Synthesis,characterization, and DNA-binding of [Co(phen)2(CPIA)]3+, [Co(phen)2(BIP)]3+, and [Co(phen)2(CIP)]3+

Three ligands, 2-(3-(carboxymethyl)-1,10-phenanthroline-[5,6-d]imidazole-1-yl)acetate (CPIA), 2-(benzo[d][1,3]dioxol-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (BIP), and 2-(9H-carbazol-3-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (CIP), and their complexes, [Co(phen)₂(CPIA)]³⁺ (1) (phen = 1,10-phenanthroline), [Co(phen)₂(BIP)]³⁺ (2), and [Co(phen)₂(CIP)]³⁺ (3), have been synthesized and characterized. Binding of the three complexes with calf thymus DNA (CT-DNA) has been investigated by spectroscopic methods, cyclic voltammetry, and viscosity measurements. The three complexes bind to DNA through an intercalative mode, and the size and shape of the intercalative ligands have significant effects on the binding affinity of complexes to CT-DNA.     

Synthesis,characterization, photocleavage,antimicrobial activity and DNA binding of [Co(bpy)2MHPIP]3+, [Co(dmb)2MHPIP]3+, and [Co(phen)2MHPIP]3+ complexes

4-Methyl-2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline) (MHPIP) and its complexes [Co(bpy)₂MHPIP]³⁺ (1) (bpy = 2,2′-bipyridine), [Co(dmb)₂MHPIP]³⁺ (2) (dmb = 4,4′-dimethyl-2,2′-bipyridine), and [Co(phen)₂MHPIP]³⁺ (3) (phen = 1,10-phenanthroline) have been synthesized and characterized by UV/VIS, IR, EA, ¹H, ¹³C-NMR, and mass spectra. The binding of the three complexes with calf-thymus-DNA (CT-DNA) has been investigated by absorption and emission spectroscopy, DNA-melting techniques, viscosity measurements, and DNA cleavage assay. The spectroscopic data and viscosity results indicate that these complexes bind to CT-DNA via an intercalative mode. The complexes also promote photocleavage of plasmid pBR322 DNA and were screened for antimicrobial activity.     

Synthesis,characterization and biological activities of two novel orthopalladated complexes: Interactions with DNA and bovine serum albumin,antitumour activity and molecular docking studies

[Pd(L₁)(C,N)]CF₃SO₃ and [Pd(L₂)(C,N)]CF₃SO₃ (L₁ = 2,2′ ‐bipyridine, L₂ = 1,10‐phenanthroline and C,N = benzylamine) novel orthopalladated complexes have been synthesized and characterized using various techniques. The binding of the complexes with native calf thymus DNA (CT‐DNA) was monitored using UV–visible absorption spectrophotometry, fluorescence spectroscopy and thermal denaturation studies. Our results indicate that these complexes can strongly bind to CT‐DNA via partial intercalative mode. In addition, fluorescence spectrometry of bovine serum albumin (BSA) with the complexes shows that the fluorescence quenching mechanism of BSA is a static process. The results of site‐competitive replacement experiments with specific site markers clearly indicate that the complexes bind to site I of BSA. Notably, the complexes exhibit significant in vitro cytotoxicity against two human cancer cell lines (Jurkat and MCF‐7) with IC₅₀ values varying from 37 to 53 μM. Finally, a molecular docking experiment effectively proves the binding of the Pd(II) complexes to DNA and BSA.     

Three novel Ni(II), VO(II) and Cr(III) mononuclear complexes encompassing potentially tridentate imine ligand: Synthesis,structural characterization,DNA interaction,antimicrobial evaluation and anticancer activity

