Mixed Ligand Complexes of N-Methyl-N-phenyl Dithiocarbamate ...

Research ArticleMixed Ligand Complexes of N-Methyl-N-phenylDithiocarbamate Synthesis Characterisation AntifungalActivity and Solvent Extraction Studies of the Ligand

Anthony C Ekennia1 Damian C Onwudiwe23 Cyril Ume4 and Eno E Ebenso23

1Department of Chemistry Federal University Ndufu-Alike Ikwo PMB 1010 Abakaliki Ebonyi Nigeria2Material Science Innovation and Modelling (MaSIM) Research Focus Area Faculty of Agriculture Science and TechnologyNorth-West University (Mafikeng Campus) Private Bag X2046 Mmabatho South Africa3Department of Chemistry School of Mathematical and Physical Sciences Faculty of Agriculture Science and TechnologyNorth-West University (Mafikeng Campus) Private Bag X2046 Mmabatho 2735 South Africa4Department of Chemical Engineering Federal University Ndufu-Alike Ikwo PMB 1010 Abakaliki Ebonyi Nigeria

Correspondence should be addressed to Damian C Onwudiwe dcconwudiwegmailcom

Received 7 July 2015 Revised 26 August 2015 Accepted 30 August 2015

Academic Editor Spyros P Perlepes

Copyright copy 2015 Anthony C Ekennia 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

A series of mixed ligand dithiocarbamate complexes with a general formula [ML2(py)2] where M = Mn(II) Co(II) Ni(II) and

Cu(II) py = pyridine and L = N-methyl-N-phenyl dithiocarbamate have been prepared and characterised by elemental analysisFTIR and Uv spectroscopy magnetic moment and thermogravimetric and conductance analysis The infrared spectra showedthat symmetrical bidentate coordination occurred with the dithiocarbamate moiety through the sulfur atoms while neutralmonodentate coordination occurred through the nitrogen atom for the pyridine molecule in the complexesThe electronic spectraelemental analysis and magnetic moment results proved that the complexes adopted octahedral geometry The conductancemeasurement showed that the complexes are nonelectrolytes proving their nonionic nature The compounds were screened forthree human pathogenic fungi Aspergillus flavus Aspergillus niger and Candida albicans The cobalt complex showed the bestantifungal activity among the test compounds Liquid-liquid extractive abilities of the ligand towards copper and nickel ions indifferent solvent media were investigated The ligand showed a strong binding affinity towards the metals ions with an extractiveefficiency of about 99

1 Introduction

Adduct formation (interaction of metal complexes with vari-ous ligating Lewis bases) allows the increase in coordinationnumber of metal ions in a complex while maintaining thesame oxidation state [1ndash3] Often the physical properties ofthe resulting adducts are significantly different from theirparent metal complexes and this influences their biologicalactivities [4ndash6] The ability or tendencies of metal complexesto form adducts differ and are closely related to the geometryof the coordinated ligand the ability of the Lewis base toaccept 120587-electrons and also the ionic size of the centralmetal ion [5] The drift of electron density towards the sulfur

atoms of dithiocarbamate bases due to the mesomeric effectof the ndashNR

2group influences the adduct formation of

dithiocarbamate complexes [1 3 7] When compared toother dithiolates such as the xanthate the ndashNR

2group

provides larger electrons towards the sulfur atoms resultingin the donation of electrons from the sulfur atoms to thenonbondingmolecular orbital of themetal [8]This decreasesits availability for axial interaction with Lewis bases [9]Subsequently the conventional route of additional reactionwhich leads to adduct formation is not always favored Theproperties of the R-group in the ndashNR

2moiety affects the

stability and other physicochemical properties of a metalcomplex Depending on the inductive effect (positive or

Hindawi Publishing CorporationBioinorganic Chemistry and ApplicationsVolume 2015 Article ID 913424 10 pageshttpdxdoiorg1011552015913424

2 Bioinorganic Chemistry and Applications

negative) of the group(s) on the nitrogen atom the flowof electrons towards the ligating CS

2group could either be

reduced or enhanced [10 11]Anumber of dithiocarbamate adducts have been reported

in literature [4 12ndash18] with various geometries such assquare planar [19] octahedral [20 21] and trigonal prismatic[22] Interestingly their pyridine [1 12 13] 221015840-bipyridine[13 15] triphenylphosphine [10] and 110-phenanthroline[1 15] adducts have been reported to possess antifungalproperties Some show activities against broad spectrum andare more active compared to their parent metal complexesand uncomplexed ligand [10]

Another important area where the property of dithio-carbamates has been employed in the environment is inthe separation of metal ions via solvent extraction due tothe strong chelating ability toward inorganic species Solventextraction involving chelation has been reported as one ofthe most widely used techniques in the preconcentration andseparation of metal ions from aqueous samples for analyticalpurposes due to its ease speed and wide scope [23 24]The technique has become more useful in recent years dueto the development of selective chelating agents for tracemetal determination [25ndash27] In solvent extraction a properchoice of extracting agents can achieve group separationor selective separation of trace elements with high effi-ciencies [25] For example sodium diethyldithiocarbamatecan extract over 40 metal species from aqueous solutionsinto organic solvents [23] The ability of these compoundsto form complexes is responsible for their extensive useas analytical reagents of environmental importance [26]The high tendencies of forming chelates with metal ionsat very low concentrations (120583gmL) make them versatilein the removal in preconcentration and also as extractiveagents in the determination of toxic heavy metal ions attrace and ultratrace levels [25] The dialkyldithiocarbamateshave been reported to have poor extractive ability in anacidic environment (low pH) and are highly unstable [2426] The half-life of 03 seconds of diethyldithiocarbamateat pH 2 describes the extreme instability of dialkyldithio-carbamate and this hinders measurement in acidic envi-ronments Monoalkyldithiocarbamates are more stable thandialkyldithiocarbamates in acidic solutions [26] Hence thereis need to develop dithiocarbamate bases that will functionas good preconcentration and extractive agents in differentenvironment (acidic and basic) media

Our earlierworkwas concernedwith the evaluation of theantibacterial properties of some transition metal complexesof N-methyl-N-phenyl dithiocarbamate which were foundto be promising as antibacterial agents [28] Considering thewide spread interest in dithiocarbamate compounds [29ndash31]and the interesting properties which occurs due to the changein the coordination number by the addition of Lewis bases toalready existing square planertetrahedral metal complexesit was considered of interest to study the antimicrobialproperties of some new pyridine adducts of transition metaldithiocarbamate complexes However our study showed thatwhile these adducts (unlike their precursor complexes in thereported study [28]) displayed no antibacterial propertiestheir antifungal activities are very good Herein we report

the synthesis characterization and antifungal activities ofthe pyridine adducts ofN-methyl-N-phenyl dithiocarbamatecomplexes of Mn(II) Co(II) Ni(II) and Cu(II) Further-more we report for the first time the extractability of Ni(II)and Cu(II) ions by N-methyl-N-phenyl dithiocarbamatefrom aqueous phase into the organic phaseThe nature of theextracted compoundwas also investigated using Jobrsquosmethodof continuous variation

