Zinc(II) complexes of carboxamide derivatives: Crystal structures and interaction with calf thymus DNA

Two mononuclear zinc(II) complexes of newly designed carboxamide derivatives, formulated as [Zn(L1)3](ClO4)2 (1) and [Zn(L2)3](ClO4)2 (2) [where L1 = N-(furan-2-ylmethyl)-2-pyridinecarboxamide and L2 = N-(thiophen-2-ylmethyl)-2-pyridine-carboxamide], have been isolated in pure form in the reaction of perchlorate salts of Zn(II) with ligands L1 and L2, respectively. The two complexes were characterized by physicochemical and spectroscopic tools, and by X-ray crystal structures of both ligands and the complex 1. In complex 1, zinc(II) is chelated by three ligands with a distorted octahedral geometry. The DNA-binding properties of zinc complexes 1 and 2 have been investigated by spectroscopic methods and viscosity measurements. The results suggest that both complexes 1 and 2 bind to DNA in an intercalation mode between the uncoordinated furan or thiophene chromophore and the base pairs of DNA

A dysprosium-based metal-organic framework: Synthesis, characterization, crystal structure and interaction with calf thymus-DNA and bovine serum albumin

A dysprosium-based metallo-organic framework (MOF) containing calcium ions formulated as {Dy(pyda)3Ca1.5(H2O)6} \ub7 5.5H2O (1) (H2pyda = pyridine-2,6-dicarboxylic acid) was solvothermally synthesized in ethanolic medium and characterized by physico-chemical and spectroscopic tools. A detailed structural analysis of the solid state structure of 1 by single crystal X-ray diffraction study showed a tricapped trigonal prism geometry for lanthanide in the [Dy(pyda)3]3 12 fragment. The mode of interaction of 1 with calf thymus- DNA and with protein bovine serum albumin (BSA) was investigated by using absorption and emission spectroscopic tools. The apparent association constant of complex 1 with CT-DNA was deduced from an absorption spectral study (Kb = 4.08 7 104 M 121). Spectral and viscosity measurements indicated a groove-binding mode of 1 with CT-DNA, and from spectroscopic study the formation of a metal complex-BSA adduct was assumed to be the result of the interaction of 1 with BSA

Nickel(II) complexes of N2S2 donor set ligand and halide/pseudohalides: Synthesis, crystal structure, DNA and bovine/human serum albumin interaction

A series of neutral hexacoordinated nickel(II) complexes of formula [NiII(L)X2] (where L = 3,4-bis(2-pyridylmethylthio)toluene with tetradentate N2S2 donor set and X = chloride (1), azide (2), cyanate (3) and isothiocyanate anion (4)) have been synthesized and isolated in pure form. The complexes were characterized by physicochemical and spectroscopic methods along with detailed structural characterization of 1,2 and 3 by single crystal X-ray diffraction analyses. The structural study showed that the nickel(II) ion has a distorted octahedral geometry being chelated by the tetradentate N2S2 ligand and bound to cis- located choride or pseudohalide anions. In dimethylformamide solution the complexes showed quasi-reversible NiII/NiIII redox couples in cyclic voltammograms with E1/2 values of +0.723, +0.749, +0.768 and +0.868 V for 1, 2, 3 and 4, respectively. The study of interaction of the complexes with calf thymus DNA, bovine serum albumin (BSA) and human serum albumin (HSA) using spectroscopic and physicochemical tools clearly indicates that the complexes interact with DNA via groove binding mode

Synthesis, characterization, crystal structure and DNA-binding study of four cadmium(II) pyridine-carboxamide complexes

Treatment of perchlorate or nitrate salt of cadmium(II) with carboxamide derivatives (L) generated four novel mononuclear metal complexes, represented as [Cd(L )4](ClO4)2 (1a and 1b) and [Cd(L)2(ONO2)2] (2a and 2b) in appreciable yields (L = L1 = N-(furan-2-ylmethyl)-2-pyridine carboxamide and L = L2 = N-(thiophen-2-ylmethyl)-2-pyridine carboxamide). The complexes have been characterized by FT-IR, UV-Visible, elemental analysis and single crystal X-ray crystallographic analysis which revealed eight coordinated cadmium ions, but in different coordination environments, depending on the counter anion used. In addition, electronic absorption, fluorescence spectroscopy and viscosity measurements revealed a significant interaction of the four complexes with CT-DNA via intercalative/groove binding mode. The intrinsic binding constant Kb obtained varies from 0.4 7 10 4 to 1.11 7 10 5 M 121. The results suggest that neutral complexes 2a and 2b bind to DNA in an intercalative mode. On the other hand, cationic complexes 1a and 1b bind with DNA via weak electrostatic/covalent interaction

Multi-objective optimization of electroless ternary Nickel–Cobalt–Phosphorous coating using non-dominant sorting genetic algorithm-II

