLM-14, U937 and IM-9 cell lines. Moreover, the results were compared with the well-known anticancer drugs like doxorubicin, cisplatin and daunorubicin. Besides, complex 4 enhanced the apoptotic cell death in IM-9 cell line and induced cell cycle arrest at G1 phase. Western blot analysis revealed the down-regulation of Bcl-2 (b-cell lymphoma-2), up-regulation of Bax (bcl-2 associated X protein), release of cytochrome c and activation of caspases-3 in IM-9 cells by complex 4. Importantly, complex 4 was not toxic to the normal Vero cell line (IC50 > 300 μM). In addition, complex 4 showed the concentration dependent cleavage of supercoiled (SC) DNA to its nicked circular (NC) form.
Isatin thiosemicarbazone based nickel(II) complex 4 showed promising anticancer activity, and induced morphological changes, apoptosis, cell cycle arrest at G1 phase in IM-9 cells. Display omitted
•Synthesis of Ni(II) complexes bearing tridentate isatin thiosemicarbazone ligands.•In vitro cytotoxicity of the complexes was examined against four human cancer cells.•One of the complexes (4) showed good anticancer activity against IM-9 cells.•Complex 4 induced morphological changes and cell cycle arrest at G0/G1 phase.•Complex 4 stimulated the apoptosis through mitochondrial signaling pathway.
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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.
A convenient synthesis of a library of tetrazoles through a novel and operationally simple protocol effecting the direct conversion of arylboronic acids catalyzed by a new ONO pincer-type Pd(II) ...complex under mild reaction conditions using the readily available reagents is reported. The palladium complex was reused up to four cycles in an open-flask condition.
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The reaction of 2-oxo-1,2-dihydroquinoline-3-carbaldehyde 4(
N,
N)-dimethylthiosemicarbazone (HL) with copper(II) nitrate in methanol yielded water soluble {Cu(L)(CH
3OH)}
2(NO
3)
2·H
2O. Structural ...analysis revealed that the complex consists of centrosymmetric binuclear entities containing square-pyramidal copper(II) ions bridged through the sulfur atoms. The spectroscopic experimental evidences strongly suggested that the ligand and complex could interact with calf thymus DNA (CT-DNA) through intercalation. A gel electrophoresis assay demonstrated the ability of the complex to cleave the pBR322 plasmid DNA. The complex also exhibited a strong binding to bovine serum albumin (BSA) over the ligand. Investigations of antioxidative properties showed that the complex has strong radical scavenging properties. Further, the cytotoxic effect of the complex was examined on HeLa, Hep G2, and HEp-2, which showed that the complex exhibited substantial cytotoxic specificity on HeLa over the other two.
A novel water soluble sulphur bridged binuclear copper(II) thiosemicarbazone complex has been synthesized. Its DNA and protein interactions, antioxidative, and cytotoxic activity have been explored.
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► A novel sulphur bridged binuclear copper(II) complex has been prepared. ► It binds to CT-DNA via intercalation and cleaves pBR322 plasmid DNA. ► The complex binds to BSA via hydrophobic interaction. ► It possesses significant antioxidative properties. ► It shows specific cytotoxicity against HeLa over Hep G2, HEp-2 cancer cells.