2 Experimental

21 Physical Measurement All the chemical reagents usedwere of analytical grade and were used as received with-out further purification N-methyl aniline carbon disul-fide and sodium hydroxide were obtained from SigmaAldrich Pyridine nickel(II) chloride hexahydrate cobalt(II)chloride dihydrate copper(II) nitrate trihydrate anhydrouscopper(II) sulphate manganese(II) nitrate hexahydratenickel(II) nitrate hexahydrate pH tablets 1ndash10 ammoniadistilled water hydrochloric acid ammonia and chloro-form were obtained from Merck Co Infrared spectra wererecorded on a Bruker alpha-P FT-IR spectrometer in the500ndash4000 cmminus1 range Microanalyses were carried out witha Fisons elemental analyzer The thermal behaviour of thecompoundswas studied using an SDTQ600 thermogravime-try analyser Magnetic susceptibilities measurements werecarried out on a Johnson Matthey magnetic susceptibil-ity balance and diamagnetic corrections were calculatedusing Pascalrsquos constant Conductivity measurements wereconducted using a MC-1 Mark V conductivity meter witha cell constant of 10 UV-Vis spectra obtained on a PerkinElmer Lambda 40 UV-Vis spectrometer as solid reflectanceAtomic absorption spectrometer (Hitachi-18050) was used inpresent work

22 Synthesis of Compounds The reaction was carried out intwo stages which involved the reaction of the pyridine withthe hydrated metal salts followed by a displacement reactionwith the dithiocarbamate ligand

221 Synthesis of Sodium N-Methyl-N-phenyl Dithiocarba-mate [NaL] Sodium N-methyl-N-phenyl dithiocarbamatewas prepared according to the published procedure [28]A solution of sodium hydroxide (8 g 02mol) in 10mL ofdistilled water was prepared in a two-necked flask with athermometer To this solution 2180mL of N-methyl aniline(density 0985) was added and the mixture was stirred forapproximately 2 h at a low temperature range of 2ndash4∘C Theyellowish-white solid product which separated out was fil-tered washed with small portions of ether and recrystallizedin acetone

222 Synthesis of MCl2sdotpy2 Complexes The synthesis wascarried out according to the reported procedure [29] 15mLmethanol solution of pyridine was added to a 25mL solutionof the respective hydrated metal(II) chlorides in methanolin 1 2 molar ratios The mixture was refluxed for 1 hand the solution was left to evaporate off the solvent

Bioinorganic Chemistry and Applications 3

The precipitates obtained were collected washed severaltimes with methanol-water mixture to remove unreactedstarting materials and dried in vacuo [30]

223 Synthesis of the [ML2(py)2] To a 20mL solution ofMCl2sdotpy2[where M = Mn(II) Co(II) Ni(II) and Cu(II)]

in methanol (1mmol) was added a 20mL methanolic solu-tion of sodium N-methyl-N-phenyl dithiocarbamate (NaL)(2mmol) [31] with continuous stirring for about 60minat room temperature The precipitate formed was filteredwashed with methanol and water and dried in vacuo Thesynthesis procedure is presented in Scheme 2

[MnL2(py)2] yield (57) Selected IR 120592 (cmminus1) 1432 (C=N)1263 (C

2ndashN) and 920 (C=S) Electronic spectra (120582max

in nm) 340 nm 556 nm and 650 nm Anal Calc forC26H26N4S4Mn (57771) C 5405 H 454 N 970 S 2220

Found C 5428 H 480 N 1012 and S 2242

[CoL2(py)2] yield (64) Selected IR 120592 (cmminus1) 1438 (C=N)1262 (C

2ndashN) and 912 (C=S) Electronic spectra (120582max in

nm) 352 nm 366 nm 670 nm and 762 nm Anal Calc forC26H26N4S4Co (58170) C 5368 H 450 N 963 S 2205

Found C 5372 H 485 N 954 and S 2180

[NiL2(py)2] yield (52) Selected IR 120592 (cmminus1) 1440 (C=N)1260 (C


in nm) 341 nm 650 nm and 686 nm Anal Calc forC26H26N4S4Ni (58146) C 5371 H 451 N 964 S 2206

Found C 5402 H 398 N 932 and S 2191

[CuL2(py)2] yield (70) Selected IR 120592 (cmminus1) 1444 (C=N)1260 (C


in nm) 355 nm 539 nm and 545 nm Anal Calc forC26H26N4S4Cu (58632) C 5326 H 447 N 956 S 2188

Found C 5287 H 442 N 1008 and S 2214

23 Extraction Procedure Aqueous solutions containing 15times10minus3M metal salt in appropriate buffer of pH 1ndash10 wereequilibrated with equal volumes of the chloroform andmethanol solutions of the ligand 4 times 10minus4M by shaking in amechanical shaker at 25∘CThemethanolwas used to dissolvethe ligand due to its insolubility in chloroform The aqueousand organic phases were well agitated increasing the contactand homogenizing the concentrations of the different speciesin order that the complexation reaction would not be limitedby diffusion After agitation the solutions were allowed tostand for 15minThe solution was transferred to a separatingfunnel where the aqueous layer was allowed to separate fromthe organic layer and transferred into a volumetric flaskThe extraction was repeated with chloroform (5mL) Theconcentration of copper(II) and nickel(II) ions in the aqueousphase was determined by AAS and that of the organic phasefrom the difference was determined by considering the massbalance [25 26]

231 Procedure for Continuous VariationMethod 0 1 2 3 45 and 6mL 4 times 10minus4M of nickel and copper salt solutions

were pipetted respectively and transferred into different50mL volumetric flasks (7 numbers) An aliquot of 6 5 4 32 1 and 0mL 4times 10minus4Mof the ligandwas added respectivelyin such a way that the mole fraction of solution remainedconstant The solution was buffered to pH 10 Wavelengthof maximum absorbance was noted against a blank whichappeared at 622 nm for copper solution and 640 nm for nickelsolution All the measurements were made at 25∘C

3 Results and Discussion

31 Synthesis The reaction of pyridine with the respectivemetal salts in methanol solution afforded the pyridine com-plexes which were used as the precursor compounds forthe formation of the pyridyl adducts of the dithiocarbamateAttempts to prepare pyridine adducts via the conventionalmethod which usually involves the introduction of Lewisbase into the preformed dithiocarbamate complex werenot successful All the compounds were stable at roomtemperature

32 FTIR Spectroscopy The IR spectra of all the compoundsshow (=CndashH) stretching vibration due to the aromaticring around 3040 cmminus1 [30] while the (ndashCndashH) stretchingvibration due to the CH

