research article synthesis and characterisation of copper...

Research ArticleSynthesis and Characterisation of Copper(II) Complexeswith Tridentate NNO Functionalized Ligand DensityFunction Theory Study DNA Binding Mechanism OpticalProperties and Biological Application

Madhumita Hazra12 Tanushree Dolai1 Akhil Pandey3

Subrata Kumar Dey2 and Animesh Patra1

1 Postgraduate Department of Chemistry Midnapore College Midnapore 721101 India2Department of Chemistry Sidho-Kanho-Birsha University Purulia West Bengal 723101 India3 Department of Microbiology Midnapore College Midnapore 721101 India

Correspondence should be addressed to Subrata Kumar Dey skdjuchemyahoocom andAnimesh Patra animeshpatrarlyahoocom

Received 29 May 2014 Revised 2 August 2014 Accepted 14 August 2014 Published 16 October 2014

Academic Editor Guillermo Mendoza-Diaz

Copyright copy 2014 Madhumita Hazra et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

The photo physical properties of two mononuclear pentacoordinated copper(II) complexes formulated as [Cu(L)(Cl)(H2O)] (1)

and [Cu(L)(Br)(H2O)] (2)HL= (1-[(3-methyl-pyridine-2-ylimino)-methyl]-naphthalen-2-ol) were synthesized and characterized

by elemental physicochemical and spectroscopic methods The density function theory calculations are used to investigate theelectronic structures and the electronic properties of ligand and complex The interactions of copper(II) complexes towards calfthymus DNA were examined with the help of absorption viscosity and fluorescence spectroscopic techniques at pH 740 Allspectroscopyrsquos result indicates that complexes show good binding activity to calf thymus DNA through groove binding Theoptical absorption and fluorescence emission properties of microwires were characterized by fluorescence microscope From aspectroscopic viewpoint all compounds strongly emit green light in the solid state The microscopy investigation suggested thatmicrowires exhibited optical waveguide behaviour which are applicable as fluorescent nanomaterials and can be used as buildingblocks for miniaturized photonic devices Antibacterial study reveals that complexes are better antimicrobial agents than free Schiffbase due to bacterial cell penetration by chelation Moreover the antioxidant study of the ligand and complexes is evaluated byusing 11-diphenyl-2-picrylhydrazyl (DPPH) free-radical assays which demonstrate that the complexes are of higher antioxidantactivity than free ligand

1 Introduction

Copper(II) complexes play an important role in the activesites of a large number of metalloproteins in biologicalsystems and potential application for numerous catalyticprocesses in living organisms that involve electron transferreactions or activation of some antitumor substances [1]These processes are also involved inbioinorganic [2] andmedicinal chemistry [3] In fact copper(II) chelates havebeen found to interact with biological systems and to exhibit

antineoplastic activity [4ndash6] and antibacterial antifungal [78] and anticancer activity [9] Some copper(II) NSONN-donor chelators are good anticancer agents due to strongbinding ability with DNA base pair [10] Pyridines are com-mon but vital heterocyclic compounds in organic synthesisespecially as agrochemicals and synthetic intermediates Forexample pyridine derivatives such as (aromatic) alkoxylpyridine compounds amidopyridine and its derivatives sub-stituted fused pyridine compounds have already been widelyapplied in the fields of agrochemical products [11] Moreover

Hindawi Publishing CorporationBioinorganic Chemistry and ApplicationsVolume 2014 Article ID 104046 13 pageshttpdxdoiorg1011552014104046

2 Bioinorganic Chemistry and Applications

N

CHO

N N CH

HO

OH

EtOH3-Methyl-2-aminopyridine2-Hydroxy-1-naphthaldehyde

(1-[(3-Methyl-pyridine-2-ylimino)-methyl]-naphthalen-2-ol)

HL

HL

1

2MeOHReflux4h

NH2

CuCl2[Cu(L)(Cl)(H2O)]

CuBr2 [Cu(L)(Br)(H2O)]

+

MeOHReflux4h

Reflux3h

Scheme 1 Synthetic procedure of the ligand and its copper(II) complexes

pyridine derivatives play a unique role in anthelminthic aca-ricide bacteriocide and phytocide [12] For these biologicaleffects we choose the pyridine derivative ligand as a startingmaterial

DNA biopolymer plays essential role in the growthdevelopment and heritage transmission of living species notonly of humans and animals but also of the vegetal onesThisis one of the most important substances in biological systemwhose base pairs carrying the genetic information relatednot only to the normal life activity but also to the abnormalactivities such as carcinogenesis Compounds having abilityto bind and cleave double stranded DNA under physiologicalconditions are of importance for their utility as diagnosticagents in medicinal applications and for genomic researchDNA base pairs and amino sugar moiety are involved mainlyin intercalative or groove binding interactions In this respectthe design of functional materials has received consider-able attention due to their propensity to take part also inpotential applications in DNAmolecule probes [13] Fluores-cence spectroscopy measurement also helps in studying thedynamic interactions and apparition of macromolecules andmacromolecular complexes The relevance of fluorescencetechniques to a range of bioanalytical biophysical assaysis based on the use of different fluorescence probes thatcan interact with macromolecules and with nucleic acids(DNA and RNA) The applications of DNA in photonics andoptoelectronics have attracted intensive attentions during

recent years [14] because the DNA-lipid complex has thermaland optical stability [15]

Herein we report an account of fluorescent mononuclearcopper(II) complexes obtained with tridentate NNO-donor ligand (1-[(3-methyl-pyridine-2-ylimino)-methyl]-naphthalen-2-ol) (HL) (vide Scheme 1)The electron transfermechanism of copper(II) complexes is investigated by cyclicvoltammetry The density function theory calculations areused to examine the electronic properties of these complexesTheDNAbinding study of the copper(II) complexes has beenperformed spectroscopically Here we report the synthesisof new copper complexes nanowires with DNA and explainfluorescence emission properties From a spectroscopicstudy copper(II) complexes strongly emit green light in thesolid state DNA optical microwire devices are expectedto be used as optical biosensors The antioxidant studyof the ligand and complexes is evaluated by using DPPHfree-radical assays Antibacterial activity of the Schiff baseand its copper complexes has also been studied by agar discdiffusionmethod against some species of pathogenic bacteria(Escherichia coli Vibrio cholerae Streptococcus pneumoniaand Bacillus cereus)

2 Materials and Physical Measurements

All chemicals and reagents were obtained from commercialsources and used as received unless otherwise stated Sol-vents were distilled from an appropriate drying agent The

Bioinorganic Chemistry and Applications 3

organic moieties were synthesized following the procedureThe elemental (C H N) analyses were performed on a PerkinElmer model 2400 elemental analyzer Copper analysis wascarried out by Varian atomic absorption spectrophotometer(AAS) model-AA55B GTA using graphite furnace Elec-tronic absorption spectra were recorded on a SHIMADZUUV-1800 spectrophotometer The fluorescence spectra of EBbound to DNA were obtained in the fluorimeter (Hitachi-2000) Electron spray ionization (ESI) mass spectra wererecorded on a QtofMicro YA263mass spectrometer IR spec-tra (KBr discs 4000ndash400 cmminus1) were recorded using a PerkinElmer FTIRmodel RX1 spectrometerThe room temperaturemagnetic susceptibility measurements were performed byusing a vibrating sample magnetometer PAR 155 modelMolar conductance (ΛM) was measured in a systronicsconductivity meter 304 model using sim10minus3mol Lminus1 solutionsin DMF solvent Optical microscopy images were takenusing an NIKON ECLIPSE LV100POL upright microscopeequipped with a 12V-50W halogen lamp The samples foroptical microscopic study were prepared by placing a dropof colloidal solution onto a clean glass slide Electrochemicalmeasurements were performed using computer-controlledCH-Instruments (Model No CHI620D) All measurementswere carried out under nitrogen environment at 298K withreference to SCE electrode in dimethyl formamide using[119899-Bu

4N]ClO

4as supporting electrolyte Stock solutions of

complex-1 and complex-2 were prepared in DMF because oftheir lower solubility in water

21 Preparation of the Ligand (HL) The synthesis of ligandHL was prepared by modifying the reported procedure [16]An ethanolic solution of 2-hydroxy-naphthaldehyde (086 g50mmol) was added to 3-methyl-2-aminopyridine (064 g50mmol) in ethanol Then this mixture was allowed to stirat room temperature for 2 h and then it was refluxed for 3 hThe mixture was cooled to room temperature and kept overone night to get the precipitate of the solid orange ligandThe precipitate was filtered by using vacuum pump andwashed several times using ethanol to remove any unreactedmaterials then product was collected by recrystallizationfrom ethanol and dried in vacuum desiccators Finally theproduct was characterized by IR 1H NMR and 13C NMRspectroscopy

C17H14N2O anal FoundC 7786H 534N 1068 Calc

C 7782 H 528 N 1044 mp 186 plusmn 1∘C IR (KBr cmminus1)VOndashH 3448 VC=N 1472 VCH=N 1623

1H NMR (120575 ppm inCDCl

3+ CCl

4) 15686 (d 1Ha) 9976 (d 1Hb) 830 (d 1Hc)