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Indole thiosemicarbazone ligands were prepared from indole-3-carboxaldehyde and N-(un)substituted thiosemicarbazide. The Ru(η6-p-cymene) complexes Ru(η6-p-cymene)(HL1)ClCl (1) and ...Ru(η6-p-cymene)(L2)2Cl2 (2*) were exclusively synthesized from thiosemicarbazone (TSC) ligands HL1 and HL2, and RuCl2(p-cymene)2. The compounds were characterized by analytical and various spectroscopic (electronic, FT-IR, 1D/2D NMR, and mass) tools. The exact structures of the compounds (HL1, HL2, 1, and 2*) were confirmed by single-crystal X-ray diffraction technique. In complexes 1 and 2*, the ligand coordinated in a bidentate neutral (1)/monobasic (2*) fashion to form a five-membered ring. The complexes showed a piano-stool geometry around the Ru ion. While 2* existed as a dimer, 1 existed as a monomer, and this was well explained through free energy, bond parameter, and charge values computed at the B3LYP/SDD level. The intercalative binding mode of the complexes with calf thymus DNA (CT DNA) was revealed by spectroscopic and viscometric studies. The DNA (pUC19 and pBR322 DNA) cleavage ability of these complexes evaluated by an agarose gel electrophoresis method confirmed significant DNA cleavage activity. Further, the interaction of the complexes with bovine serum albumin (BSA) was investigated using spectroscopic methods, which disclosed that the complexes could bind strongly with BSA. A hemolysis study with human erythrocytes revealed blood biocompatibility of the complexes. The in vitro anticancer activity of the compounds (HL1, HL2, 1, and 2*) was screened against two cancer cell lines (A549 and HepG-2) and one normal cell line (L929). Interestingly, the binuclear complex 2* showed superior activity with IC50 = 11.5 μM, which was lower than that of cisplatin against the A549 cancer cell line. The activity of the same complex (IC50 = 35.3 μM) was inferior to that of cisplatin in the HepG-2 cancer cell line. Further, the apoptosis mode of cell death in the cancer cell line was confirmed by using confocal microscopy and DNA fragmentation analysis.
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The water soluble mixed ligand complexes Cu(nal)(diimine)(H2O)(ClO4) 1–4, where H(nal) is nalidixic acid and diimine is 2,2′-bipyridine (1), 1,10-phenanthroline (2), 5,6-dimethyl-1,10-phenanthroline ...(3), and 3,4,7,8-tetramethyl-1,10-phenanthroline (4), have been isolated. The coordination geometry around Cu(II) in 1 and that in the Density Functional Theory optimized structures of 1–4 has been assessed as square pyramidal. The trend in DNA binding constants (Kb) determined using absorption spectral titration (Kb: 1, 0.79±0.1<2, 1.06±0.1<3, 1.79±0.2<4, 1.84±0.2×105M−1) is in line with that (Kapp) determined by competitive ethidium bromide binding studies. The large red-shift (10nm) observed for 2 suggests that the phen co-ligand is stacked with a frayed DNA base pair. In contrast, 3 and 4 are involved in intimate hydrophobic interaction with DNA through the methyl substituents on phen ring, which is supported by viscosity and protein binding studies. DNA docking studies imply that 4 is involved preferentially in DNA major groove binding while 1–3 in minor groove binding and that all the complexes, upon removing the axially coordinated water molecule, bind in the major groove. Interestingly, 3 and 4 display prominent double-strand DNA cleavage while 1 and 2 effect only single-strand DNA cleavage in the absence of an activator. The complexes 3 and 4 show cytotoxicity higher than 1 and 2 against human breast cancer cell lines (MCF-7). The complex 4 induces apoptotic mode of cell death in cancer cells.
The complexes Cu(nal)(diimine)(H2O)+ H(nal)=nalidixic acid, diimine=2,2′-bipyridine, 1,10-phenanthroline, 5,6-dimethyl-1,10-phenanthroline bind to DNA in minor groove while Cu(nal)(3,4,7,8-tmp)(H2O)+ 3,4,7,8-tmp=3,4,7,8-tetramethyl-1,10-phenanthroline binds in the major groove. The latter shows self-activated double-strand DNA cleavage and causes apoptotic cell death on MCF-7 cancer cells with potency higher than its analogues. Display omitted
•Water soluble complexes Cu(nal)(diimine)(H2O)+ H(nal)=nalidixic acid are isolated•When diimine is 1,10-phenanthroline, it is stacked with frayed DNA base pairs•The 3,4,7,8-tetramethyl-1,10-phenanthroline complex is bound in the DNA major groove•The 3,4,7,8-tetramethyl-1,10-phenanthroline complex shows double-strand DNA cleavage•All the complexes exhibit cytotoxicity with potency higher than cisplatin