3group appeared around 2864 cmminus1

A strong band exhibited between 1430 and 1444 cmminus1 in thespectra of all the compounds is assigned to the thioureidebond These peaks are shifted to lower regions compared tothe compounds without the pyridine molecule suggestingthe addition of the Lewis base to the metal ion [2 3 6]The reduction in stretching frequency of thioureide in thepyridine adducts arises because of the relatively decreasedelectron flow of the nitrogen lone pair of electrons towardsthe central metal ion The additional pyridine moleculesresult in an increase in the electron density [2 7 8] Thev(CS2) vibration appeared between 910 and 920 cmminus1 as a

single band indicating a symmetrical bonding of the twosulfur atoms to the metal ion [32] The bands due to thepyridine molecules appeared in the range of 1601ndash1608 cmminus1in all the compounds Other peaks were masked by thedithiocarbamate ligands

33 Thermal Studies The thermal property of the com-pounds was studied by TGA in the temperature range of25 to 600∘C under nitrogen atmosphere and presented inFigure 1 Thermogravimetry data reflect the thermal stabilityof compoundsThe compounds showed very similar thermalbehaviourThedecomposition occurred in two stepsThefirstdegradation step is in the range of 65ndash95∘C and approxi-mately 27 of weight loss was observed which correspondsto two pyridine groups in agreement with Siddiqi et alreport [33] The second stage of decomposition is sharpin the range of 275 to 350∘C and involved the decompo-sition of the remaining organic moiety which constitutesapproximately 43 of the remaining mass of the complexThe residue left behind corresponds to the respective metalsulfide Finally the thermogram maintained a straight linewhich did not change even though heating proceeded up


10

20

30

40

50

60

70

80

90

100

110

Wei

ght (

)

120 220 320 420 52020Temperature (∘C)

[CuL2(py)2][MnL2(py)2]

[CoL2(py)2][NiL2(py)2]

Figure 1 TGA graphs of the compounds under nitrogen flow

to 600∘C indicating that there is no further decompositionHence respective metal sulfide is the end product of allthe complexes The thermal decomposition behaviour of thecomplexes appeared to be related to the size of the centralmetal ion After the release of the pyridine group the stabilityof the dithiocarbamate followed the order Ni gt Mn gt Co gtCu This observation is in agreement with the earlier report[28]

34 Electronic Spectra and Magnetic Moment Electronicspectra of all the complexes were recorded as solid reflectanceaccording to literature procedure [28] Absorption bands arethe result of electronic transitions within the ligands (119899 rarr120587lowast 120587 rarr 120587lowast) metal d-d transitions and charge transfer

transitions (metal to ligands and ligand to metal chargetransitions) [34 35] The bands around 340ndash366 nm in themetal adducts were due to the 119899 rarr 120587 transition from theC=N group of the pyridine molecule and dithiocarbamatemoiety

The electronic spectrum of the cobalt adducts showedabsorption bands around 366 nm 352 nm 670 nm and762 nm The bands around 352 and 366 nm are due to119899 rarr 120587

lowast transitions of the C=N group in the pyridineand the dithiocarbamate moiety [28 36] The d-d bandsat 670 nm and 762 nm are due to 4T

1g rarr 4A

2g and

4T1g rarr 4T

1g(p) transitions respectively for an octahedral

d7 geometry with 4F ground term [37 38] The assignmentof a low spin octahedral geometry to the cobalt adduct wascorroborated with a magnetic moment value of 182 BM Inhigh spin octahedral cobalt complexes themagneticmomentlies between 47 and 52 BM while low spin octahedral cobaltcomplexes show magnetic moment from 170 to 185 BM [3439]

The nickel adduct showed bands at 341 nm 650 nm and686 nm due to 119899 rarr 120587lowast transition in the UV region and

visible bands for 3A2g rarr 3T

1g(F) and 3A

2g rarr 3T

1g(P)

transitions consistent with an octahedral d8 system in 3Fground term [34] The 3A

2g rarr 3T

2g transition often tails

into the infrared region and thus it is not observed inthe visible region [40 41] The magnetic moment value of278 BM corroborates an octahedral geometry a magneticmoment of 290ndash330 BM is expected for an octahedral d8system The lower value may be due to antiferromagnetismA tetrahedral d8 system has a magnetic moment of 320ndash410 BM while a square planar nickel(II) complex will havea zero moment [40]

Octahedral d9 copper complexes are expected to have abroad spectrum due to 2Eg rarr 2T

1g with a 2D ground term

However due to Jahn-Teller effect caused by asymmetricalfilling of the eg set of orbitals a splitting of 2Eg and 2T

2g into

2B1g 2A2g and 2B

2g 2Eg respectively is usually observed

[42] Hence the transitions may lie within one envelope ormay resolve into two or three absorption band componentsThe ligand bands for the copper adduct were observed at355 nm and assigned to 119899 rarr 120587lowast transition The d-dtransition was observed at 539 nm and 545 nm due to Jahn-Teller effectThemagneticmoment for amononuclear coppercomplex irrespective of geometry is 19ndash22 BM [38] Thecopper adduct had a magnetic moment of 202 BM whichcollaborates its mononuclear nature

The Mn(II) adduct showed three weak bands at 340 nm556 nm and 650 nm one ligand band and two forbiddentransition bands typical of 6-coordinate octahedral geometryand was assigned to 119899 rarr 120587 and the forbidden transitions of6A1g rarr 4T

1g and 6A

1g rarr 4T

2g (G)The effective magnetic

moments of Mn(II) complexes are expected to be close to thespin-only value of 590 BM Since the ground term is 6A

1g

there is no orbital contribution Consequently a moment of571 BM observed for this complex indicates that it is highspin and complementary of octahedral geometry [36 43]

35 Molar Conductivity Measurement The results of theelemental analysis are in good agreement with the calcu-lated values The metal contents of the complexes weredetermined according to literature methods [28] Theelectrolytic nature of the complexes was measured inDMSO at 10minus3M concentration The molar conductiv-ity values were 1916Ωminus1cm2molminus1 1306Ωminus1cm2molminus1244Ωminus1cm2molminus1 and 1084Ωminus1cm2molminus1 for NiL

2Py2

CuL2Py2 CoL2Py2 and MnL

2Py2 The results show that the

complexes were nonelectrolyte in nature [44 45]

36 Antifungal Screening

Disc Diffusion Method A disc application technique wasemployed in vitro to evaluate the antifungal activities ofthe pyridine adducts [46] The fungi used for the screeningwere Candida albicans a diploid fungus and a causal agentof opportunistic oral and genital infections in humansAspergillus flavus amold type fungal strainwhichmay invadearteries of the lung or brain to cause infections and alsoproduce a toxin andAspergillus nigerwhich is one of themost


Table 1 Antifungal activities of the pyridine adducts of119873-methyl-119873-phenyl dithiocarbamate

Compounds Candida albicans Aspergillus niger Aspergillus flavusLigand (NaL) 15 plusmn 07 8 plusmn 14 10 plusmn 07Co(L2)py2

21 plusmn 0 19 plusmn 04 19 plusmn 02Mn(L

2)py2

17 plusmn 02 15 plusmn 07 11 plusmn 04Cu(L2)py2

12 plusmn 07 13 plusmn 0 16 plusmn 02Ni(L2)py2

11 plusmn 0 18 plusmn 02 15 plusmn 15Fluconazole 23 plusmn 0 21 plusmn 02 20 plusmn 0DMSO mdash mdash mdash