689 (d 1Hd) 815ndash704 (m 9H) 2498 (s 1He)13C NMR

14908 (C-9) 14631 (C-1) 13945 (C-7) 12932ndash11931 (Ar-C)1700 (C-6) yield 90

22 Preparation of [Cu(L)(Cl)(H2O)] (1) and [Cu(L)

(Br)(H2O)] (2) To prepare the copper(II) complexes (1

and 2) a common procedure (Scheme 1) was followed asdescribed below using copper(II) chloride for complex(1) copper(II) bromide (2) and the organic ligand (HL)in equimolar (1 1) ratio A methanolic solution of HL(10mmol) was mixed with 10mmol of copper(II) chloride

(1) and copper(II) bromide (2) with stirring condition andthe mixture was refluxed for 4 h The solid product wascollected by filtration and washing with cold methanol andwater then dried in vacuo The pure crystallized product wasobtained from methanol

[Cu(L)(Cl)(H2O)] (1) yield 80ndash85 C

17H15N2O2CuCl

Complex-1 C17H15N2O2CuCl Anal Found C 5396 H

396 N 740 Cu 1681 Calc C 5384 H 392 N 734 Cu1672 IR (cmminus1) VCH=N 1618 VC=N 1470 VOndashH 3438 mp 232plusmn 1∘C ESIMS (119898119911)M+ 378 [M+2]+ 380Magneticmoment(120583 BM) 174 Conductivity (Λo S cmminus1) in DMF 632

[Cu(L)(Br)(H2O)] (2) yield 75ndash80 C

17H15N2O2CuBr

Complex-2 C17H15N2O2CuBr Anal Found C 4829 H

355 N 662 Cu 1503 Calc C 4818 H 348 N 654 Cu1482 IR (cmminus1) VCH=N 1620 VC=N 1468 VOndashH 3440mp 243plusmn 1∘C ESIMS (119898119911) M+ 422 [M+2]+ 424 Magnetic moment(120583 BM) 172 Conductivity (Λo S cmminus1) in DMF 630

23TheoreticalMethodology Allmolecular calculationswereperformed in the gas phase using density functional theory(DFT) with B3 [17] LYP [18] with [1] exchange correlationfunctional The basis set 6-31G (d p) was used for all atoms[19] All calculations were carried out using the GAUSSIAN09 program package with the aid of the Gauss View visualiza-tion program [20]

24 DNA Binding Experiments The DNA binding experi-ments were done by a Tris-HCl buffer (pH 74) with coppercomplexes in DMF solvent The DNA concentration pernucleotide was determined by absorption spectroscopy usingthe molar absorption coefficient (6600 (mol Lminus1)minus1 cmminus1) at260 nm A solution of DNA in the buffer gave a ratio of UVabsorbance at 260 and 280 nm of about 18-19 indicatingthat the DNAwas sufficiently free of protein [21] Absorptionspectral titration experiment was performed by keepingthe constant concentration of the copper(II) complex andvarying the CT-DNA concentration After addition of DNAto the copper complex the resulting solution was allowed toequilibrate at 25∘C for 30min after which absorption spectrawere noted

Ethidium bromide displays very weak fluorescence inaqueous solution However in the presence of DNA itexhibits intense fluorescence because of the intercalation tobase pairs in DNA In the ethidium bromide (EB) fluores-cence displacement experiment 5120583L of the EB Tris-HClsolution (1mmol Lminus1) was added to 1mL of DNA solution[22] stored in the dark for 2 h Then the solution of thecopper(II) complex was titrated into the DNAEB mixtureand diluted in Tris-HCl buffer to 5mL to get the solutionwith the appropriate complexCT-DNA mole ratio Prior tomeasurements the mixture was shaken up and incubated atroom temperature for 30min Fluorescence measurementswere performed at an excitation wavelength of 522 nm andthe emitted fluorescence was analyzed at 610 nm

25 Determination of Viscosity Viscosity experiments wereconducted on an Ostwaldrsquos viscometer The concentrationof the copper(II) complexes (1 and 2) varying from 05 to


Table 1 UV-Vis spectral and electrochemical data of complex-1 and complex-2

Compound UV-Vis data 120582 nm (120576 dm3 molminus1 cmminus1)a Electrochemical dataa

119864pc (V) 119864pa (V) 11986412

(V)1 262 (10532) 319 (8037) 365 (3125) 667 (236) minus0779 minus0602 minus06902 254 (9753) 327 (6534) 362 (2176) 672 (154) minus0712 minus0597 minus0654aIn DMF electrochemical data recorded in mV at 298K and scan rate 100mVsminus1 11986412 = (119864pc + 119864pa)2

40 times 10minus6M and each complex was introduced into a DNAsolution (525 times 10minus6M) present in the viscometer Eachsample was measured two times and average flow time wascalculated The values of relative viscosities of DNA in theabsence and presence of the complexes are plotted against theratio of the concentration of complex and CT-DNA [23]

26 Antimicrobial Screening The antibacterial activity ofthe tested samples was determined using a modified agardisc diffusion method [24] The activities were done at 100and 200120583gmL concentrations of ligand and its copper(II)complexes in DMF solvent by using three pathogenic Gramnegative bacteria (Escherichia coli Vibrio cholerae and Strep-tococcus pneumoniae) and one Gram positive pathogenicbacteria (Bacillus cereus) The solution of ligand and itscopper(II) complexes were added to the agar plates andincubation of the plates was done at 37∘C for 24 hours At theend of the period the diameter of the inhibition zones wascalculated in millimetres [25]

27 DPPH Radical Scavenging Activity Antioxidant activ-ity of the synthesized compounds was estimated by 11-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effectThe 01mL of different concentrations (25 to 150 120583gmL) ofsample in methanol was added to 4mL of a 146 times 10minus5MDPPH solution and then solution was left to stand at roomtemperature in the dark After 30min of incubation theabsorbance of the solution was measured at 520 nm [26]

28 Synthesis and Characterization The organic ligand (HL= (1-[(3-methyl-pyridine-2-ylimino)-methyl]-naphthalen-2-ol)) was synthesized by the reaction of the respective 3-methyl-2-aminopyridine (5mmol) and then 50mmol of2-hydroxy-1-naphthaldehyde in presence of ethanol Thecomplexes were obtained in good yield from the reactionof the copper chloride (1) and copper bromide (2) withequimolar amount of organic moiety HL in the methanolmedium In these complexes the organic moleculeHL acts astridentate ligand throughNNOdonor centresThe complexesconductivity measurement in DMF suggests that complexesexist in solution as nonelectrolytes [27] These complexesare air-stable coloured solids partly soluble in ethanol andmethanol and soluble in acetonitrile DMSO and DMF Allcopper(II) complexes are nonhygroscopic andmonomeric innature At room temperature the magnetic moments (120583) ofthese complexes are 174 and 172 BM Satisfactory analyticalresults were obtained for all the complexes exhibiting para-magnetic character comparable to mononuclear copper(II)complexes of tridentate Schiff bases [28] From conductivity

UV-Vis spectra andmagnetic momentmeasurement indicateall complexes are distorted trigonal bipyramidal geometry[29]

29 Infrared and Electronic Spectral Studies The IR spectrumof the ligand has several bands appearing at 3448 1472and 1623 cmminus1 due to phenolic OndashH group pyridine C=Nand imine CH=N stretching vibrations in the solid state(see Figure S1 in Supplementary Material available online athttpdxdoiorg1011552014104046) The hydroxyl hydro-gen of ligand is replaced by a metal in metal complexesIn complexation the bands are shifted to lower frequencyat 409ndash411 and 514ndash518 cmminus1 which are attributed to theexistence of CundashOandCundashNbondwith copper(II) ionThesevibrations confirmed the involvement of nitrogen and oxygenatom in chelation with metal ion Hence a broad band in therange of 3438ndash3440 cmminus1 indicates the presence of a watermolecule in complex-1 and complex-2 All the IR data suggestthat the metal ions are coordinated to the Schiff base throughthe phenolic oxygen imino-nitrogen and pyridine nitrogenand with one water molecule

The proton NMR spectra of the free ligand have beenrecorded in CDCl

3at room temperature using CCl

4as an

internal standard (Figure S2) The ligand exhibits hydroxylproton (Ha) appearing at 120575 1568 ppm the aromatic pyridineproton (Hb) appearing at 120575 997 ppm Hc appearing at 120575830 ppm Hd appearing at 120575 689 ppm methyl proton (He)appearing at 120575 249 ppm and aromatic and heteroaromaticproton signals appearing at 120575 704ndash815 ppm The chemicalshift of hydroxyl proton is very high (1568 ppm) indicatingintramolecular hydrogen bond (inset Figure S2) 13C NMRspectra (Figure S3) showed similar diagnostic features for thefree ligand Hydroxyl carbon (C-9) was found at 14908 ppmpyridine carbon (C-1) at 14631 ppm and imine carbon (C-7) at 13945 ppm and the methyl carbon (C-6) signal wasfound at 170 ppm and aromatic carbons were found at 1193ndash1293 ppm NMR spectra of the free ligand support theconclusions derived from the IR spectra

The electronic spectra of all complexes were recorded inDMF at room temperature The electronic spectral data ofthe Schiff base and their complexes are given in Table 1 Allthe spectra of complexes show lower bands than 400 nm dueto 120587 rarr 120587lowast and 119899 rarr 120587lowast transitions for the aromatic ringand again absorption bands at 4360 nm and 456 nm are dueto intraligand charge transfer transitions An intense band at262 nm is assigned to 120587 rarr 120587lowast intraligand transition [30]along with the less intense bands at 319 and 365 nm corre-sponding to the ligand tometal charge transfer transitionThecopper(II) complex-1 and complex-2 show a dndashd broad and


a weak band centered at 664 and 672 nm which is attributedto 2B1g rarr

2A1g transition [31] This electronic spectrum is

compared with five coordinate complexes consistent with thedegree of distortion from the TBP geometry [29 32]