Study of electroless Nickel–Cobalt–Phosphorous coating was conducted on pure Copper substrate. The weight percentages of Nickel and Cobalt in the deposited mass, evaluated through energy dispersive X-ray analysis, have been selected as the response variables for statistical analysis. A response surface model with central composite design is developed to explain the effect of curvature in the predicted responses. Student’s t test has identified that concentration of Cobalt Sulfate is the significant process parameter for both the responses. The response surface plots and p-values have predicted the same. Fisher’s F test confirms that the response surface equation has excellent fitting to the observed values. A multi-objective optimization method has been employed in a quest to obtain the optimal values of process parameters, to maximize the responses. The Pareto optimal front of solutions, obtained from NSGA-II, provides more flexibility to the decision maker with the values of the optimal process parameters

Palladium (II) and platinum (II) complexes of deprotonated N, N´-bis (2-pyridinecarboxamide)-1, 2-benzene: synthesis, structural characterization and binding interactions with DNA and BSA

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Al3+-Ion-Triggered Conformational Isomerization of a Rhodamine B Derivative Evidenced by a Fluorescence Signal - A Crystallographic Proof

A newly designed rhodamine B anisaldehyde hydrazone exhibits Al3+-ion-induced cis (L) to trans (L) conformational isomerization with respect to the xanthene moiety through a rotation about a N-N bond; the isomerization is indicated by a detectable naked-eye color change and a turn-on red fluorescence in 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) buffer (EtOH/Water 1:9 v/v; pH 7.4) at 25 degrees C. In support of this observation, detailed spectroscopic and physicochemical studies along with density function theory (DFT) calculations have been performed. This cis-to-trans conformational isomerization is due to Al3+ ion coordination, which induces this visual color change and the turn-on fluorescence response. To strengthen our knowledge of the conformational isomerization, detailed structural characterizations of the cis and trans isomers in the solid state were performed by single-crystal X-ray diffraction. To the best of our knowledge, this is the first structural report of both cis and trans conformational isomers for this family of compounds. Moreover, this noncytotoxic probe could be used to image the accumulation of Al3+ ions in HeLa and MCF-7 cell lines

Nickel(II) complexes with 2-(pyridin-3-ylmethylsulfanyl)phenylamine and halide/pseudohalides: Synthesis, structural characterisation, interaction with CT-DNA and bovine serum albumin, and antibacterial activity

A new series of hexacoordinated octahedral nickel(II) complexes of 2-(pyridin-3-ylmethylsulfanyl)phenylamine (L) formulated as [Ni(L)4(X)2] (1\u20134) [where X = Cl- (1); NCO- (2); N3- (3) and NCS- (4)] has been synthesised and characterised by physicochemical, spectroscopic tools. Details of structural study of complex 1 using single crystal X-ray crystallography showed that distorted tetragonal environment around nickel(II) ion has been satisfied by four pyridinic-N donors of four organic moieties (L) and two chloride ions. All the complexes are redox active and the electrochemical study of the complexes showed only cathodic NiII/NiI redox couples in the range of -0.61 to -695 V versus Ag/AgCl. Interactions of 1 towards calf thymus-DNA by spectroscopic, viscosity-measurement and electrochemical study and towards bovine serum albumin (BSA) with the help of absorption and fluorescence spectroscopy were examined. Antibacterial activity of the complexes (1\u20134) studied by agar disc diffusion method showed the comparable inhibition activity of the nickel(II) complexes against some pathogenic bacteria namely Escherichia coli, Vibrio cholerae, Streptococcus pneumonia, Shigella sp. and Bacillus cereus

A quinazoline derivative as quick-response red-shifted reporter for nanomolar Al3+ and applicable to living cell staining

A newly synthesized and structurally characterized quinazoline derivative (L) has been shown to act as a quick-response chemosensor for Al3+ with a high selectivity over other metal ions in water-DMSO. In the presence of Al3+, L shows a red-shifted ratiometric enhancement in fluorescence as a result of internal charge transfer and chelation-enhanced fluorescence through the inhibition of a photo-induced electron transfer mechanism. This probe detects Al3+ at concentrations as low as 1.48 nM in 100 mM HEPES buffer (DMSO-water, 1 : 9 v/v) at biological pH with a very short response time (15-20 s). L was applied to biological imaging to validate its utility as a fluorescent probe for monitoring Al3+ ions in living cells, illustrating its value in practical environmental and biological systems

A napthelene-pyrazol conjugate: Al(III) ion-selective blue shifting chemosensor applicable as biomarker in aqueous solution

A newly synthesized and crystalographically characterized napthelene-pyrazol conjugate, 1-(5-phenyl-1H-pyrazole-3-ylimino)-methyl]-naphthalen-2-ol (HL) behaves as an Al(III) ion-selective chemosensor through internal charge transfer (ICT)-chelation-enhanced fluorescence (CHEF) processes in 100 mM HEPES buffer (water-DMSO 5 : 1, v/v) at biological pH with almost no interference of other competitive ions. This mechanism is readily studied from electronic, fluorimetric and H-1 NMR titration. The probe (HL) behaved as a highly selective fluorescent sensor for Al(III) ions as low as 31.78 nM within a very short response time (15-20 s). The sensor (HL), which has no cytotoxicity, is also efficient in detecting the distribution of Al(III) ions in HeLa cells via image development under fluorescence microscope