Three novel Cr(III),VO(II) and Ni(II) imine complexes derived from the condensation of 2‐aminophenol (AP) with 2‐hydroxynaphthaldehyde (HN) were synthesized. The prepared HNAP imine ligand and its complexes were investigated via various physicochemical tools. The results suggest that the parent ligand behaves as a dibasic tridentate ONO ligand, when coordinated to Cr(III) in octahedral and to Ni(II) in tetrahedral geometry. In the case of VO(II), it coordinates in distorted square pyramidal geometry. Also, the prepared compounds were screened for their antimicrobial activities against pathogenic bacteria, Escherichia coli (−ve), Bacillus subtilis (+ve) and Staphylococcus aureus (+ve), and some types of fungi, Aspergillus niger , Candida glabrata and Trichophyton rubrum . The results indicate that the complexes show a stronger antimicrobial efficiency compared to the pro‐ligand. The interaction of the prepared complexes with calf thymus DNA was investigated using spectral, viscosity and gel electrophoresis measurements. The obtained results clearly demonstrate that the binding affinity with calf thymus DNA follows the order HNAPCr > HNAPV > HNAPNi. The cytotoxic activity of the prepared compounds on human colon carcinoma cells (HCT‐116 cell line), hepatic cellular carcinoma cells (HepG‐2cell line) and breast carcinoma cells (MCF‐7cell line) was examined. From these results it is found that the investigated complexes have potent cytotoxicity against growth of carcinoma cells compared to the corresponding imine pro‐ligand.     

Nuclease activity of redox/non-redox active binuclear transition metal mixed-polypyridine complexes: [M2(1,4-tpbd)(diimine)2(H2O)2]4+, M = Zn,Co, Ni,Cd, diimine = phen,bpy, dafo

Seven new transition metal complexes formulated as [M₂(1,4-tpbd)(diimine)₂(H₂O)₂]⁴⁺ [M = Zn, Co, Ni, Cd; 1,4-tpbd = N,N,N′,N′-tetrakis(2-pyridylmethyl)benzene-1,4-diamine; diimine is a N,N-donor heterocyclic base like 1,10-phenanthroline (phen), 2,2′-bipyridine (bpy), 4,5-diazafluoren-9-one (dafo)] have been synthesized and structurally characterized by X-ray crystallography: [Zn₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (1), [Zn₂(1,4-tpbd)(bpy)₂(H₂O)₂]⁴⁺ (2), [Co₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (3), [Ni₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (4), [Ni₂(1,4-tpbd)(bpy)₂(H₂O)₂]⁴⁺ (5), [Ni₂(1,4-tpbd)(dafo)₂(H₂O)₂]⁴⁺ (6) and [Cd₂(1,4-tpbd)(phen)₂(H₂O)₂]⁴⁺ (7). Single crystal diffraction reveals that the metals in the complexes are all in a distorted octahedral geometry. The interactions of the seven complexes with calf thymus DNA (CT-DNA) have been investigated by UV absorption, fluorescence, circular dichroism spectroscopy and viscosity measurements. The apparent binding constants (K_app) are calculated to be 5.2?×?10⁵ M^?1 for 1, 1.05?×?10⁵ M^?1 for 2, 5.76?×?10⁵ M^?1 for 3, 4.57?×?10⁵ M^?1 for 4, 1.29?×?10⁵ M^?1 for 5, 1.7?×?10⁵ M^?1 for 6, 2.53?×?10⁵ M^?1 for 7, the binding propensity to the calf thymus DNA in the order: 3 (Co-phen) > 1 (Zn-phen) > 4 (Ni-phen) > 7 (Cd-phen) > 6 (Ni-dafo) > 5 (Ni-bpy) > 2 (Zn-bpy). Furthermore, these complexes display efficient oxidative cleavage of supercoiled DNA; the Zn(II)/H₂O₂ and Cd(II)/H₂O₂ systems efficiently cleave DNA attributed to the peroxide ion coordinated to the Zn(II) and Cd(II), which enhanced their nucleophilicity, this is rare.     

Synthesis,characterization and some reactions of trans-[Co(NH3)4(CH3NH2)Br]2+ and trans-[Co(NH3)4(CH3NH2)(NO3)]2+ complexes

The preparation of trans-[Co(NH₃)₄(CH₃NH₂)Br]²⁺ and trans-[Co(NH₃)₄(CH₃NH₂)-(NO₃)]²⁺ complexes is described. The UV-VIS spectra of the complexes indicate a decrease of the ligand field compared to the parent pentaammines. Infrared spectra match with the pattern of the corresponding pentaammines. The catalyzed (by Hg²⁺) aquation of the trans-bromomethylamine complex go under retention of the stereochemical configuration. The base hydrolysis (studied at 25°C) products show trans to cis rearrangement for both complexes. ¹H NMR spectroscopy is used for identification of the stereochemical configuration of the compounds.     