0 10 20 30

Ligand (NaL)

Fluconazole

DMSO

Antifungal activity

Aspergillus flavusAspergillus nigerCandida albicans

Inhibitory zones (mm)

Com

poun

ds

Ni(L2)py2

Co(L2)py2

Mn(L2)py2

Cu(L2)py2

Figure 2 A histogram representative of antifungal activities of thepyridine adducts

common causes for otomycosis [10]Mature conidia of fungalisolates were harvested from potato dextrose agar (PDA)plates and suspended in ringer solution Conidial suspension(1mL) representing each fungal isolate was then spread ona 90mm Petri dish containing PDA (20mL) with the excessof the conidial suspension decanted and allowed to dry Thecompounds 100120583gMl were dissolved in dimethyl sulfoxide(DMSO) Sterile 6mm diameter test discs were impregnatedwith 15 120583L of the solution of each test compound to contain100 120583gdisc in triplicate Fluconazole (100120583gdisc) was usedas a reference drug for fungal inhibition while DMSO wasused as a negative control Plates were incubated at roomtemperature for 24 h The radius of the inhibition zone offungal growth was measured after 1 day and expressed as theinhibition zone in mm The results are presented in Table 1and Figure 2 is the histogram representation of the activities

The screened compounds displayed good in vitro antifun-gal inhibitory properties at the experimental concentrationof 100 120583gmL The complexes showed improved antifungalinhibition compared to the uncomplexed ligandThis may beattributed to the increased toxicity of the complexes due to thepresence of the pyridine molecules and the metal ions Thecobalt adduct showed the best inhibitory properties among

the test compounds and was 91 as active as fluconazoleagainst Candida albicans The screened compounds were allactive against Aspergillus spp The cobalt complex was 90and 95 as active as fluconazole against A niger and Aflavus respectively thereby proving its usefulness as leadcompounds in broad spectrum research for fungal organismsAntibacterial study of the compounds involving Gram posi-tive and Gram negative bacteria was carried out in vitro Thecomplexes showed no toxicity towards the various bacteriausedThe absence of antibacterial activities observed in thesecompounds could be ascribed to the poor permeability ofthe compounds through the bacterial cell wall or lack ofavailable coordination sites due to the octahedral geometryof the adducts

Dithiocarbamates have been reported to react withHS containing enzymes and coenzymes of fungal cells toform isothiocyanates which is fungitoxic in nature [47ndash49]Enzyme inhibition could also be possible by complex for-mation of dithiocarbamate ligand with metal atoms of metalcontaining enzymes [50] Some dithiocarbamate compoundslike NN-dimethyldithiocarbamates penetrate the cell mem-brane of the fungi before it is reduced to isothiiocyanates toexact its antifungal effect [51] However the mechanism ofthe action of metal complexes of dithiocarbamate is not fullyunderstood According to some authors metal complexesreact with copper containing proteins or enzymes and blockthem from being functional This reaction depends on thedegree of stability of the newly formed compound comparedto the former The copper ion in the protein or enzyme willreplace the metal ion of the complex forming a biomolecularcomplex thereby disrupting the normal functioning of theprotein or enzyme in the fungi The more stable the enzyme-complex the higher its fungicidal effect [52]

Metal complexes of 2 1 metal to ligand ratio are oftenconsidered nontoxic to fungi due to their very low watersolubility which makes it difficult to penetrate the cellmembrane Inconsistency in the assertion according to someauthors is due to the conversion of such complexes to a1 1 ratio within the fungi cells [52] That might possibly bethe reason why the metal complexes of N-methyl-N-phenyldithiocarbamate reported in our previous work [28] showedno antifungal activityHowever themode of action of adductsof dithiocarbamate complexes is an unsettled question Inorder to understand the functions responsible for antifungalactivities of pyridine adducts of dithiocarbamate complexesmore studies are needed to be carried out with a series ofanalogous ligands and their complexes against a series ofphytopathogenic fungi

37 Solvent Extraction Studies On addition of the ligand tothe aqueous phase it reacts with copper and nickel to formcolored metal complexes which transfer from the aqueousphase to the organic phase Maximum color developmentoccurred within 3min (Scheme 2) The copper solutionturned reddish-brown and the nickel solution turned green-ish on the addition of the ligand The ligandrsquos metal ionextraction was studied with the simultaneous determinationof Ni2+ and Cu2+ in aqueous phase at different pH levels


Table 2 Extraction efficiency of nickel ion at different pH levels

pHAmount of metal found in

the aqueous phase120583gmL

Amount of metal in theorganic phase120583gmL

Distribution ratioPercentageextraction

12 295 8586 0967 96725 342 8539 0962 96232 304 8577 0966 96642 196 8685 0978 97853 152 8729 0983 98365 114 8767 0987 98773 102 8779 0989 98982 121 8760 0986 98693 118 8763 0987 987102 086 8795 0990 990

Table 3 Extraction efficiency of copper ion at different pH levels



Amount of metal found inthe organic phase120583gmL


12 408 9140 0957 957025 429 9119 0955 955032 463 9085 0951 951042 399 9149 0958 958053 327 9221 0966 966065 305 9243 0968 968073 268 9280 0972 972082 271 9277 0972 972093 242 9306 0975 9750102 132 9416 0986 9860

The obtained results are expressed in terms of the extractionratio 119877() and the partition coefficient D (Tables 2 and 3) asfollows

119877 =[119872119894] minus [119872

119891]

[119872119894]

times 100

119863 =

[119872119894] minus [119872

119891]

[119872119894]

(1)

where [119872119894] and [119872

119891] are the initial and final concentrations

in the aqueous phaseThe degree of separation was determined in terms of

separation factor 119878119891 defined as the ratio of distribution ratio

for nickel ion to the distribution ratio for copper ion

119878119891=

119863Ni119863Cu (2)

371 Effect of pH on Extraction The extractability and selec-tivity of metal ions were evaluated as a function of pH ThepH of the aqueous solution before extraction was varied from12 to 102 by using solutions of HNO

3(01M) and NaOH

(01M) The percentage extraction and distribution ratio aredescribed in Tables 2 and 3 and the graphical presentation isgiven in Figure 3

The highest extractability and selectivity for Ni+2 andCu+2 were achieved at pH 10The separation factor of Ni2+ toCu2+ at aqueous solution of pH 10 is 1 making N-methyl-N-phenyl dithiocarbamate anion a poor reagent in the selectiveseparation of nickel and copper ions in solution

The solvent extraction process may be represented by thefollowing

M2+(aq) + 119899NaL(org) larrrarr ML119899

(org) + 119899Na+

(aq) (3)

where NaL = the extractive reagent 119899 = number of moles M= Cu and Ni is ions The subscript (aq) and (org) denote theaqueous and organic phases respectively

The extraction mechanism corresponds to a cationexchange in which a complex of stoichiometric formula(CuL119899and NiL

119899) is formed in the organic phase liberating

at the same time 119899 moles of Na+1 ions in the aqueous phase[26] as presented in Scheme 1