210 Electron Sprays Ionization Mass Spectra (ESI MS) Themass spectra of complexes (Figures S4 and S5) support theirprojected formulation It reveals the molecular ion peak119898119911 at 26216 consistent with the molecular weight of theligand whereas its copper complexes (1 and 2) show a weakmolecular ion peak at119898119911 37814 and 4226 due to the higherinstability A weak peak at 119898119911 380 and 424 corresponds tothe [M+2]+ peak possibly due to the presence of isotopicchlorine and bromine in the copper complexes of 1 and 2respectively [33 34] Other peaks were observed at 119898119911 361324 248 and 161 which corresponds to different fragmentsthat support the structure of the copper complexes

211 Electrochemistry The redox properties of the Cu(II)complexes were examined by cyclic voltammetry using aPt-disk working electrode and a Pt-wire auxiliary electrodein dry dimethylformamide using [119899-Bu

4N]ClO

4(01M) as

the supporting electrolyte The cyclic voltammetric data aregiven in Table 1 The cyclic voltammograms exhibit quasi-reversible electron transfer process with a reduction peak at119864pc = minus0779V andminus0712Vwith a corresponding oxidationpeak at 119864pa = minus0602V and minus0597V for complex-1 andcomplex-2 respectively at a scan rate interval 50ndash400mV sminus1The 119864

12values for these Cu(II)Cu(I) redox couples were

in the range of minus0690 to minus0654V versus AgAgCl and theratio of cathodic to anodic peak height was less than oneThe most significant feature of the Cu(II) complexes are theCu(II)Cu(I) couple [35]The ratio between the cathodic peakcurrent and the square root of the scan rate (119868pcV

12) isapproximately constant From this cyclic voltammetry data itcan be deduced that the redox couples are related to a quasi-reversible one-electron transfer process

212 Emission Activity The emission property of the ligandHL and its copper(II) complexes was recorded at roomtemperature (298K) in 1 times 10minus6 (M) DMF solution given inFigure 1 In the absence of metal ions the fluorescence of theligand is probably quenched by the occurrence of a photoinduced electron transfer (PET) process due to the presenceof lone pair of electrons in the ligand [36] It is evident thatthe fluorescence emission intensity of the ligand decreasesdramatically depending on the complex formation with themetal ions These coordination complexes make the energytransfer from the excited state of the ligand to the metalions causing decreases of the fluorescence intensity For thisreason the intensity of complex-1 and complex-2 is decreasedThe ligand shows higher fluorescence intensity at 352 nmwhile complex-2 is fluorescence silent when both are excitedat 300 nm in DMF solution

213 Electronic Structure Full geometry optimization of HLand copper(II) complexes (1 and 2) was carried out using

350 400 4500

500

1000

1500

2000

2500

3000

Wavelength (nm)

Emiss

ion

inte

nsity

Complex-1HLComplex-2

Figure 1 Fluorescence emission properties of the free ligand (HL)and its copper(II) complexes

density functional theory (DFT) at the B3LYP level in theirground state shown in Figure 2 The frontier orbitals ofHOMO and LUMO of HL 1 and 2 are also given in Figure 2The selected bond distances and bond angles are reported inTable S1 Thus it is apparent that electron density of HOMOin HL is largely localized on both pyridine and naphthalenering HOMO of copper(II) complexes have largely localizedon pyridine ring and partly on naphthalene but in LUMOelectrons are largely localized on naphthalene ring TheHOMO-LUMO energy gap in the ground state of complex-1and complex-2 has been predicted to be 00212 and 00139 eVrespectively and is not influenced by excitation From thisoptimized structure the bond length of CundashCl is 216 A andof CundashBr is 229 A this suggests that larger size of bromineatom forms weaker overlap with copper atom but other bondlengths are comparable The N1ndashC1ndashN2 bond angle of HL is11930∘ but on complex formation the bond angle decreases to8536∘ and 8613∘ for 1 and 2 respectively

214 DNA Binding Studies The binding interaction of thecopper(II) complexeswith calf thymusDNAhas been investi-gated with the help of spectroscopic viscosity measurementsand electrochemical study

215 Electronic Absorption Study In general the hyper-chromism and hypochromism were regarded as spectralfeatures for DNA double-helix structural change when DNAreacted with other moleculesThe hyperchromism originatesfrom the breakage of the DNA duplex secondary structurethe hypochromism originates from the stabilization of theDNA duplex by either the intercalation binding mode or theelectrostatic effect of small moleculesIt is reported that if the


HO

MO

LUM

OO

ptim

ized

Complex-1 HL Complex-2

E = minus10 eV E = minus01904 eV E = minus02323 eV

E = 00 eV E = minus01692 eV E = minus02184 eV

C1C2C3

C4 C5

C6C7

C8

C9C10 C11

C12C13

C14C15C16

C17

N1N1 N1

N2N2 N2

O1

O1 O1O2 O2

Cl

Cu Cu

Br

Figure 2 The HOMO and LUMO orbitals of HL and copper(II) complex-1 and complex-2 obtained from DFT

aromatic ring of themolecule closelymatches with the helicalturn of the CT-DNA groove the aromatic rings of the ligandinteract with DNA in Tris-HCl buffer through the formationof the van der Waals contacts or hydrogen bonds in the DNAgrooves The binding of the copper(II) complex to the CT-DNA helix is examined by an increase of the absorptionband (ca 264 nm) of copper(II) complex This increasingabsorbance indicates that there is the involvement of stronginteractions between complex and the base pairs ofDNA [37]The absorption spectra of the copper(II) complexes in theabsence and presence of CT-DNA are shown in Figure 3 Ahyperchromism was also observed for a copper(II) complexwith a ligand bearing minusOH group The extent of the hyper-chromism in the charge transfer band is generally consistentwith the strength of interaction [38] As DNA double helixpossesses many hydrogen bonding sites which are accessibleboth in the minor and in the major grooves it is likely thatthe ndashOHgroup of the ternary complex forms hydrogen bondswith DNA which may contribute to the hyperchromismobserved in absorption spectra The increasing absorbanceindicates there is groove binding modes

In order to further illustrate the binding strength ofthe copper(II) complex with CT-DNA the intrinsic binding

constant 119870119887was determined from the spectral titration data

using the following equation [39]

[DNA](120576119886minus 120576119891)

=[DNA](120576119886minus 120576119891)

+1

[119870119887(120576119887minus 120576119891)]

(1)

where [DNA] is the concentration of DNA 120576119891 120576119886 and 120576

119887

correspond to the extinction coefficient respectively for thefree copper(II) complex for each addition of DNA to thecopper(II) complex and for the copper(II) complex in thefully bound form The [DNA](120576

119886minus 120576119891) plot against [DNA]

gave a linear relationship shown in Figure 3 The intrinsicbinding constants (119870

119887) for the complexes were calculated

from the slope to intercept ratio The 119870119887value for complex-

1 and complex-2 was estimated to be 608 times 104Mminus1 (119877 =099025 up to five points) and 598 times 104Mminus1 (119877 = 09881 upto five points) in terms of groove binding These values arein agreement with those of well-established groove bindingrather than classical intercalation [40]

Again DNA binding interaction is compared with thepresence of ligand with CT-DNA From absorption spectrathere is no change in absorption spectral band upon increas-ing the DNA concentration This absorbance indicates that


250 300 350 400 450 50000

05

10

15

20

25

f

a

Abso

rban

ce

Wavelength (nm)

(a)

250 300 350 400 450 50000

05

10

15

20

25

f

a

Abso

rban

ce

Wavelength (nm)

(b)

0 2 4 6 8 1014

16

18

20

22

24

[DNA] times10minus6

[DN

A](120576

aminus120576 b)times10

minus9

(c)

0 2 4 6 8 10

16

18

20

22

24

[DNA] times10minus6

[DN

A](120576


minus9

(d)

Figure 3 Electronic spectral titration (a b) of complex-1 (a) and complex-2 (b) with CT-DNA at 266 nm in Tris-HCl buffer [complex] =234 times 10minus5 [DNA] a 00 b 122 times 10minus6 c 244 times 10minus6 d 366 times 10minus6 e 488 times 10minus6 f 610 times 10minus6mol Lminus1 The arrow denotes the gradual increaseof DNA concentration Plot of [DNA](120576

119886minus 120576119891) versus [DNA] for the absorption titration of CT-DNA with the copper(II) complex-1 (c) and

complex-2 (d) in Tris-HCl buffer at the (c d)

there is no involvement of interactions between ligand andthe base pairs of DNA

216 Ethidium Bromide Fluorescence Displacement Experi-ments Fluorescence quenching is a helpful method to studythe reactivity of chemical and biological systems since itallows nonintrusive dimensions of substances in low con-centration under physiological circumstances [41] usefulinformation about binding mechanisms and providing cluesto the nature of binding Fluorescence intensity of a com-pound can be quenched as a result of molecular interactionssuch as excited state reactions molecular rearrangementsground state complex formation and collisional quenchingFluorescence intensity of EB bound to CT-DNA shows adecreasing trend with the increasing concentration of thecomplexes as shown in Figure 4The quenching of EB bound

to DNA by the complexesis in agreement with the linearStern-Volmer equation [42]