Interaction studies of DNA binding of ruthenium(II) mixed-ligand complexes: [Ru(phen)2(dtmi)]2+ and [Ru(phen)2(dtni)]2+

Two new ligands, 3-(pyrazin-2-yl)-as-triazino[5,6-f]-5-methoxylisatin (dtmi), 3-(pyrazin-2-yl)-as-triazino[5,6-f]-5-nitroisatin (dtni) and their ruthenium(II) complexes [Ru(phen)2(dtmi)](ClO4)2 (1) and [Ru(phen)2(dtni)](ClO4)2 (2) have been prepared and characterized by elemental analysis, FAB-MS, ES-MS and 1H NMR. The DNA-binding behaviors of complexes have been studied by spectroscopic titration, viscosity measurements, thermal denaturation and circular dichromism (CD). The results indicate that the complexes 1 and 2 interact with calf thymus DNA (CT-DNA) by intercalative mode. The DNA-binding affinity of the complexes 2 is larger than that complex 1 does.     

Two novel windmill-like tetrasupporting heteropolyoxometalates: [MoVI7MoVVIV8O40(PO4)][M(phen)2(OH)]2[M(phen)2(OEt)]2 (M=Co,Ni)

Two interesting neutral tetrasupporting heteropolyoxometalates: [Mo^VI₇Mo^VV^IV₈O₄₀(PO₄)][M(phen)₂(OH)]₂[M(phen)₂(OEt)]₂·xH₂O (phen=1,10-phenanthroline, EtOH=ethanol, M=Co, x=7, 1; M=Ni, x=6, 2) were hydrothermally prepared and structurally characterized. The mixed molybdenum–vanadium polyoxoanion [Mo^VI₇Mo^VV^IV₈O₄₀(PO₄)]⁴⁻ exist in both two complexes, which acts as a bridge to covalently link two pairs of transition metal complex fragments, generating neutral windmill-like trimetallic nanocluster polyoxometalates. Variable-temperature magnetic susceptibility measurements of complexes 1 and 2 reveal that antiferromagnetic exchange interaction exists in this type of trimetallic tetrasupporting heteropolyoxometalates.     

用二维核磁共振研究[Co(phen)2(HNAIP)]Cl3配合物与错配及正常寡聚核苷酸的作用

为了开发能识别正常与错配核酸的探针, 首次合成了[Co(phen)₂(HNAIP)]Cl₃金属配合物, 并利用二维核磁研究了此配合物与错配d(CCGAATGAGG)₂及正常d(CCTAATTAGG)₂寡聚核苷酸的相互作用, 首次发现, [Co(phen)₂(HNAIP)]Cl₃是从“大沟”插入到错配碱基对G₃A₄和G₇A₈之间, 能够很好地识别G:A错配; 而[Co(phen)₂(HNAIP)]Cl₃与正常的寡聚核苷酸的作用, 则是从小沟插入, 即[Co(phen)₂(HNAIP)]Cl₃与错配和正常寡聚核苷酸在不同位置及不同沟槽存在明显的插入式结合、并且有明显的差异, 这就有可能被用来作为识别正常与错配寡聚核苷酸的探针.     

Synthesis,structural characterization and molecular modelling of bidentate azo dye metal complexes: DNA interaction to antimicrobial and anticancer activities