The results presented in Tables 2 and 3 showed that theligand had the highest percentage extraction at a pH of 10with 990Ni and 986Cu ions extracted from the aqueous


S SS

M+

n

Organic phase

NaN

NNSS

MSminus

M = Ni and Cu ions

MLn

Organic phaseAqueous phase Aqueous phase

nNaL

CH3

CH3

CH3

+ [Na+]

n

Scheme 1 Schematic representation of the extraction process

2

H3C

CH3

H3C

N CS

S+

NN

N

SNC

SSN C

SM

minus2NaClCl Cl

NaM

N

Scheme 2 Synthesis procedure

945

95

955

96

965

97

975

98

985

99

995

Extr

actio

n (

)

2 4 6 8 10 120pH

Extraction for Cu ()Extraction for Ni ()

Figure 3 Graph of effect of pH on the extraction of copper ion ornickel ion extraction by N-methyl-N-phenyl dithiocarbamate

phase into the organic phase Interestingly the ligand alsorecorded a very good percentage extraction values at an acidicpH (1ndash5)Thismakes the ligand suitable for solvent extractionstudy in both acidic and basic media

372 Nature of the Specie in the Organic Phase at pH 10The nature of the extracted species in the organic phaseat the pH with the best extractive potentials by the ligand(pH 10) was investigated using Jobrsquos method of continu-ous variation The results are presented in Table 4 andFigure 4 According to the results the metal to ligand ratio

Table 4 Experimental data for nickel(II) and copper(II) extractionby Jobrsquos continuous variation method

Number Metal ligandmL

Absorbance fornickel(II)complex


1 0 6 0124 01482 1 5 0168 03223 2 4 0243 03774 3 3 0201 03515 4 2 0104 02316 5 1 0084 01917 6 0 0051 0172

of 2 4 gave the maximum absorbance for both nickel andcopper This implies that the species in organic phases atpH 10 are four coordinate complexes of bis(N-methyl-N-phenyl dithiocarbamate) copper(II) and bis(N-methyl-N-phenyl dithiocarbamate) nickel(II) respectively which is inagreement with the reported stoichiometry [28]

4 Conclusions

In conclusion a series of pyridine adducts of N-methyl-N-phenyl dithiocarbamate were synthesized and their structurehas been established on the basis of spectral studies mag-netic moment measurements and elemental analysis Thecompounds and the dithiocarbamate ligand were evaluatedfor antifungal properties against three important pathogensnamely Aspergillus flavus Aspergillus niger and Candidaalbicans The adducts displayed better antifungal inhibitory


Nickel(II) complexCopper(II) complex

0

005

01

015

02

025

03

035

04

Abso

rban

ce (n

m)

4 022 04 3 03 5 010 06 6 001 05Metal ligand ratio

Figure 4 Jobrsquos curves of equimolar solutions at 622 nm copper ionand 640 nm nickel ion extraction

activity than the dithiocarbamate ligand Cobalt complexshowed the highest activity among the test compoundsMetalions extraction studies showed that the ligand has strongextractive ability towards Cu and Ni ions in both acidicand basic medium with its best condition at pH 10 Theselective separation of the ligand for Cu and Ni from aqueoussolution was small indicating that the ligand is not an idealcompound for separating these two metals in a mixture ofboth The adducts have potentials as lead compounds inbroad spectrum research for antifungal agents and the ligandis a good reagent for preconcentration and extraction ofmetalions in different media

Conflict of Interests

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

Acknowledgments

ACE acknowledges the assistance of the technologists inDepartment of Chemistry Federal University Ndufu-AlikeIkwo Mrs Rachel Otu Chioma and Mr Samson Bello fortheir contribution during the solvent extraction phase of thiswork Dr Aderoju Osowole of the Department of ChemistryUniversity of Ibadan and Drs Obinna Oje and Nnaji NJ of Department of Biochemistry and Chemistry FederalUniversity Ndufu-Alike Ikwo are acknowledged for theirinputs during the study

References

[1] B K Shashi K Geetanjli and Priyanka ldquoSynthesis and char-acterization of pyridine adducts of some transition metal 4-methylpiperazine-1-carbodithioic acid complexesrdquo HimachalPradesh University Journal pp 1ndash8 2011

[2] D C Onwudiwe C A Strydom and E C Hosten ldquoEffectof methyl substituent in pyridine on the spectral and thermal

properties of pyridyl adducts of Zn(II) and Cd(II) dithiocarba-materdquo Inorganica Chimica Acta vol 401 pp 1ndash10 2013

[3] B A Prakasam K Ramalingam G Bocelli and A CantonildquoSpectral BVS and thermal studies on bisdithiocarbamatesof divalent Zn Cd and their adducts single crystal x-raystructure redetermination of (Diiodo) (Tetraethylthiuramdisul-fide)mercury(II) [Hg(tetds)I

2]rdquo Phosphorus Sulfur and Silicon

and the Related Elements vol 184 no 8 pp 2020ndash2033 2009[4] A L Doadrio J Sotelo and A Fernandez-Ruano ldquoSynthesis

and characterization of oxovanadium (IV) dithiocarbamateswith pyridinerdquo Quimica Nova vol 25 no 4 pp 525ndash528 2002

[5] D Coucouvanis and J P Fackler Jr ldquoSquare-planar sulfur com-plexes VI Reactions of bases with xanthates dithiocarbamatesand dithiolates of nickel(II)rdquo Inorganic Chemistry vol 6 no 11pp 2047ndash2053 1967

[6] G Hogarth ldquoTransition metal dithiocarbamates 1978ndash2003rdquoProgress in Inorganic Chemistry vol 53 pp 71ndash561 2005

[7] E R T Tiekink and I Haiduc ldquoStereochemical aspects of metalxanthate complexes molecular structures and supramolecularself-assemblyrdquo Progress in Inorganic Chemistry vol 54 pp 127ndash319 2005

[8] R G Xiong J L Zuo and X Z You ldquoA novel dimeric zinccomplex bis120583-[(dimercaptomethylene)propanedinitrilato-SS1015840]tetrakis(4-methylpyridine)dizinc(II)-chloroformrdquo Inor-ganic Chemistry vol 36 no 11 pp 2472ndash2474 1997

[9] B Singh R N Singh and R C Aggarwal ldquoMagnetic and spec-tral studies on N-(thiophene-2-carboxamido)salicylaldiminecomplexes of some bivalent 3d metal ionsrdquo Polyhedron vol 4no 3 pp 401ndash407 1985

[10] S M Mamba Synthesis characterization and application ofdithiocarbamate transition metal complexes [PhD thesis] Uni-versity of Johannesburg Johannesburg South Africa 2011

[11] G G Mohamed N A Ibrahim and H A E Attia ldquoSynthesisand anti-fungicidal activity of some transition metal complexeswith benzimidazole dithiocarbamate ligandrdquo SpectrochimicaActamdashPart A Molecular and Biomolecular Spectroscopy vol 72no 3 pp 610ndash615 2009