1198680

119868= 1 + 119870sv [119876] (2)

where 1198680and 119868 represent the fluorescence intensities in the

absence and presence of quencher respectively119870sv is a linearStern-Volmer quenching constant and119876 is the concentrationof quencher The 119870sv value calculated from the plot is shownin Figure 4 of 119868

0119868 versus [complex] The value of Stern-

Volmer quenching constant (119870sv) was 194 times 104 (119877 = 098576

up to four points) and 134 times 104 (119877 = 098818 up to fourpoints) for complex-1 and complex-2 respectively The 119870svvalue in fluorescence spectral studies indicates the noninter-calative binding interaction with DNA and probable groovebinding or external binding is suggested for complex-1 and


600 650 700 7500

200

400

600

800

1000

1200

h

a

Inte

nsity

Wavelength (nm)

(a)

575 600 625 650 675 7000

200

400

600

800

1000

1200

a

h

Inte

nsity

Wavelength (nm)

(b)

05 10 15 20 25 3012

16

20

24

28

32

[Complex] times 10minus6

I 0I

(c)

05 10 15 20 25 30 35 4010

12

14

16

18

20


I 0I

(d)

Figure 4 Emission spectra (a b) of the CT-DNA-EB system in Tris-HCl buffer upon the titration of the copper(II) complex-1 (a) andcomplex-2 (b) 120582ex = 522 nm [EB] = 92 times 10minus6mol Lminus1 [DNA] = 122 times 10minus6 [complex] a 00 b 136 times 10minus5 c 272 times 10minus5 d 408 times 10minus5 e 544times 10minus5 f 680 times 10minus5 g 816 times 10minus5 h 952 times 10minus5mol Lminus1 Arrow shows the intensity change upon the increase of the complex concentrationPlot of 119868

119900119868 against [complex] in fluorescence quenching of CT-DNA-EB system in Tris-HCL buffer (c d) complex-1 (c) and complex-2 (d)

respectively

complex-2 which is supported by viscosity measurementsThus the binding interaction is groove binding mode butnot involved in intercalative binding All the Stern-Volmerplots represent a good linear relationship indicating a strongaffinity of the copper(II) complexes to CT-DNA

217 Binding Parameters When small molecules bind inde-pendently to a set of equivalent sites on a macromolecule thebinding constant (119870

119887) and the numbers of binding sites (119899)

can be determined using the following equation [43]

log[(1198680minus 119868)

119868] = log119870

119887+ 119899 log [119876] (3)

119870119887and 119899 are the binding constant and binding site of

complex-1 and complex-2 to CT-DNA respectively Thenumber of binding sites (119899) is determined from the interceptof log[(119868

0minus 119868)119868] versus log[119876] The number of binding

sites (119899) is 093 and 089 for complex-1 and complex-2respectively The result indicates less association of complex-1 and complex-2 to the DNA bases also suggesting strongaffinity of the complexes through surface or groove binding

218 Cyclic Voltammetric Studies Electrochemical measure-ment is a most constructive technique to analyse metal-DNA interactions than spectroscopic methods [44] Theelectrochemical investigations of metal-DNA interactionscan provide a useful complement to spectroscopic methods


minus12minus10minus08minus06minus04minus0200

00

12 times 10minus5

60 times 10minus6

minus60 times 10minus6

Curr

ent (

A)

Potential (V)

(a) (b)

Figure 5 Cyclic voltammograms of complex-1 in Tris-HCl buffer inthe absence (a) and presence (b) of CT-DNA v = 1V sminus1

which inform about interactions with both the reducedand oxidized form of the metal Electrochemical studiesof transition-metal complexes have been extensive and theeffect of ligand concentration on potential can be used todetermine formation constants In the absence of DNAthe complexes show sharp waves peaks for both oxidationand reduction state Upon addition of DNA both wavesrsquopeaks of 119868pc and 119868pa are decreased due to large bindingof copper(II) complexes to DNA and not to an increasein solution viscosity we performed CV experiments on amixture of copper(II) complex which intercalates betweenthe DNA base pairs In this study it has been employedto recognize the nature of DNA binding of the copper(II)complexes and the result is given in Figure 5 This resultindicated that interaction occurs between the CT-DNA andcopper(II) complexes The equilibrium binding constants1198701198771198700can be calculated by using the shift value of the formal

potential (Δ1198640) of Cu(II)Cu(I) according to the Bard andCarter equation [45]

Δ1198640= 1198640

119887minus 1198640

119891= 00591 log(

119870119877

1198700

) (4)

where 1198640119887and 1198640

119891are the formal potentials of the bound

and free complex forms respectively and 119870119877and 119870

0are the

corresponding binding constants for the binding of reductionand oxidation species to DNA respectively The ratio ofequilibriumbinding constants119870

1198771198700 is calculated to be 243

and 209 for complex-1 and complex-2 respectively whichindicate the strong binding of DNA with reduced form overoxidised form of copper complexes

219 Effect of CT-DNA on Viscosity Measurements Con-sidering the nature of DNA binding of the complexes wecarried out viscosity measurements on CT-DNA by varyingthe concentration of added complexes Hydrodynamic mea-surements such as viscosity and sedimentation are criticaltests for a binding mode in solution in the absence of crystal-lographic structural data [46] Because DNA viscosities are

020 025 030 035 040 045 050 05503

04

05

06

07

08

[ComplexDNA]

Complex-1EBComplex-2

(120578120578

0)13

Figure 6 Effect of increasing amounts of copper(II) complexes (1and 2) on the relative viscosity of CT-DNA at 25∘C

sensitive to the length changes of nucleic acids a classicalintercalation mode should result in lengthening the DNAhelix as base pairs are separated to accommodate the bindingligand or the nonclassical intercalation could bend or kinkthe DNA helix thereby decreasing its length and viscosityFrom the viscosity measurements it was observed that thereis no change in the relative viscosity of the DNA solutionby increasing the concentration of adding complex givenin Figure 6 However complex-1 and complex-2 block theintercalative interaction strongly and hence the negligiblechanges in the relative DNA viscosity observed This is inconformity with its lowest DNA binding affinity Similarlythe presence of hydroxyl group on the naphthyl ring wouldalso sterically hinder the partial insertion of the ligand ring inbetween the DNA base pairs leading to no change in relativeviscosity of DNAThis suggests that these complexes interactwith CT-DNA through groove binding mode

220 Fluorescence Microscopy Study of Cu-DNA Com-plexes The fluorescence micrograph showed formation ofmicrowires shaped copper complex with DNA (Figure 7)The obtained green microwires were characterized by usingfluorescence microscopy to investigate their optical waveg-uide properties The fluorescence micrograph was obtainedby the excitation of the sample with blue light between 450and 490 nm (Scheme 2) This investigation clearly demon-strates that Cu complexes (1 and 2) molecules have beenincorporated into the DNA microparticles and arbitrarilydistributed in the nanoparticles This leads to an impressiveincrease in the fluorescence intensity of the polymer even onhigh dilution with DNA During the formation of the dopedmicroparticles hydrophobic and 120587-120587 interactions induce theaggregation of DNA and Cu complexes (1 and 2) moleculesinto microparticles [47] This clarification suggested that the


(a) (b)

(c) (d)

Figure 7 Optical and fluorescence micrographs of complex-1 (a and b) and complex-2 (c and d) with DNA microwires respectively Thefluorescence micrograph was obtained by the excitation of the sample with blue light between 450 and 490 nm

Copper complex- 1 andcomplex-2

∙ Blue colour complex

Optical microscope image

∙ Mixing with DNA∙ Blue light excitation

Fluorescence microscopeimage∙ Mixing with DNA∙ Green emission

Scheme 2 Synthetic route of fluorescent green microwires of complex-1 and complex-2 with DNA

microwires absorbed the excitation light and propagated thefluorescence emission toward the tips thereby exhibitingstrong wave guiding behaviour The DNA-Cu complexesmicrowires show significant optical waveguide properties dueto the strong fluorescence emission

221 Antibacterial Activity Antibacterial activity of the lig-and and its copper(II) complexes is tabulated in Figure 8The biological activity of the synthesized ligand and itscompounds are compared with standard antibiotic chlo-ramphenicol drug From this study it is inferred that allcomplexes have higher activity than ligand but lower thanantibiotic Here height of the bar represents the activity ofcomplexes and ligand with respect to standard antibioticTheincreased activity of the metal chelates can be explained by

overtone concept and the Tweedy chelation theory [48] Thevariation in the activity of copper(II) complexes against somedifferent organisms depends on either the impermeabilityof the cells of the microbes [49] or difference in ribosomeof microbial cells and also activity increases with increasingthe concentration of complexes In a complex polarity ofmetal ions reduces due to partial sharing of its positive chargewith donor groups of ligand and delocalization of 120587-electroninto the whole chelate ring Lipids and polysaccharidesare important constituents of cell walls and membraneswhich are preferred for metal ion interaction This increasedlipophilicity also helps the penetration of the bacterial cellmembranes and restricts further growth of the microorgan-isms Due to higher lipophilicity complex-1 and complex-2exhibit higher antibacterial activity than free ligand