A novel azo dye ligand, namely 1‐[(5‐mercapto‐1H‐1,2,4‐triazole‐3‐yl)diazenyl]naphthalen‐2‐ol (HL), was synthesized. Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺ and UO₂²⁺ complexes were also prepared by the treatment of HL with Mn(CH₃COO)₂?4H₂O, Co(CH₃COO)₂?4H₂O, Ni(CH₃COO)₂?4H₂O, Cu(CH₃COO)₂?H₂O, CuCl₂?2H₂O, Cu(NO₃)₂?6H₂O and UO₂(NO₃)₂?6H₂O. The structures of these metal chelates were confirmed using elemental, spectral, magnetic moment, molar conductance and thermal analyses. The analytical data confirmed the formation of the chelates in 1:1 (metal‐to‐ligand) ratio having the formula [ML(H₂O)X]Y?H₂O, where M is Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺ or UO₂²⁺; X is Cl^?, NO₃^? or CH₃COO^?; and Y is H₂O. The azo compound acts in a monobasic bidentate manner via the nitrogen and oxygen atoms of azo and hydroxyl groups, respectively. All complexes were found to have tetrahedral structures, except the UO₂²⁺ complex that showed octahedral geometry. The mode of interaction between the synthesized complexes and calf thymus DNA was explored by the aid of absorption spectroscopy and viscosity measurements. The azo dye and its chelates were evaluated against the growth of various bacterial and fungal strains (Escherichia coli, Staphylococcus aureus, Aspergillus flavus and Candida albicans) with insight gained into the effect of type of metal centre, type of coordinated anion and position of the metal in the periodic table on the activity of the complexes. The geometric structure of the complexes was optimized using molecular modelling. The in vitro cytotoxicity of the synthesized compounds was tested against HEPG2 cell line.     

Ni(phen)3]2Sb18S29: a novel three-dimensional framework thioantimonate(III) templated by [Ni(phen)3] complexes

A novel thioantimonate(III), namely, [Ni(phen)(3)](2)Sb(18)S(29) (1; phen = 1,10-phenanthroline), has been solvothermally synthesized. Its structure features a three-dimensional framework with the largest channels in thioantimonates. The chiral [Ni(phen)(3)](2+) cations and the Sb:S ratio (1:1.611) in 1 are unique among those in the reported thioantimonates. The thermal stability, optical properties, and electric conductivity as well as the theoretical band structure and density of state of 1 have also been studied.     

Applying Cu(II) complexes assisted by water-soluble porphyrin to DNA binding and selective anticancer activities

Cancer is one of the killers endangering human health and its treatment has always been a focus of the medical community. For anticancer drugs, water-soluble porphyrin and Schiff bases have always been of interest. We report here three Cu(II)-based complexes functionalized by water-soluble cationic porphyrin and hydrazine Schiff base, which were prepared and evaluated for their biological activity. The three Cu(II) complexes all exhibited potent binding affinity to calf thymus DNA, the strongest interaction being between CuP2 and DNA. We studied the cytotoxicity of the complexes and ligands against different types of cancer cells (A549, H-1975, HepG2 and T47D), results showing the ligands are less cytotoxic; therefore, the anticancer activity of the complexes is improved by complexation. Furthermore, the cytotoxicity of ligands and complexes was also evaluated against the normal cell line Hs 578Bst, complexes showing more negligible cytotoxicity than ligand. Moreover, the cellular uptake of these Cu(II) complexes was investigated using the extraction method and results suggested that CuP2 exhibits the best cellular uptake towards H-1975 cells. Interestingly, fluorescence microscopy experiments and flow cytometric analysis (cell cycle) were used to further investigate the potent anticancer activities.     

Synthesis,characterization and DNA binding and photocleavage studies of [Ru(bpy)2BDPPZ]2+, [Ru(dmb)2BDPPZ]2+ and [Ru(phen)2BDPPZ]2+ complexes and their antimicrobial activity

Polypyridyl ligand 9a,13a‐dihydro‐4,5,9,14‐tetraaza‐benzo[b]triphenylene‐11‐yl)‐phenyl‐methanone (BDPPZ) and its complexes [Ru(bpy)₂BDPPZ]²⁺, [Ru(dmb)₂BDPPZ]²⁺ and [Ru(phen)₂BDPPZ]²⁺ (where bpy = 2,2′‐bipyridine, dmb = 4,4′‐dimethyl‐2,2′‐bipyridine, phen = 1,10‐phenanthroline) have been synthesized and characterized by elemental analysis, IR, UV–vis, ¹H‐NMR, ¹³C‐NMR and mass spectra. The DNA‐binding properties of the complexes were investigated by absorption, emission, melting temperature and viscosity measurements. Experimental results indicate that the three complexes can intercalate into DNA base pairs. Photo activated cleavage of pBR‐322 DNA by the three complexes was also studied. Further, all three Ru(II) complexes synthesized were screened for their antimicrobial activity. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis,characterization and biological studies of alkenyl‐substituted titanocene(IV) carboxylate complexes

