Effect of ligand substitution on DNA binding ability of two new square planar copper(II)–Schiff base complexes (original) (raw)
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Central European Journal of Chemistry, 2006
The new homodinuclear complexes 1–4 of the type [LMII 2Cl2], heterotrinuclear complexes 5 and 6 of the type [LMII 2SnIVCl6] where M = CuII, MnII, CoII, NiII and CuII and NiII, respectively have been synthesized and characterized by elemental analysis and various spectroscopic techniques. The homodinuclear complexes possess two different environments (N2 and N2O2donor sets) for holding the metal ions. The metal ion in N2 set exhibits square planar geometry with two chloride ions in the inner sphere but rhombic structure is found in tetradentate N2O2 Schiff base cavity while in heterotrinuclear complexes SnIV atom is in the octahedral environment. The interaction of complexes 1 and 5 with calf thymus DNA was carried out by absorption spectroscopy and cyclic voltammetry. The intrinsic binding constants (K b) of complex 1 and 5 were determined as 3.2 × 103 M−1 and 9.6 × 103 M−1, respectively suggesting that complex 5 binds more strongly to CT-DNA than complex 1. Fluorescence studies alo...
Journal of the Mexican Chemical Society
Three new copper(II) complexes (1-3) with general formula [Cu(HL)CH3COO] of N-salicyl-βamino alcohol Schiff bases containing, (S)-(+)-phenyl glycinol, (1S, 2R)-2-amino-1, 2-diphenylethanol and 1, 1, 3-triphenyl-(R)-(+)-2-amino propanol, were synthesized. Their structures were characterized by FTIR, LCMS, magnetic moment, molar conductance and elemental analysis data. DFT calculations proposed distorted square planar geometries for the complexes. The calculated IR spectra are in good agreement with the experimental IR spectra, confirming the proposed structures. Their interactions with calf thymus DNA were investigated and their binding constants Kb were found. Gel electrophoresis reveals that all complexes display significant nuclease activity against supercoiled pentry/d-topo plasmid DNA.
Polyhedron, 2019
Two tetranuclear Schiff base copper(II) complexes, namely[Cu 4 (L) 2 (LH) 2 (H 2 O) 2 ](ClO 4) 2 •3H 2 O (1) and [Cu 4 (L) 2 (LH) 2 (H 2 O) 2 ](ClO 4)•(tp) 0.5 •3H 2 O (2) (where H 2 L = 2-[(2-hydroxy-ethylimino)methyl]-6-methoxy-phenol, tp = terephthalate), were synthesized and characterized by X-ray single crystal diffraction. Both complexes 1 and 2 are comprised of structurally similar tetranuclear cationic [Cu 4 (L) 2 (LH) 2 (H 2 O) 2 ] 2+ species with a double open cubane core, in which the two metal centers possess a square pyramidal environment and the other two exhibit a slightly distorted octahedral coordination geometry. The interaction of complexes 1 and 2 with calf thymus DNA (CT-DNA) was investigated using electronic absorption and fluorescence studies, and the results showed that the complexes interact with CT-DNA with the related intrinsic binding constants (K ib) of 1.8×10 6 and 1.1×10 7 L mol-1 for 1 and 2, respectively. Their interactions with bovine serum albumin (BSA) and human serum albumin (HSA) were also investigated and spectroscopic techniques showed that both complexes interact with these proteins through a ground state association process. Using 3,5-di-tertbutylcatechol(3,5-DTBC) as a model substrate, both complexes show catecholase-like activity, being able to oxidase 3,5-DTBC to 3,5-di-tert-butylquinone (3,5-DTBQ) in the presence of oxygen.
Journal of Inorganic Biochemistry, 2008
A new series of mixed-ligand mono-or hetero-trihalide Cu(II) complexes of the type [Cu(dienXX)Y(YZ 2)], where dienXX = Schiff dibase of diethylenetriamine with 2-thiophene-carboxaldehyde (dienSS), 2-furaldehyde (dienOO) or 2-pyrrole-2-carboxaldehyde (dienNN), Y = Cl, Br and Z = Br, I was synthesized by the reaction of the precursors of the type [Cu(dienXX)Y]Y with iodine or bromine in 1:1 molar ratio. The distorted square pyramidal configuration of the new homo-and hetero-trihalide Cu(II) mononuclear complexes was identified by C, H, N, Cu analysis, spectroscopic methods (IR, UV-visible), molar conductivity and magnetic measurements. The basal plane consists of three nitrogen atoms of the Schiff base and one halogen (terminal) atom while another axially located trihalogen moiety occupies the fifth side of the square pyramid as a YZ 2 entity, adopting an almost linear configuration. The equilibrium geometry of these complexes was further corroborated by theoretical studies at the B3LYP/DGDZVP level. A series of quantum chemical descriptors (e.g. SOMO (singly occupied molecular orbital) LUMO (lowest occupied molecular orbital), SOMO and LUMO energies, SOMO-LUMO gap, dipole moment, polarizability, molar volume, etc.) have been utilized in order to deduce quantitative structure-activity relationships (QSARs). The effect of the new compounds on the single stranded (ss), double stranded (ds) and pDNA led either to the formation of a DNA-complex cationic adduct, or to its degradation, evidenced by DNA electrophoretic mobility and DNA interaction spectroscopic titration studies. Moreover, the antimicrobial activity of Cu(II) complexes against Gram(+) and Gram(À) bacteria can be attributed to the synergistic action of the dissociation species, namely the cationic [Cu(dienXX)Y] + and anionic [YZ 2 ] À ones. Finally, de Novo linear regression analysis correlating the bioactivity of these complexes with their structural substituents has been carried out, leading to some interesting qualitative observations/conclusions.