0

5

10

15

20

25

30

35

40

E coli V cholerae B cereus S pneumonia

HL1

2Chloramphenicol

100120583gmL

0

10

20

30

40

50

60

70


HL1

2Chloramphenicol

200120583gmL

Figure 8 Comparison of the antibacterial activity of HL complex-1 and complex-2with standard chloramphenicol drug DMF solvent doesnot show any activity

Table 2 Antioxidant activity (120583M) of ligand and metal complexes (1 and 2) at different concentrations using DPPH assay

Compounds Concentration (120583gmL)0 25 50 75 100 125 150

AA 0 998 2024 2964 4084 4723 5457HL 0 757 1354 2065 2687 3298 3643Complex-1 0 852 1587 2576 3482 4174 4732Complex-2 0 812 1623 2376 3367 3912 4318

222 Antioxidant Activity We investigated the free radicalscavenging ability of the newly synthesized ligand and itscomplexes using DPPHTheDPPH radical is one of the mostcommonly used substrates for fast evaluation of antioxidantactivity because of its stability and simplicity of the assayIn DPPH assay the ligand and its complexes act as donorsof hydrogen atoms or electrons in transformation of DPPHradical into its reduced form DPPH-H The breaking of theOH bond is considered to be one of the most importantphysicochemical parameters involved in the definition of theantioxidant potency of phenolic derivatives [50] Phenolsare also excellent chain-breaking antioxidants and good 1O

2

quenchers [51] Lower absorbance values of the reactionmixture indicated higher free radical scavenging activityThe DPPH radical scavenging ability of the ligands andtheir complexes is shown in Table 2 It is inferred thatfree radical scavenging activities of synthesized compoundsare concentration dependent and the activity of complexesincreases with increasing its concentration Ascorbic acid aphenolic antioxidant used as a standard showed strongerantioxidant activity than that of synthesized compounds Itcan be concluded that complexes aremore scavenging activitythan ligand due to partial sharing of positive charge withhole organic moiety and also electron releasing hydroxyland methyl group present in the ligand moiety After thecomplexation with metal ions reveals that the antioxidantactivity increases due to the presence of positively chargedmeal ions as well as electron donating groups present in the

moiety so complexes have a strong potential to be applied asscavengers to eliminate radicals [52]

3 Conclusion

Synthesis and characterization of two mononuclear cop-per(II) complexes of N

2O donor set have been per-

formed All complexes are pentacoordinated formulated as[Cu(L)(Cl)(H

2O)] (1) and [Cu(L)(Br)(H

2O)] (2)The electro-

chemical study of these complexes showed a quasi-reversibleone-electron transfer process DNA binding properties ofthe copper(II) complexes with DNA have been investigatedby absorption spectra fluorescence spectra and voltamme-try measurements All results indicate that the copper(II)complexes bind to CT-DNA via groove binding modeComplexation between the copper complexes (1 and 2) andthe anionic DNA molecules appears to stiffen the backbonesof the former leading to a green color in its fluorescenceemission The observed enhancement of fluorescence maybe utilized in sensing DNA DFT calculations are used toobserve the electronic structure and the electronic propertiesof copper(II) complexes Furthermore in vitro antioxidantactivity of copper(II) complexes also exhibits the effectivescavenging of DPPH radicals In addition the result ofantibacterial studies confirmed that ligand and complexesare bioactive showing good antimicrobial property It hasalso been proposed that concentration plays a vital role in


increasing the degree of inhibition as the concentrationincreases the activity increases

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

The authors are thankful to Professor Pabitra ChattopadhyayDepartment of Chemistry Burdwan University for his moralsupport encouragement and guidance

References

[1] A Chakraborty P Kumar K Ghosh and P Roy ldquoEvaluation ofa Schiff base copper complex compound as potent anticancermolecule with multiple targets of actionrdquo European Journal ofPharmacology vol 647 no 1ndash3 pp 1ndash12 2010

[2] R H Holm P Kennepohl and E I Solomon ldquoStructural andfunctional aspects of metal sites in biologyrdquo Chemical Reviewsvol 96 no 7 pp 2239ndash2314 1996

[3] M A Ali C M Haroon M Nazimuddin S M M-UMajumder M T H Tarafder and M A Khair ldquoSynthesischaracterization andbiological activities of somenewnickel(II)copper(II) zinc(II) and cadmium(II) complexes of quadriden-tate SNNS ligandsrdquoTransitionMetal Chemistry vol 17 no 2 pp133ndash136 1992

[4] D T Minkel C H Chanstier and D H Petering ldquoReactions of3-Ethoxy-2-oxobutyraldehyde Bis(N4-dimethylthiosemicarba-zonato)-Zinc(II) with tumor cells andmitochondriardquoMolecularPharmacology vol 12 no 6 pp 1036ndash1044 1976

[5] V Rajendiran R Karthik M Palaniandavar et al ldquoMixed-ligand copper(II)-phenolate complexes effect of coligand onenhanced DNA and protein binding DNA cleavage and anti-cancer activityrdquo Inorganic Chemistry vol 46 no 20 pp 8208ndash8221 2007

[6] A E Liberta and D XWest ldquoAntifungal and antitumor activityof heterocyclic thiosemicarbazones and their metal complexescurrent statusrdquo Biometals vol 5 no 2 pp 121ndash126 1992

[7] Y Harinath D H K Reddy B N Kumar C Apparao and KSeshaiah ldquoSynthesis spectral characterization and antioxidantactivity studies of a bidentate Schiff base 5-methyl thiophene-2-carboxaldehyde-carbohydrazone and its Cd(II) Cu(II) Ni(II)and Zn(II) complexesrdquo Spectrochimica Acta Part A Molecularand Biomolecular Spectroscopy vol 101 pp 264ndash272 2013

[8] J Sheikh H Juneja V Ingle P Ali and T B Hadda ldquoSynthesisand in vitro biology of Co(II) Ni(II) Cu(II) and Zinc(II) com-plexes of functionalized beta-diketone bearing energy buriedpotential antibacterial and antiviral OO pharmacophore sitesrdquoJournal of Saudi Chemical Society vol 17 no 3 pp 269ndash2762013

[9] C Marzano M Pellei F Tisato and C Santini ldquoCopper com-plexes as anticancer agentsrdquo Anti-Cancer Agents in MedicinalChemistry vol 9 no 2 pp 185ndash211 2009

[10] S M Saadeh ldquoSynthesis characterization and biological prop-erties of Co(II) Ni(II) Cu(II) and Zn(II) complexes with anSNO functionalized ligandrdquo Arabian Journal of Chemistry vol6 no 2 pp 191ndash196 2013

[11] J Garcıa-Tojal A Garcıa-Orad A A Dıaz et al ldquoBiologicalactivity of complexes derived from pyridine-2-carbaldehydethiosemicarbazone structure of [Co(C

7H7N4S)2][NCS]rdquo Jour-

nal of Inorganic Biochemistry vol 84 no 3-4 pp 271ndash278 2001[12] P R Reddy and A Shilpa ldquo2-hydroxynaphthalene-1-

carbaldehyde- and 2-aminomethyl)pyridine-based Schiffbase Cu119868119868 complexes for DNA binding and cleavagerdquo Chemistryamp Biodiversity vol 9 no 10 pp 2262ndash2281 2012

[13] N ShahabadiMM Khodaei S Kashanian and F KheirdooshldquoInteraction of a copper (II) complex containing an artificialsweetener (aspartame) with calf thymus DNArdquo SpectrochimicaActa Part A Molecular and Biomolecular Spectroscopy vol 120pp 1ndash6 2014

[14] A J Steckl ldquoDNAmdasha new material for photonicsrdquo NaturePhotonics vol 1 pp 3ndash5 2007

[15] S Bandyopadhyay M Tarek and M L Klein ldquoMoleculardynamics study of a lipid-DNA complexrdquo The Journal ofPhysical Chemistry B vol 103 no 46 pp 10075ndash10080 1999

[16] M Hazra T Dolai A Pandey S K Dey and A Patra ldquoFluo-rescent copper(II) complexes the electron transfer mechanisminteraction with bovine serum albumin (BSA) and antibacterialactivityrdquo Journal of Saudi Chemical Society 2014

[17] A D Becke ldquoDensityminusfunctional thermochemistry III Therole of exact exchangerdquoThe Journal of Chemical Physics vol 98article 5648 1993

[18] C Lee W Yang and R G Parr ldquoDevelopment of the Colle-Salvetti correlation-energy formula into a functional of theelectron densityrdquo Physical Review B vol 37 no 2 pp 785ndash7891998

[19] S Roy T K Mondal P Mitra E L Torres and C Sinha ldquoSyn-thesis structure spectroscopic properties electrochemistryand DFT correlative studies of N-[(2-pyridyl)methyliden]-6-coumarin complexes of Cu(I) and Ag(I)rdquo Polyhedron vol 30no 6 pp 913ndash922 2011

[20] J A PopleM J FrischGWTrucks et alGaussian 09 RevisionB01 Gaussian Wallingford UK 2009

[21] M E Reichman S A Rice C A Tgomas and P DotyldquoA further examination of the molecular weight and Size ofdesoxypentose nucleic acidrdquo Journal of the American ChemicalSociety vol 76 no 11 pp 3047ndash3053 1954