[12] M Sharma and R Sachar ldquoSynthesis and characterization of theadducts of bis (NN-diethyldithiocarbamato) oxovanadium(IV)with substituted pyridinesrdquo Oriental Journal of Chemistry vol25 no 1 pp 215ndash218 2009

[13] A Manohar K Ramalingam G Bocelli and A CantonildquoSynthesis spectral and single crystal X-ray structural studieson bis(221015840-bipyridine)sulphidoM(II) (M = Cu or Zn) anddiaqua 221015840-bipyridine zinc(II)sulphate dehydraterdquo Journal ofthe Serbian Chemical Society vol 75 no 8 pp 1085ndash1092 2010

[14] A C Ekennia ldquoAntibacterial application of novel mixed-liganddithiocarbamate complexes of nickel (II)rdquo Journal of AppliedChemistry vol 5 no 2 pp 36ndash39 2013

[15] N Geetha and S Thirumaran ldquoCharacterization studies andcyclic voltammetry on nickel(II) amino acid dithiocarbamateswith triphenylphosphine in the coordination sphererdquo Journal ofthe Serbian Chemical Society vol 73 no 2 pp 169ndash177 2008

[16] S P Sovilj G Vuckovic M Leovac and D MinicldquoDinuclear copper(II) complexes of NN1015840N10158401015840N101584010158401015840-tetrakis(2-pyridilmethyl)-14811-tetrazacyclotetra decane and some NSor NO bidentante ligandsrdquo Polish Journal of Chemistry vol 74no 2 pp 945ndash954 2000

[17] M Sharma A Sharma and R Sachar ldquoPreparation andcharacterization of the adducts of Bis(NN-diethyldithiocar-bamato)oxovanadium(IV) and copper(II) with n-propylamine


and isopropylaminerdquo Chemical Science Transactions vol 2 no2 pp 367ndash374 2013

[18] M Sharma A Sharma and R Sachar ldquoSynthesis and char-acterization of the adducts of morpholinedithioccarbamatecomplexes of oxovanadium (IV) nickel(II) and copper(II) withpiperidine and morpholinerdquo E-Journal of Chemistry vol 9 no4 pp 1929ndash1940 2012

[19] D C Onwudiwe and P A Ajibade ldquoSynthesis character-ization and thermal studies of Zn(II) Cd(II) and Hg(II)complexes of N-Methyl-N-Phenyldithiocarbamate the singlecrystal structure of [(C

6H5)(CH3)NCS

2]4Hg2rdquo International

Journal of Molecular Sciences vol 12 no 3 pp 1964ndash1978 2011[20] A A Osowole G A Kolawole and O E Fagade ldquoSynthesis

physicochemical and biological properties of nickel(II) cop-per(II) and zinc(II) complexes of an unsymmetrical tetraden-tate Schiff base and their adductsrdquo Synthesis and Reactivity inInorganic Metal-Organic and Nano-Metal Chemistry vol 35no 10 pp 829ndash836 2005

[21] G A Kolawole and A A Osowole ldquoSynthesis and characteri-zation of some metal(II) complexes of isomeric unsymmetricalSchiff bases and their adductswith triphenylphosphinerdquo Journalof Coordination Chemistry vol 62 no 9 pp 1437ndash1448 2009

[22] T Guo C S Lai X J Tan C S Teo and E R TiekinkldquoBis(diethyldithiocarbamato)(47-dimethyl-110-phenanthro-line)cadmium(II) acetonitrile solvaterdquoActa CrystallographicamdashSection E Structure Reports Online vol 58 no 8 pp m439ndashm440 2002

[23] CMWai and S JWang ldquoIon exchange and solvent extractiona series of advancesrdquo Journal of Chromatography A vol 785 pp369ndash383 1997

[24] W A Zoubi F Kandil and M K Chebani ldquoSolvent extractionof chromium and copper using Schiff base derived from tereph-thaldialdehyde and 5-amino-2-methoxy-phenolrdquoArabian Jour-nal of Chemistry 2011

[25] B Dede F Karipcin andM Cengiz ldquoNovel homo- and hetero-nuclear copper(II) complexes of tetradentate Schiff basessynthesis characterization solvent-extraction and catalase-likeactivity studiesrdquo Journal of Hazardous Materials vol 163 no 2-3 pp 1148ndash1156 2009

[26] S Kanchi P Singh and K Bisetty ldquoDithiocarbamates ashazardous remediation agent a critical review on progress inenvironmental chemistry for inorganic species studies of 20thcenturyrdquo Arabian Journal of Chemistry vol 7 no 1 pp 11ndash252014

[27] M M Aniruddha H Sung-H A A Mansing and S KSanjay ldquoLiquidndashliquid anion exchange extraction studies ofsamarium(III) from salicylate media using high molecularweight aminerdquo Arabian Journal of Chemistry vol 8 no 4 pp456ndash464 2015

[28] A C Ekennia D C Onwudiwe and A A Osowole ldquoSpectralthermal stability and antibacterial studies of copper nickeland cobalt complexes ofN-methyl-N-phenyl dithiocarbamaterdquoJournal of Sulfur Chemistry vol 36 no 1 pp 96ndash104 2015

[29] K S Siddiqi S A A Nami Lutfullah and Y Chebude ldquoSyn-thesis characterization and thermal studies of bipyridine metalcomplexes containing different substituted dithiocarbamatesrdquoSynthesis and Reactivity in Inorganic Metal-Organic and Nano-Metal Chemistry vol 35 no 6 pp 445ndash451 2005

[30] J C Bailar H J Emeleus R Nyholm and A F Trotman-Dickenson Comprehensive Inorganic Chemistry vol 3 Perga-mon Press Oxford UK 1973

[31] D C Onwudiwe and P A Ajibade ldquoSynthesis and crystal struc-ture of Bis(N-alkyl-N-phenyl dithiocarbamato)mercury(II)rdquoJournal of Chemical Crystallography vol 41 no 7 pp 980ndash9852011

[32] F Bonati and R Ugo ldquoOrganotin(IV)NN-disubstituted dithio-carbamatesrdquo Journal of Organometallic Chemistry vol 10 no 2pp 257ndash268 1967

[33] K S Siddiqi S Khan S A A Nami and M M El-ajailyldquoPolynuclear transition metal complexes with thiocarbohy-drazide and dithiocarbamatesrdquo Spectrochimica ActamdashPart AMolecular and Biomolecular Spectroscopy vol 67 no 3-4 pp995ndash1002 2007

[34] M G Abd El-Wahed M S Refat and S M El-MegharbelldquoMetal complexes of antiuralethic drug synthesis spectro-scopic characterization and thermal study on allopurinol com-plexesrdquo Journal ofMolecular Structure vol 888 no 1ndash3 pp 416ndash429 2008

[35] T L Yang and W W Qin ldquoTransition metal manganese(II)nickel(II) copper(II) and zinc(II) complexes of a new Schiffbase ligand synthesis characterization and antitumor activitystudiesrdquo Polish Journal of Chemistry vol 80 no 10 pp 1657ndash1662 2006