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Self-assembled metallamacrocyclic Cu(II) and Ni(II) complexes of the types Cu(L1-O,S)3 (1), Ni(L1-O,S)3 (2), Cu(L2-O,S)2 (3) and Ni(L2-O,S)2 (4) H2L1 = ...3,3,3',3'-tetrabenzyl-1,1'-terephthaloylbis(thiourea) and H2L2 = 3,3,3',3'-tetrabenzyl-1,1'-isophthaloylbis(thiourea) were synthesized and characterized by analytical, spectroscopic (UV-Vis, FT-IR, mass, (1)H & (13)C NMR and EPR) and single crystal X-ray diffraction techniques. The crystal structures of Ni(L1-O,S)3 and Cu(L2-O,S)(Py)2 showed the formation of self-assembled 3:3 and 2:2 metallamacrocyclic Cu(II) and Ni(II) complexes respectively. The binding affinity and binding mode of the trinuclear complexes toward CT DNA were determined by UV-Vis spectrophotometric titrations and the fluorescent indicator displacement (FID) assay. The interaction of the ligand (H2L1) and the complexes (1 and 2) with BSA was investigated using UV-Vis and fluorescence spectroscopic methods. Absorption and emission spectral studies indicate that the complexes 1 and 2 interact with CT DNA and BSA protein more strongly than their parent ligand. Both the complexes (1 and 2) cleaved the pBR 322 plasmid DNA in the absence of an external agent. Complex 1 IC50 = 22.36 (A549) and 10 μM (MCF7) exhibited higher cytotoxicity than cyclophosphamide against A549 and MCF7 cancer cell lines. The IC50 value of 2 (29.24) is lower in the A549 cell line and slightly higher (18.04) in the MCF7 cell line than that of cyclophosphamide IC50 = 41.84 (A549) and 11.89 μM (MCF7).
A series of Ru(ii)( eta 6-p-cymene) complexes (1-4) bearing the general formula RuCl2( eta 6-p-cymene)L (L = monodentate aroylthiourea ligand) has been synthesized and characterized by analytical and ...various spectroscopic techniques. The neutral monodentate coordination of aroylthiourea with Ru via an S atom was confirmed by single crystal X-ray diffraction study. The complexes were tested for their ability to interact with DNA and protein. The complexes bound with calf thymus DNA (CT DNA) with the intrinsic binding constant value in the order of 104 M-1. The intercalative mode of binding was confirmed by the ethidium bromide (EB) displacement study. The interaction of the complexes with CT DNA was further supported by viscosity measurements and circular dichroic (CD) spectra. The Ru(ii) complexes cleaved the supercoiled DNA without the need of any external agent. The spectroscopic evidence showed good binding efficacy of the complexes with BSA (Bovine Serum Albumin). The alterations in the secondary structure of BSA by the Ru(ii) complexes were confirmed by synchronous fluorescence spectra. Cytotoxicity examination by MTT assay was carried out in two cancer cell lines (MCF7 and A549) and one non-cancerous cell line (L929). Complex 4 showed significant activity IC50 = 52.3 (MCF7) and 54.6 (A549) mu M which was comparable with that of similar known complexes. The morphological changes assessed by Hoechst staining revealed that the cell death occurred by apoptosis.
Self‐assembly of organic small molecules into an ordered thin film has been the key strategy towards efficient charge transport for organic field‐effect transistors (OFETs). Solution processing is a ...feasible and economic way to enhance pi–pi interaction. Herein, nitrile‐substituted unsymmetrical triarylamines for OFET applications with high mobility are reported. The compounds were constructed by Suzuki cross‐coupling reactions under inert conditions. The HOMO level of about 5.3 eV indicates good hole‐transporting ability. OFETs were assembled in bottom‐gate, top‐contact architecture. Devices fabricated from a binary solvent system exhibited excellent p‐channel characteristics, with impressively high charge‐carrier mobility of up to 2.58 cm2 V−1 s−1 and ION/OFF current ratios of 106–107. SEM and AFM analysis showed the efficient molecular self‐assembly attained by the simple and effective solvent‐engineering method. Theoretical insights obtained by DFT calculations supported by single‐crystal structures showed that the crystalline nature and packing modes of these compounds ensure high mobility. The results prove that these compounds have great potential for use in numerous electronic applications, such as sensors and logic switches.
TAA OFETs: A series of nitrile‐substituted triarylamines (TAAs) was developed for use as solution‐processable organic field effect transistors (OFETs). The CN group was introduced to alter the twist and tilt angles of TAA and thus attain an unsymmetrical structure. TAA‐based devices exhibited pronounced p‐channel behavior with high charge‐carrier mobility and large ON/OFF current ratio (see scheme).
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