[22] A Patra B Sen S Sarkar A Pandey E Zangrando andP Chattopadhyay ldquoNickel(II) complexes with 2-(pyridin-3-ylmethylsulfanyl)phenylamine and halidepseudohalides Syn-thesis structural characterisation interaction with CT-DNAand bovine serum albumin and antibacterial activityrdquo Polyhe-dron vol 51 no 1 pp 156ndash163 2013

[23] D Lahiri T Bhowmick B Pathak et al ldquoAnaerobic photo-cleavage of DNA in red light by dicopper(II) complexes of 331015840-dithiodipropionic acidrdquo Inorganic Chemistry vol 48 no 1 pp339ndash349 2009

[24] C Sheikh M S Hossain M S Easmin M S Islam andM Rashid ldquoEvaluation of in vitro antimicrobial and in vivocytotoxic properties of somenovel titanium-based coordinationcomplexesrdquo Biological and Pharmaceutical Bulletin vol 27 no5 pp 710ndash713 2004

[25] J Singh andP Singh ldquoSynthesis spectroscopic characterizationand in vitro antimicrobial studies of pyridine-2-carboxylic acidN1015840-(4-chloro-benzoyl)-hydrazide and its Co(II) Ni(II) andCu(II) complexesrdquo Bioinorganic Chemistry and Applicationsvol 2012 Article ID 104549 7 pages 2012


[26] H Wu J Yuan Y Bai et al ldquoSynthesis structure DNA-binding properties and antioxidant activity of silver(i) com-plexes containing V-shaped bis-benzimidazole ligandsrdquo DaltonTransactions vol 41 no 29 pp 8829ndash8838 2012

[27] S Dey T Mukherjee S Sarkar H S Evans and PChattopadhyay ldquo5-Nitro-110-phenanthroline bis(NN-pyridylmethylthio-Κ1015840O)- bis(perchlorato) copper(II)synthesis structural characterization and DNA-bindingstudyrdquo Transition Metal Chemistry vol 36 no 6 pp 631ndash6362011

[28] M Valko R Boca R Klement et al ldquoEffect of hydrogenationon electronic and distant magnetic properties in copper(II)complexes with derivatives of tetrahydrosalen and salen X-raycrystal structure of [CuBuMe(saltmen)] complexrdquo Polyhedronvol 16 pp 903ndash908 1997

[29] S Dey S Sarkar H Paul E Zangrando and P ChattopadhyayldquoCopper(II) complex with tridentate N donor ligand synthesiscrystal structure reactivity and DNA binding studyrdquo Polyhe-dron vol 29 no 6 pp 1583ndash1587 2010

[30] B H Chen H H Yao W T Huang P Chattopadhyay J MLo and T H Lu ldquoSyntheses and molecular structures of threeCu(II) complexes with tetradentate imine-phenolsrdquo Solid StateSciences vol 1 no 2-3 pp 119ndash131 1999

[31] A B P Lever Inorganic Electronic Spectroscopy Elsevier Ams-terdam The Netherlands 2nd edition 1984

[32] S Sarkar A Patra M G B Drew E Zangrando and PChattopadhyay ldquoCopper(II) complexes of tetradentate N2S2donor sets synthesis crystal structure characterization andreactivityrdquo Polyhedron vol 28 no 1 pp 1ndash6 2009

[33] W Kemp Organic Spectroscopy Macmillan Press New YorkNY USA 1975

[34] R A Sheikh S Shreaz G S Sharma L A Khan andA A Hashmi ldquoSynthesis characterization and antimicro-bial screening of a novel organylborate ligand potassiumhydro(phthalyl)(salicylyl)borate and its Co(II) Ni(II) andCu(II) complexesrdquo Journal of Saudi Chemical Society vol 16 no4 pp 353ndash361 2012

[35] A D Kulkarni S A Patil and P S Badami ldquoElectrochemicalproperties of some transition metal complexes synthesis char-acterization and in-vitro antimicrobial studies of Co(II) Ni(II)Cu(II) Mn(II) and Fe(III) complexesrdquo International Journal ofElectrochemical Science vol 4 pp 717ndash729 2009

[36] S Konar A Jana K Das et al ldquoSynthesis crystal struc-ture spectroscopic and photoluminescence studies of man-ganese(II) cobalt(II) cadmium(II) zinc(II) and copper(II)complexes with a pyrazole derived Schiff base ligandrdquo Polyhe-dron vol 30 no 17 pp 2801ndash2808 2011

[37] A Patra S Sen S Sarkar E Zangrando and P Chattopad-hyay ldquoSyntheses crystal structures and DNAbinding of somenickel(II) complexes of 13-bis(2-pyridylmethylthio)propaneand pseudohalidesrdquo Journal of Coordination Chemistry vol 65no 23 pp 4096ndash4107 2012

[38] N Lingthoingambi N Rajen Singh and M Damayanti ldquoDNAinteraction and biological activities of Copper(II) complexes ofalkylamidio-O-methylureardquo Journal of Chemical and Pharma-ceutical Research vol 3 no 6 pp 187ndash194 2011

[39] A Patra S Sarkar T Mukherjee E Zangrando and P Chat-topadhyay ldquoZinc(II) complexes of 13-bis(2-pyridylmethyl-thio)propane anion dependency crystal structure and DNAbinding studyrdquo Polyhedron vol 30 no 17 pp 2783ndash2789 2011

[40] R Sinha M M Islam K Bhadra G S Kumar A Banerjeeand M Maiti ldquoThe binding of DNA intercalating and non-intercalating compounds to A-form and protonated form ofpoly(rC)sdotpoly(rG) spectroscopic and viscometric studyrdquo Bioor-ganic amp Medicinal Chemistry vol 14 no 3 pp 800ndash814 2006

[41] R Indumathy S Radhika M Kanthimathi T Weyhermullerand BUnniNair ldquoCobalt complexes of terpyridine ligand crys-tal structure and photocleavage of DNArdquo Journal of InorganicBiochemistry vol 101 no 3 pp 434ndash443 2007

[42] O Stern and M Volmer ldquoUber die abklingungszeit der fluo-reszenz (The extinction period of fluorescence)rdquo PhysikalischeZeitschrift vol 20 pp 183ndash188 1919

[43] A Kathiravan and R Renganathan ldquoPhotoinduced interactionsbetween colloidal TiO

2nanoparticles and calf thymus-DNArdquo

Polyhedron vol 28 no 7 pp 1374ndash1378 2009[44] S Mahadevan and M Palaniandavar ldquoSpectroscopic and

voltammetric studies on copper complexes of 29-dimethyl-110-phenanthrolines bound to calf thymus DNArdquo InorganicChemistry vol 37 no 4 pp 693ndash700 1998

[45] M T Carter and A J Bard ldquoVoltammetric studies of theinteraction of tris(110-phenanthroline)cobalt(III) with DNArdquoJournal of the American Chemical Society vol 109 no 24 pp7528ndash7530 1987

[46] S Satyanarayana J C Dabrowiak and J B ChairesldquoTris(phenanthroline)ruthenium(II) enantiomer interactionswith DNA mode and specificity of bindingrdquo Biochemistry vol32 no 10 pp 2573ndash2584 1993

[47] A I Dragan R Pavlovic J B McGivney et al ldquoSYBR Green Ifluorescence properties and interaction with DNArdquo Journal ofFluorescence vol 22 no 4 pp 1189ndash1199 2012

[48] J Joseph K Nagashri and G A B Rani ldquoSynthesis characteri-zation and antimicrobial activities of copper complexes derivedfrom 4-aminoantipyrine derivativesrdquo Journal of Saudi ChemicalSociety vol 17 no 3 pp 285ndash294 2013

[49] S A Patil V H Naik A D Kulkarni and P S BadamildquoDNA cleavage antimicrobial spectroscopic and fluorescencestudies of Co(II) Ni(II) and Cu(II) complexes with SNO donorcoumarin Schiff basesrdquo Spectrochimica ActamdashPart A Molecularand Biomolecular Spectroscopy vol 75 no 1 pp 347ndash354 2010

[50] S B Bukhari S Memon M Mahroof-Tahir andM I BhangerldquoSynthesis characterization and antioxidant activity copper-quercetin complexrdquo Spectrochimica Acta A Molecular andBiomolecular Spectroscopy vol 71 no 5 pp 1901ndash1906 2009

[51] B Stefan F Susanne and E Hansgeorg ldquoCarotenylflavonoidsa novel group of potent dual-functional antioxidantsrdquo Arkivocvol 8 pp 279ndash295 2007

[52] K Konarikova L Andrezalova P Rapta et al ldquoEffect ofthe Schiff base complex diaqua-(N-salicylidene-l-glutamato)copper(II) monohydrate on human tumor cellsrdquo EuropeanJournal of Pharmacology vol 721 no 1ndash3 pp 178ndash184 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


N

CHO

N N CH

HO

OH

EtOH3-Methyl-2-aminopyridine2-Hydroxy-1-naphthaldehyde

(1-[(3-Methyl-pyridine-2-ylimino)-methyl]-naphthalen-2-ol)

HL

HL

1

2MeOHReflux4h

NH2

CuCl2[Cu(L)(Cl)(H2O)]

CuBr2 [Cu(L)(Br)(H2O)]

+

MeOHReflux4h

Reflux3h

Scheme 1 Synthetic procedure of the ligand and its copper(II) complexes

pyridine derivatives play a unique role in anthelminthic aca-ricide bacteriocide and phytocide [12] For these biologicaleffects we choose the pyridine derivative ligand as a startingmaterial