2015
Department of Chemistry, Raghunathpur College, Purulia-723 133, West Bengal, India E-mail : mr.bbiswas@rediffmail.com Department of Chemical Sciences, Indian Institute of Science Education & Research, Kolkata-741 252, India Department of Microbiology, Bharathidasan University, Tiruchirappalli-620 024, Tamilnadu, India Department of Chemistry, Urumu Dhanalakshmi College, Tiruchirappalli-620 019, Tamilnadu, India Manuscript received online 02 January 2014, revised 14 August 2014, accepted 24 August 2014 Syntheses and structural characterization of two copper(II) complexes, [Cu(L)] (1) and [Cu<sub>2</sub> (L)(NCS)(H<sub>2</sub>O)<sub>2</sub> ] (2) [L = <em>N,N´</em>-bis(salicyaldehydene)-1,3-diaminopropan-2-ol] have been reported. The structure of 1 has been determined by single crystal X-ray diffraction study while spectroscopic characterization has been performed to determine the structure for 2. Complex 1 crystallizes in <em>P<...
Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 2011
Two neutral mononuclear Cu(II) complexes have been prepared in EtOH using Schiff bases derived from 4-toluoyl pyrazolone and thiosemicarbazide. Both the ligands have been characterized on the basis of elemental analysis, IR, 1H NMR, 13C NMR and mass spectral data. The molecular geometry of one of these ligands has been determined by single crystal X-ray study. It reveals that these ligands exist in amine-one tautomeric form in the solid state. Microanalytical data, Cu-estimation, molar conductivity, magnetic measurements, IR, UV–Visible, FAB-Mass, TG–DTA data and ESR spectral studies were used to confirm the structures of the complexes. Electronic absorption and IR spectra of the complexes suggest a square-planar geometry around the central metal ion. The interaction of complexes with pET30a plasmid DNA was investigated by spectroscopic measurements. Results suggest that the copper complexes bind to DNA via an intercalative mode and can quench the fluorescence intensity of EB bound to DNA. The interaction between the complexes and DNA has also been investigated by agarose gel electrophoresis, interestingly, we found that the copper(II) complexes can cleave circular plasmid DNA to nicked and linear forms.Cu(II) complexes of Thio-Schiff bases have been synthesized and characterized using different techniques. The interaction of the complexes with DNA gives interesting results and the complexes also have ability to cleave DNA.► Two Cu(II) complex bases have been synthesized and characterized using different techniques. ► The molecular geometry of one of these ligands has been determined by single crystal X-ray study. ► The interaction of complexes with DNA was investigated by spectroscopic and viscometric methods. ► The DNA cleavage of the complexes has also been investigated by submarine gel electrophoresis.
International Journal of Biological Macromolecules, 2011
The interaction of a copper complexes containing Schiff bases with calf thymus (CT) DNA was investigated by spectroscopic methods. UV-vis, fluorescence and CD spectroscopies were conducted to assess their binding ability with CT DNA. The binding constants K have been estimated from 0.8 to 9.1 × 10 4 M −1 . The percentage of hypochromism is found to be over 70% (from spectral titrations). The results showed that the copper(II) complexes could bind to DNA with an intercalative mode. Synergic action of Cu(II) complexes with ascorbic acid against Candida albicans induced the generation of free radicals and increased (more than 60 times) antimicrobial effect of these complexes.
Journal of Photochemistry and Photobiology B: Biology, 2011
New Schiff base ligand L derived from the condensation reaction of 2-amino-3-formylchromone with (R)-2-amino-2-phenylethanol was synthesized and characterized which involves combination element of ammine functionality and naturally occurring heterocyclic chromone, 4H-benzopyran-4-one. Subsequently, their complexes 1 and 2 with Cu(NO 3 ) 2 and Zn(NO 3 ) 2 , respectively were prepared. The DNA binding studies of the ligand L and complexes 1 and 2 with CT-DNA as compared to classical anticancer drug cisplatin were carried out by employing different optical methods viz, UV-vis, fluorescence, circular dichroism and viscosity measurements. Furthermore, the absorption studies, 1 H and 31 P with mononucleotides were also monitored to examine the base specific interactions of the transition metal complexes which revealed a higher propensity of copper(II) complex 1 for 5 0 -GMP while for zinc(II) complex 2 towards 5 0 -TMP involving groove binding mechanism of the complexes towards DNA. The complex 1 exhibits a remarkable DNA cleavage activity with pBR322 DNA in presence of different activators and cleavage reaction involves various oxygen species suggesting the involvement of active oxygen species for the DNA scission.
Nucleosides, Nucleotides & Nucleic Acids, 2018
Azo linked salicyldehyde and a new 2-hydroxy acetophenone based ligands (HL 1 and HL 2) with their copper(II) complexes [Cu(L 1) 2 ] (1) and [Cu(L 2) 2 ] (2) were synthesized and characterized by spectroscopic methods such as 1 H, 13C NMR, UV-Vis spectroscopy and elemental analyses. Calculation based on Density Functional Theory (DFT), have been performed to obtain optimized structures. Binding studies of these copper (II) complexes with calf thymus DNA (ct-DNA) and torula yeast RNA (t-RNA) were analyzed by absorption spectra, emission spectra and Viscosity studies and Molecular Docking techniques. The absorption spectral study indicated that the copper(II) complexes of 1 and 2 had intrinsic binding constants with DNA or RNA in the range of 7.6 ± 0.2 Â 10 3 M 21 or 6.5 ± 0.3 Â 10 3 M 21 and 5.7 ± 0.4 Â 10 4 M 21 or 1.8 ± 0.5 Â 10 3 M 21 respectively. The synthesized compounds and nucleic acids were simulated by molecular docking to explore more details mode of interaction of the complexes and their orientations in the active site of the receptor.