The carboxylate compounds [Ti(η⁵‐C₅H₅)(η⁵‐C₅H₄{CMe₂(CH₂CH₂CH?CH₂)})(O₂CCH₂SXyl)₂] (2; Xyl = 3,5‐Me₂C₆H₃) and [Ti(η⁵‐C₅H₅)(η⁵‐C₅H₄{CMe₂(CH₂CH₂CH?CH₂)})(O₂CCH₂SMesl)₂] (3; Mes 1 = 2,4,6‐Me₃C₆H₂) were synthesized by the reaction of [Ti(η⁵‐C₅H₅)(η⁵‐C₅H₄{CMe₂(CH₂CH₂CH?CH₂)})Cl₂] (1) with 2 equivalents of xylylthioacetic acid or mesitylthioacetic acid, respectively. Compounds 2 and 3 were characterized by spectroscopic methods. The cytotoxic activity of 1–3 was tested against human tumor cell lines from four different histogenic origins—8505C (anaplastic thyroid cancer), DLD‐1 (colon cancer) and the cisplatin sensitive A253 (head and neck cancer) and A549 (lung carcinoma)—and compared with those of the reference complex [Ti(η⁵‐C₅H₅)₂Cl₂] (R1) and cisplatin. Surprisingly, the cytotoxic activities of the carboxylate derivatives were lower than those of their corresponding dichloride analogue (1). However, complexes 1–3 were more active than titanocene dichloride against all the studied cells with the exception of complex 2 against A253 and A549 cell lines. DNA‐interaction tests were also carried out. Solutions of all the studied complexes were treated with different concentrations of fish sperm DNA, observing modifications of the UV spectra with intrinsic binding constants of 2.99 × 10⁵, 2.45 × 10⁵, and 2.35 × 10⁵ M ^?1 for 1–3. Structural studies based on density functional theory calculations of 2 and 3 were also carried out. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis,characterization, antimicrobial,DNA binding,and oxidative cleavage activities of Cu(II) and Co(II) complexes with 2-(2-hydroxybenzylideneamino)isoindoline-1,3-dione

(E)-2-(2-hydroxybenzylideneamino)isoindoline-1,3-dione (Hbid) was prepared by condensation of N-aminophthalimide and salicylaldehyde and characterized by elemental analysis, IR, ¹H-NMR, and mass spectral studies. Mononuclear complexes [(phen)Cu^II(μ-Hbid)₂H₂O] (1), [(phen)Co^II(Cl)₂(μ-Hbid)]6H₂O (2) (phen?=?1,10-phenanthroline) and binuclear complexes [Cu^II(μ-Hbid)]₂ (3), and [Co^II(μ-Hbid)]₂ (4) with Hbid were prepared and characterized by elemental analysis, IR, UV-Vis, molar conductance, and thermogravimetric (TG) techniques. DNA-binding properties of 1–4 were investigated by UV spectroscopy, fluorescence spectroscopy, and viscosity measurements. The results suggest that 1 and 2 bind to DNA by partial intercalation, whereas 3 and 4 find different groove-binding sites. The cleavage of these complexes with super coiled pUC19 has been studied using gel electrophoresis; all the complexes displayed chemical nuclease activity in the absence and presence of H₂O₂ via an oxidative mechanism. Complexes 1–4 inhibit the growth of both Gram-positive and Gram-negative bacteria.     