DNA biopolymer plays essential role in the growthdevelopment and heritage transmission of living species notonly of humans and animals but also of the vegetal onesThisis one of the most important substances in biological systemwhose base pairs carrying the genetic information relatednot only to the normal life activity but also to the abnormalactivities such as carcinogenesis Compounds having abilityto bind and cleave double stranded DNA under physiologicalconditions are of importance for their utility as diagnosticagents in medicinal applications and for genomic researchDNA base pairs and amino sugar moiety are involved mainlyin intercalative or groove binding interactions In this respectthe design of functional materials has received consider-able attention due to their propensity to take part also inpotential applications in DNAmolecule probes [13] Fluores-cence spectroscopy measurement also helps in studying thedynamic interactions and apparition of macromolecules andmacromolecular complexes The relevance of fluorescencetechniques to a range of bioanalytical biophysical assaysis based on the use of different fluorescence probes thatcan interact with macromolecules and with nucleic acids(DNA and RNA) The applications of DNA in photonics andoptoelectronics have attracted intensive attentions during

recent years [14] because the DNA-lipid complex has thermaland optical stability [15]

Herein we report an account of fluorescent mononuclearcopper(II) complexes obtained with tridentate NNO-donor ligand (1-[(3-methyl-pyridine-2-ylimino)-methyl]-naphthalen-2-ol) (HL) (vide Scheme 1)The electron transfermechanism of copper(II) complexes is investigated by cyclicvoltammetry The density function theory calculations areused to examine the electronic properties of these complexesTheDNAbinding study of the copper(II) complexes has beenperformed spectroscopically Here we report the synthesisof new copper complexes nanowires with DNA and explainfluorescence emission properties From a spectroscopicstudy copper(II) complexes strongly emit green light in thesolid state DNA optical microwire devices are expectedto be used as optical biosensors The antioxidant studyof the ligand and complexes is evaluated by using DPPHfree-radical assays Antibacterial activity of the Schiff baseand its copper complexes has also been studied by agar discdiffusionmethod against some species of pathogenic bacteria(Escherichia coli Vibrio cholerae Streptococcus pneumoniaand Bacillus cereus)

2 Materials and Physical Measurements

All chemicals and reagents were obtained from commercialsources and used as received unless otherwise stated Sol-vents were distilled from an appropriate drying agent The



4N]ClO







3+ CCl

4) 15686 (d 1Ha) 9976 (d 1Hb) 830 (d 1Hc)








17H15N2O2CuCl




17H15N2O2CuBr










119864pc (V) 119864pa (V) 11986412










4as an









4N]ClO

4(01M) as







350 400 4500

500

1000

1500

2000

2500

3000

Wavelength (nm)

Emiss

ion

inte

nsity







HO

MO

LUM

OO

ptim

ized




C1C2C3

C4 C5

C6C7

C8

C9C10 C11

C12C13

C14C15C16

C17

N1N1 N1

N2N2 N2

O1

O1 O1O2 O2

Cl

Cu Cu

Br






[DNA](120576119886minus 120576119891)

=[DNA](120576119886minus 120576119891)

+1

[119870119887(120576119887minus 120576119891)]

(1)


119887









250 300 350 400 450 50000

05

10

15

20

25

f

a

Abso

rban

ce

Wavelength (nm)

(a)

250 300 350 400 450 50000

05

10

15

20

25

f

a

Abso

rban

ce

Wavelength (nm)

(b)

0 2 4 6 8 1014

16

18

20

22

24

[DNA] times10minus6

[DN

A](120576


minus9

(c)

0 2 4 6 8 10

16

18

20

22

24

[DNA] times10minus6

[DN

A](120576


minus9

(d)







1198680

119868= 1 + 119870sv [119876] (2)







600 650 700 7500

200

400

600

800

1000

1200

h

a

Inte

nsity

Wavelength (nm)

(a)

575 600 625 650 675 7000

200

400

600

800

1000

1200

a

h

Inte

nsity

Wavelength (nm)

(b)

05 10 15 20 25 3012

16

20

24

28

32


I 0I

(c)

05 10 15 20 25 30 35 4010

12

14

16

18

20


I 0I

(d)



respectively





log[(1198680minus 119868)

119868] = log119870

119887+ 119899 log [119876] (3)








00

12 times 10minus5

60 times 10minus6


Curr

ent (

A)

Potential (V)

(a) (b)




Δ1198640= 1198640

119887minus 1198640

119891= 00591 log(

119870119877

1198700

) (4)

where 1198640119887and 1198640



0are the





020 025 030 035 040 045 050 05503

04

05

06

07

08

[ComplexDNA]


(120578120578

0)13





(a) (b)

(c) (d)












0

5

10

15

20

25

30

35

40


HL1

2Chloramphenicol

100120583gmL

0

10

20

30

40

50

60

70


HL1

2Chloramphenicol

200120583gmL






2



3 Conclusion











Acknowledgment


References



































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



4N]ClO







3+ CCl

4) 15686 (d 1Ha) 9976 (d 1Hb) 830 (d 1Hc)








17H15N2O2CuCl




17H15N2O2CuBr










119864pc (V) 119864pa (V) 11986412










4as an









4N]ClO

4(01M) as







350 400 4500

500

1000

1500

2000

2500

3000

Wavelength (nm)

Emiss

ion

inte

nsity







HO

MO

LUM

OO

ptim

ized




C1C2C3

C4 C5

C6C7

C8

C9C10 C11

C12C13

C14C15C16

C17

N1N1 N1

N2N2 N2

O1

O1 O1O2 O2

Cl

Cu Cu

Br






[DNA](120576119886minus 120576119891)

=[DNA](120576119886minus 120576119891)

+1

[119870119887(120576119887minus 120576119891)]

(1)


119887









250 300 350 400 450 50000

05

10

15

20

25

f

a

Abso

rban

ce

Wavelength (nm)

(a)

250 300 350 400 450 50000

05

10

15

20

25

f

a

Abso

rban

ce

Wavelength (nm)

(b)

0 2 4 6 8 1014

16

18

20

22

24

[DNA] times10minus6

[DN

A](120576


minus9

(c)

0 2 4 6 8 10

16

18

20

22

24

[DNA] times10minus6

[DN

A](120576


minus9

(d)







1198680

119868= 1 + 119870sv [119876] (2)







600 650 700 7500

200

400

600

800

1000

1200

h

a

Inte

nsity

Wavelength (nm)

(a)

575 600 625 650 675 7000

200

400

600

800

1000

1200

a

h

Inte

nsity

Wavelength (nm)

(b)

05 10 15 20 25 3012

16

20

24

28

32


I 0I

(c)

05 10 15 20 25 30 35 4010

12

14

16

18

20


I 0I

(d)



respectively





log[(1198680minus 119868)

119868] = log119870

119887+ 119899 log [119876] (3)








00

12 times 10minus5

60 times 10minus6


Curr

ent (

A)

Potential (V)

(a) (b)




Δ1198640= 1198640

119887minus 1198640

119891= 00591 log(

119870119877

1198700

) (4)

where 1198640119887and 1198640



0are the





020 025 030 035 040 045 050 05503

04

05

06

07

08

[ComplexDNA]


(120578120578

0)13





(a) (b)

(c) (d)












0

5

10

15

20

25

30

35

40


HL1

2Chloramphenicol

100120583gmL

0

10

20

30

40

50

60

70


HL1

2Chloramphenicol

200120583gmL






2



3 Conclusion











Acknowledgment


References



































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




119864pc (V) 119864pa (V) 11986412










4as an









4N]ClO

4(01M) as







350 400 4500

500

1000

1500

2000

2500

3000

Wavelength (nm)

Emiss

ion

inte

nsity







HO

MO

LUM

OO

ptim

ized




C1C2C3

C4 C5

C6C7

C8

C9C10 C11

C12C13

C14C15C16

C17

N1N1 N1

N2N2 N2

O1

O1 O1O2 O2

Cl

Cu Cu

Br






[DNA](120576119886minus 120576119891)

=[DNA](120576119886minus 120576119891)

+1

[119870119887(120576119887minus 120576119891)]

(1)


119887









250 300 350 400 450 50000

05

10

15

20

25

f

a

Abso

rban

ce

Wavelength (nm)

(a)

250 300 350 400 450 50000

05

10

15

20

25

f

a

Abso

rban

ce

Wavelength (nm)

(b)

0 2 4 6 8 1014

16

18

20

22

24

[DNA] times10minus6

[DN

A](120576


minus9

(c)

0 2 4 6 8 10

16

18

20

22

24

[DNA] times10minus6

[DN

A](120576


minus9

(d)







1198680

119868= 1 + 119870sv [119876] (2)







600 650 700 7500

200

400

600

800

1000

1200

h

a

Inte

nsity

Wavelength (nm)

(a)

575 600 625 650 675 7000

200

400

600

800

1000

1200

a

h

Inte

nsity

Wavelength (nm)

(b)

05 10 15 20 25 3012

16

20

24

28

32


I 0I

(c)

05 10 15 20 25 30 35 4010

12

14

16

18

20


I 0I

(d)



respectively





log[(1198680minus 119868)

119868] = log119870

119887+ 119899 log [119876] (3)








00

12 times 10minus5

60 times 10minus6


Curr

ent (

A)