[36] A B P Lever Inorganic Electronic Spectroscopy Elsevier 1973[37] A A Osowole G A Kolawole and O E Fagade ldquoSyn-

thesis and characterization of some metal(II) complexes ofisomeric unsymmetrical Schiff bases and their adducts withtriphenylphosphinerdquo Journal of CoordinationChemistry vol 62no 9 pp 1437ndash1448 2008

[38] N Raman S Ravichandran and C Thangaraja ldquoCopper(II)cobalt(II) nickel(II) and zinc(II) complexes of Schiff basederived from benzil-24-dinitrophenylhydrazone with anilinerdquoJournal of Chemical Sciences vol 116 no 4 pp 215ndash219 2004

[39] B N Figgis Introduction to Ligand Fields Interscience NewYork NY USA 1966

[40] M Soenmez A Levent and M Sekerci ldquoSynthesis charac-terization and thermal investigation of some metal complexescontaining polydentate ONOdonor heterocyclic Schiff baseligandrdquo Russian Journal of Coordination Chemistry vol 30 no9 pp 655ndash659 2004

[41] M Soenmez and M A Sekerci ldquoNew heterocyclic Schiff baseand its metal complexesrdquo Synthesis and Reactivity in InorganicMetal-Organic and Nano-Metal Chemistry vol 34 no 3 pp489ndash502 2004

[42] D Nicholls Comprehensive Inorganic Chemistry vol 3 Wiley1973

[43] A EarnshawThe Introduction to Magnetochemistry AcademicPress London UK 1980

[44] W J Geary ldquoThe use of conductivity measurements in organicsolvents for the characterisation of coordination compoundsrdquoCoordination Chemistry Reviews vol 7 no 1 pp 81ndash122 1971

[45] A A Osowole R Kempe R Schobert and K EffenbergerldquoSynthesis spectroscopic thermal and in vitro anticancerproperties of some M(II) complexes of 3-(-1-(46-dimethyl-2-pyrimidinylimino)methyl-2-naphtholrdquo Synthesis and Reactivityin Inorganic Metal-Organic and Nano-Metal Chemistry vol 41no 7 pp 825ndash833 2011

[46] M A R Ahamed R S Azarudeen and N M Kani ldquoAntimi-crobial applications of transition metal complexes of benzoth-iazole based terpolymer synthesis characterization and effecton bacterial and fungal strainsrdquo Bioinorganic Chemistry andApplications vol 2014 Article ID 764085 16 pages 2014


[47] R TWedding and J B Kendrick ldquoToxicity of N-methyl dithio-carbamate and methyl isothiocyanate to Rhizoctonia solanirdquoPhytopathology vol 49 pp 557ndash561 1959

[48] G J M Van Der Kerk ldquoThe present state of fungicide researchAchtste J arlijks Symposium over Phytopharmacierdquo MededeelLandbouwhogeschool Gent vol 21 pp 305ndash339 1956

[49] ldquoChemical structure and fungicidal activity of dithiocarba-matesrdquo in Plant Pathology Problems and Progress 1908ndash1958 GS Holton Ed University of Wisconsin Press Madison WisUSA 1959

[50] R G Owens ldquoStudies on the nature of fungicidal action IInhibition of sulfhydryl amino iron and copper-dependentenzymes in vitro by fungicides and related compoundsrdquo Con-tributions from Boyce Thompson Institute vol 17 pp 221ndash2421953

[51] L T Richardson and G D Thorn ldquoThe interaction of thiramand spores of Glomerella cingulata Spauld amp Schrenkrdquo Cana-dian Journal of Botany vol 39 no 3 pp 531ndash540 1961

[52] G Eckert ldquoThe use of disubstituted dithiocarbamates foranalytical seperationsrdquo Zeitschrift fur Analytische Chemie vol155 pp 23ndash34 1957

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


negative) of the group(s) on the nitrogen atom the flowof electrons towards the ligating CS

2group could either be

reduced or enhanced [10 11]Anumber of dithiocarbamate adducts have been reported

in literature [4 12ndash18] with various geometries such assquare planar [19] octahedral [20 21] and trigonal prismatic[22] Interestingly their pyridine [1 12 13] 221015840-bipyridine[13 15] triphenylphosphine [10] and 110-phenanthroline[1 15] adducts have been reported to possess antifungalproperties Some show activities against broad spectrum andare more active compared to their parent metal complexesand uncomplexed ligand [10]

Another important area where the property of dithio-carbamates has been employed in the environment is inthe separation of metal ions via solvent extraction due tothe strong chelating ability toward inorganic species Solventextraction involving chelation has been reported as one ofthe most widely used techniques in the preconcentration andseparation of metal ions from aqueous samples for analyticalpurposes due to its ease speed and wide scope [23 24]The technique has become more useful in recent years dueto the development of selective chelating agents for tracemetal determination [25ndash27] In solvent extraction a properchoice of extracting agents can achieve group separationor selective separation of trace elements with high effi-ciencies [25] For example sodium diethyldithiocarbamatecan extract over 40 metal species from aqueous solutionsinto organic solvents [23] The ability of these compoundsto form complexes is responsible for their extensive useas analytical reagents of environmental importance [26]The high tendencies of forming chelates with metal ionsat very low concentrations (120583gmL) make them versatilein the removal in preconcentration and also as extractiveagents in the determination of toxic heavy metal ions attrace and ultratrace levels [25] The dialkyldithiocarbamateshave been reported to have poor extractive ability in anacidic environment (low pH) and are highly unstable [2426] The half-life of 03 seconds of diethyldithiocarbamateat pH 2 describes the extreme instability of dialkyldithio-carbamate and this hinders measurement in acidic envi-ronments Monoalkyldithiocarbamates are more stable thandialkyldithiocarbamates in acidic solutions [26] Hence thereis need to develop dithiocarbamate bases that will functionas good preconcentration and extractive agents in differentenvironment (acidic and basic) media

Our earlierworkwas concernedwith the evaluation of theantibacterial properties of some transition metal complexesof N-methyl-N-phenyl dithiocarbamate which were foundto be promising as antibacterial agents [28] Considering thewide spread interest in dithiocarbamate compounds [29ndash31]and the interesting properties which occurs due to the changein the coordination number by the addition of Lewis bases toalready existing square planertetrahedral metal complexesit was considered of interest to study the antimicrobialproperties of some new pyridine adducts of transition metaldithiocarbamate complexes However our study showed thatwhile these adducts (unlike their precursor complexes in thereported study [28]) displayed no antibacterial propertiestheir antifungal activities are very good Herein we report

the synthesis characterization and antifungal activities ofthe pyridine adducts ofN-methyl-N-phenyl dithiocarbamatecomplexes of Mn(II) Co(II) Ni(II) and Cu(II) Further-more we report for the first time the extractability of Ni(II)and Cu(II) ions by N-methyl-N-phenyl dithiocarbamatefrom aqueous phase into the organic phaseThe nature of theextracted compoundwas also investigated using Jobrsquosmethodof continuous variation