Synthesis and spectroscopic DNA binding studies of [Ru(phen)2(tbtc)]2+ and [Ru(2,9-dmp)2(tbtc)]2+

A new polypyridyl ligand tbtc (tbtc=4,5,9,14-tetraaza-benzo[b]triphenylene-11-carboxylic acid methyl ester) and its complexes [Ru(phen)2(tbtc)]2+ (1) (phen=1,10-phenanthroline) and [Ru(2,9-dmp)2(tbtc)]2+ (2) (2,9-dmp=2,9-dimethyl-1,10-phenanthroline) were synthesized and characterized by element analysis, MS, and 1H NMR. The DNA binding properties of both complexes to calf thymus DNA (CT-DNA) were investigated by different spectrophotometric methods and viscosity measurements. The results suggest that both complexes bind to DNA via an intercalative mode, and the DNA binding affinity of complex 1 is much greater than that of complex 2. This difference in binding affinity probably was caused by the different ancillary ligands. Also, when irradiated at 365 nm, complex 1 was found to be a more-effective DNA-cleaving agent than complex 2.     

Synthesis,characterization, and DNA-binding of Ln(III) complexes with 2-hydroxybenzylidene-2-phenylquinoline-4-carbonylhydrazone

2-Hydroxybenzylidene-2-phenylquinoline-4-carbonylhydrazone (H₂L) and five Ln(III) complexes, [Ln(H₂L)(NO₃)₂]NO₃ [Ln = La (1), Pr (2), Sm (3), Eu (4), and Tb (5)], have been synthesized and characterized by ¹H NMR, elemental analysis, conductivity measurements, mass spectra, IR spectra, and UV spectra. The interaction of these complexes with calf thymus DNA was investigated by UV absorption spectroscopy, fluorescence spectroscopy, circular dichroism spectroscopy and viscosity measurements. Results suggest that these complexes bind to DNA via groove binding.     

Co(II), Ni(II), Cu(II) and Zn(II) complexes of isatinyl‐2‐aminobenzoylhydrazone: synthesis,characterization and anticancer activity

This article describes the synthesis, structural aspects and biological studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes of a new hydrazone derived from the condensation of isatin and 2‐aminobenzoylhydrazide. The ligand is well characterized using ¹H NMR, ¹³C NMR, 2D HETCOR, mass and IR spectral studies. The chelating tendency of the ligand towards transition metal ions is established using analytical and spectral studies, which reveal the monobasic tridentate nature of the ligand. Octahedral geometry for Co(II), Cu(II) and Zn(II) and tetrahedral geometry for Ni(II) are tentatively proposed. All the synthesized compounds were screened for in vitro anticancer activity against Ehrlich ascites carcinoma and human cancer cell lines (adenocarcinoma HT29, kidney cancer cell line K293 and breast cancer cell line MDA231) using tryphan blue exclusion method and MTT assay. Copyright © 2014 John Wiley & Sons, Ltd.     

Synthesis,characterization and binding studies of novel diorganotin(IV) complexes of sodium 2‐mercaptoethanesulfonate

Diorganotin(IV) complexes ( 1‐4) of MESNA (sodium 2‐mercaptoethanesulfonate HSCH₂CH₂SO₃Na) and a mixed ligand complex of dibutyltin(IV), 1,10‐phenanthroline and MESNA ( 5 ) were synthesized with thermal and microwave assisted methods. All the complexes were characterized thoroughly with the help of analytical and various spectroscopic techniques viz. FTIR, NMR (¹H, ¹³C, and ¹¹⁹Sn NMR) spectroscopy and ESI‐MS spectrometery. Various spectrophotometric studies were carried out to decipher the binding mode of MESNA and its diorganotin complexes 1 ‐ 5 with calf thymus DNA (CT DNA) and thus, to calculate the binding constant (K_b). Absorption spectrophotometric study confirmed the interaction is through partial intercalation of all the complexes including MESNA, inside the DNA helix and calculated binding constant (K_b) is in the order of 10³ M^‐1. A series of emission spectrophotometric experiments support the results obtained through the absorption spectrophotometric studies. Circular dichroic (CD) spectroscopic analysis and viscosity measurement of CT DNA further complemented the fact that the partial intercalation plays a major role in the interaction of the studied complexes with CT DNA. All the studies corroborated that complex 2 bound to CT DNA with maximum affinity followed by complex 5 among all the complexes. Involvement of hydroxyl radicals as an active species in the cleavage activity of pBR322 plasmid DNA is proved by carrying out agarose gel electrophoretic technique.