Potential (V)

(a) (b)




Δ1198640= 1198640

119887minus 1198640

119891= 00591 log(

119870119877

1198700

) (4)

where 1198640119887and 1198640



0are the





020 025 030 035 040 045 050 05503

04

05

06

07

08

[ComplexDNA]


(120578120578

0)13





(a) (b)

(c) (d)












0

5

10

15

20

25

30

35

40


HL1

2Chloramphenicol

100120583gmL

0

10

20

30

40

50

60

70


HL1

2Chloramphenicol

200120583gmL






2



3 Conclusion











Acknowledgment


References



































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of







4N]ClO

4(01M) as







350 400 4500

500

1000

1500

2000

2500

3000

Wavelength (nm)

Emiss

ion

inte

nsity







HO

MO

LUM

OO

ptim

ized




C1C2C3

C4 C5

C6C7

C8

C9C10 C11

C12C13

C14C15C16

C17

N1N1 N1

N2N2 N2

O1

O1 O1O2 O2

Cl

Cu Cu

Br






[DNA](120576119886minus 120576119891)

=[DNA](120576119886minus 120576119891)

+1

[119870119887(120576119887minus 120576119891)]

(1)


119887









250 300 350 400 450 50000

05

10

15

20

25

f

a

Abso

rban

ce

Wavelength (nm)

(a)

250 300 350 400 450 50000

05

10

15

20

25

f

a

Abso

rban

ce

Wavelength (nm)

(b)

0 2 4 6 8 1014

16

18

20

22

24

[DNA] times10minus6

[DN

A](120576


minus9

(c)

0 2 4 6 8 10

16

18

20

22

24

[DNA] times10minus6

[DN

A](120576


minus9

(d)







1198680

119868= 1 + 119870sv [119876] (2)







600 650 700 7500

200

400

600

800

1000

1200

h

a

Inte

nsity

Wavelength (nm)

(a)

575 600 625 650 675 7000

200

400

600

800

1000

1200

a

h

Inte

nsity

Wavelength (nm)

(b)

05 10 15 20 25 3012

16

20

24

28

32


I 0I

(c)

05 10 15 20 25 30 35 4010

12

14

16

18

20


I 0I

(d)



respectively





log[(1198680minus 119868)

119868] = log119870

119887+ 119899 log [119876] (3)








00

12 times 10minus5

60 times 10minus6


Curr

ent (

A)

Potential (V)

(a) (b)




Δ1198640= 1198640

119887minus 1198640

119891= 00591 log(

119870119877

1198700

) (4)

where 1198640119887and 1198640



0are the





020 025 030 035 040 045 050 05503

04

05

06

07

08

[ComplexDNA]


(120578120578

0)13





(a) (b)

(c) (d)












0

5

10

15

20

25

30

35

40


HL1

2Chloramphenicol

100120583gmL

0

10

20

30

40

50

60

70


HL1

2Chloramphenicol

200120583gmL






2



3 Conclusion











Acknowledgment


References



































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


HO

MO

LUM

OO

ptim

ized




C1C2C3

C4 C5

C6C7

C8

C9C10 C11

C12C13

C14C15C16

C17

N1N1 N1

N2N2 N2

O1

O1 O1O2 O2

Cl

Cu Cu

Br






[DNA](120576119886minus 120576119891)

=[DNA](120576119886minus 120576119891)

+1

[119870119887(120576119887minus 120576119891)]

(1)


119887









250 300 350 400 450 50000

05

10

15

20

25

f

a

Abso

rban

ce

Wavelength (nm)

(a)

250 300 350 400 450 50000

05

10

15

20

25

f

a

Abso

rban

ce

Wavelength (nm)

(b)

0 2 4 6 8 1014

16

18

20

22

24

[DNA] times10minus6

[DN

A](120576


minus9

(c)

0 2 4 6 8 10

16

18

20

22

24

[DNA] times10minus6

[DN

A](120576


minus9

(d)







1198680

119868= 1 + 119870sv [119876] (2)







600 650 700 7500

200

400

600

800

1000

1200

h

a

Inte

nsity

Wavelength (nm)

(a)

575 600 625 650 675 7000

200

400

600

800

1000

1200

a

h

Inte

nsity

Wavelength (nm)

(b)

05 10 15 20 25 3012

16

20

24

28

32


I 0I

(c)

05 10 15 20 25 30 35 4010

12

14

16

18

20


I 0I

(d)



respectively





log[(1198680minus 119868)

119868] = log119870

119887+ 119899 log [119876] (3)








00

12 times 10minus5

60 times 10minus6


Curr

ent (

A)

Potential (V)

(a) (b)




Δ1198640= 1198640

119887minus 1198640

119891= 00591 log(

119870119877

1198700

) (4)

where 1198640119887and 1198640



0are the





020 025 030 035 040 045 050 05503

04

05

06

07

08

[ComplexDNA]


(120578120578

0)13





(a) (b)

(c) (d)












0

5

10

15

20

25

30

35

40


HL1

2Chloramphenicol

100120583gmL

0

10

20

30

40

50

60

70


HL1

2Chloramphenicol

200120583gmL






2



3 Conclusion











Acknowledgment


References



































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


250 300 350 400 450 50000

05

10

15

20

25

f

a

Abso

rban

ce

Wavelength (nm)

(a)

250 300 350 400 450 50000

05

10

15

20

25

f

a

Abso

rban

ce

Wavelength (nm)

(b)

0 2 4 6 8 1014

16

18

20

22

24

[DNA] times10minus6

[DN

A](120576


minus9

(c)

0 2 4 6 8 10

16

18

20

22

24

[DNA] times10minus6

[DN

A](120576


minus9

(d)







1198680

119868= 1 + 119870sv [119876] (2)







600 650 700 7500

200

400

600

800

1000

1200

h

a

Inte

nsity

Wavelength (nm)

(a)

575 600 625 650 675 7000

200

400

600

800

1000

1200

a

h

Inte

nsity

Wavelength (nm)

(b)

05 10 15 20 25 3012

16

20

24

28

32


I 0I

(c)

05 10 15 20 25 30 35 4010

12

14

16

18

20


I 0I

(d)



respectively





log[(1198680minus 119868)

119868] = log119870

119887+ 119899 log [119876] (3)








00

12 times 10minus5

60 times 10minus6


Curr

ent (

A)

Potential (V)

(a) (b)




Δ1198640= 1198640

119887minus 1198640

119891= 00591 log(

119870119877

1198700

) (4)

where 1198640119887and 1198640



0are the





020 025 030 035 040 045 050 05503

04

05

06

07

08

[ComplexDNA]


(120578120578

0)13





(a) (b)

(c) (d)












0

5

10

15

20

25

30

35

40


HL1

2Chloramphenicol

100120583gmL

0

10

20

30

40

50

60

70


HL1

2Chloramphenicol

200120583gmL






2



3 Conclusion











Acknowledgment


References



































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


600 650 700 7500

200

400

600

800

1000

1200

h

a

Inte

nsity

Wavelength (nm)

(a)

575 600 625 650 675 7000

200

400

600

800

1000

1200

a

h

Inte

nsity

Wavelength (nm)

(b)

05 10 15 20 25 3012

16

20

24

28

32


I 0I

(c)

05 10 15 20 25 30 35 4010

12

14

16

18

20


I 0I

(d)



respectively





log[(1198680minus 119868)

119868] = log119870

119887+ 119899 log [119876] (3)








00

12 times 10minus5

60 times 10minus6


Curr

ent (

A)

Potential (V)

(a) (b)




Δ1198640= 1198640

119887minus 1198640

119891= 00591 log(

119870119877

1198700

) (4)

where 1198640119887and 1198640



0are the





020 025 030 035 040 045 050 05503

04

05

06

07

08

[ComplexDNA]


(120578120578

0)13





(a) (b)

(c) (d)












0

5

10

15

20

25

30

35

40


HL1

2Chloramphenicol

100120583gmL

0

10

20

30

40

50

60

70


HL1

2Chloramphenicol

200120583gmL






2



3 Conclusion











Acknowledgment


References



































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



00

12 times 10minus5

60 times 10minus6


Curr

ent (

A)

Potential (V)

(a) (b)




Δ1198640= 1198640

119887minus 1198640

119891= 00591 log(

119870119877

1198700

) (4)

where 1198640119887and 1198640



0are the





020 025 030 035 040 045 050 05503

04

05

06

07

08

[ComplexDNA]


(120578120578

0)13





(a) (b)

(c) (d)












0

5

10

15

20

25

30

35

40


HL1

2Chloramphenicol

100120583gmL

0

10

20

30

40

50

60

70


HL1

2Chloramphenicol

200120583gmL






2



3 Conclusion











Acknowledgment


References



































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


(a) (b)

(c) (d)












0

5

10

15

20

25

30

35

40


HL1

2Chloramphenicol

100120583gmL

0

10

20

30

40

50

60

70


HL1

2Chloramphenicol

200120583gmL






2



3 Conclusion











Acknowledgment


References



































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


0

5

10

15

20

25

30

35

40


HL1

2Chloramphenicol

100120583gmL

0

10

20

30

40

50

60

70


HL1

2Chloramphenicol

200120583gmL






2



3 Conclusion











Acknowledgment


References



































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





Acknowledgment


References



































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of








































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

research article synthesis and characterisation of copper...

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