2 Experimental

21 Physical Measurement All the chemical reagents usedwere of analytical grade and were used as received with-out further purification N-methyl aniline carbon disul-fide and sodium hydroxide were obtained from SigmaAldrich Pyridine nickel(II) chloride hexahydrate cobalt(II)chloride dihydrate copper(II) nitrate trihydrate anhydrouscopper(II) sulphate manganese(II) nitrate hexahydratenickel(II) nitrate hexahydrate pH tablets 1ndash10 ammoniadistilled water hydrochloric acid ammonia and chloro-form were obtained from Merck Co Infrared spectra wererecorded on a Bruker alpha-P FT-IR spectrometer in the500ndash4000 cmminus1 range Microanalyses were carried out witha Fisons elemental analyzer The thermal behaviour of thecompoundswas studied using an SDTQ600 thermogravime-try analyser Magnetic susceptibilities measurements werecarried out on a Johnson Matthey magnetic susceptibil-ity balance and diamagnetic corrections were calculatedusing Pascalrsquos constant Conductivity measurements wereconducted using a MC-1 Mark V conductivity meter witha cell constant of 10 UV-Vis spectra obtained on a PerkinElmer Lambda 40 UV-Vis spectrometer as solid reflectanceAtomic absorption spectrometer (Hitachi-18050) was used inpresent work

22 Synthesis of Compounds The reaction was carried out intwo stages which involved the reaction of the pyridine withthe hydrated metal salts followed by a displacement reactionwith the dithiocarbamate ligand

221 Synthesis of Sodium N-Methyl-N-phenyl Dithiocarba-mate [NaL] Sodium N-methyl-N-phenyl dithiocarbamatewas prepared according to the published procedure [28]A solution of sodium hydroxide (8 g 02mol) in 10mL ofdistilled water was prepared in a two-necked flask with athermometer To this solution 2180mL of N-methyl aniline(density 0985) was added and the mixture was stirred forapproximately 2 h at a low temperature range of 2ndash4∘C Theyellowish-white solid product which separated out was fil-tered washed with small portions of ether and recrystallizedin acetone

222 Synthesis of MCl2sdotpy2 Complexes The synthesis wascarried out according to the reported procedure [29] 15mLmethanol solution of pyridine was added to a 25mL solutionof the respective hydrated metal(II) chlorides in methanolin 1 2 molar ratios The mixture was refluxed for 1 hand the solution was left to evaporate off the solvent








Found C 5428 H 480 N 1012 and S 2242




Found C 5372 H 485 N 954 and S 2180




Found C 5402 H 398 N 932 and S 2191




Found C 5287 H 442 N 1008 and S 2214












10

20

30

40

50

60

70

80

90

100

110

Wei

ght (

)

120 220 320 420 52020Temperature (∘C)









1g rarr 4A

2g and

4T1g rarr 4T





1g(F) and 3A

2g rarr 3T

1g(P)


2g rarr 3T






2g into

2B1g 2A2g and 2B




1g and 6A

1g rarr 4T



1g



2Py2










2)py2




0 10 20 30

Ligand (NaL)

Fluconazole

DMSO

Antifungal activity



Com

poun

ds

Ni(L2)py2

Co(L2)py2

Mn(L2)py2

Cu(L2)py2














12 295 8586 0967 96725 342 8539 0962 96232 304 8577 0966 96642 196 8685 0978 97853 152 8729 0983 98365 114 8767 0987 98773 102 8779 0989 98982 121 8760 0986 98693 118 8763 0987 987102 086 8795 0990 990






12 408 9140 0957 957025 429 9119 0955 955032 463 9085 0951 951042 399 9149 0958 958053 327 9221 0966 966065 305 9243 0968 968073 268 9280 0972 972082 271 9277 0972 972093 242 9306 0975 9750102 132 9416 0986 9860


119877 =[119872119894] minus [119872

119891]

[119872119894]

times 100

119863 =

[119872119894] minus [119872

119891]

[119872119894]

(1)

where [119872119894] and [119872





119878119891=

119863Ni119863Cu (2)


3(01M) and NaOH





(org) + 119899Na+

(aq) (3)







S SS

M+

n

Organic phase

NaN

NNSS

MSminus

M = Ni and Cu ions

MLn


nNaL

CH3

CH3

CH3

+ [Na+]

n


2

H3C

CH3

H3C

N CS

S+

NN

N

SNC

SSN C

SM

minus2NaClCl Cl

NaM

N


945

95

955

96

965

97

975

98

985

99

995

Extr

actio

n (

)

2 4 6 8 10 120pH









1 0 6 0124 01482 1 5 0168 03223 2 4 0243 03774 3 3 0201 03515 4 2 0104 02316 5 1 0084 01917 6 0 0051 0172


4 Conclusions




0

005

01

015

02

025

03

035

04

Abso

rban

ce (n

m)






Acknowledgments


References

























6H5)(CH3)NCS














































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of








Found C 5428 H 480 N 1012 and S 2242




Found C 5372 H 485 N 954 and S 2180




Found C 5402 H 398 N 932 and S 2191




Found C 5287 H 442 N 1008 and S 2214












10

20

30

40

50

60

70

80

90

100

110

Wei

ght (

)

120 220 320 420 52020Temperature (∘C)









1g rarr 4A

2g and

4T1g rarr 4T





1g(F) and 3A

2g rarr 3T

1g(P)


2g rarr 3T






2g into

2B1g 2A2g and 2B




1g and 6A

1g rarr 4T



1g



2Py2










2)py2




0 10 20 30

Ligand (NaL)

Fluconazole

DMSO

Antifungal activity



Com

poun

ds

Ni(L2)py2

Co(L2)py2

Mn(L2)py2

Cu(L2)py2














12 295 8586 0967 96725 342 8539 0962 96232 304 8577 0966 96642 196 8685 0978 97853 152 8729 0983 98365 114 8767 0987 98773 102 8779 0989 98982 121 8760 0986 98693 118 8763 0987 987102 086 8795 0990 990






12 408 9140 0957 957025 429 9119 0955 955032 463 9085 0951 951042 399 9149 0958 958053 327 9221 0966 966065 305 9243 0968 968073 268 9280 0972 972082 271 9277 0972 972093 242 9306 0975 9750102 132 9416 0986 9860


119877 =[119872119894] minus [119872

119891]

[119872119894]

times 100

119863 =

[119872119894] minus [119872

119891]

[119872119894]

(1)

where [119872119894] and [119872





119878119891=

119863Ni119863Cu (2)


3(01M) and NaOH





(org) + 119899Na+

(aq) (3)







S SS

M+

n

Organic phase

NaN

NNSS

MSminus

M = Ni and Cu ions

MLn


nNaL

CH3

CH3

CH3

+ [Na+]

n


2

H3C

CH3

H3C

N CS

S+

NN

N

SNC

SSN C

SM

minus2NaClCl Cl

NaM

N


945

95

955

96

965

97

975

98

985

99

995

Extr

actio

n (

)

2 4 6 8 10 120pH









1 0 6 0124 01482 1 5 0168 03223 2 4 0243 03774 3 3 0201 03515 4 2 0104 02316 5 1 0084 01917 6 0 0051 0172


4 Conclusions




0

005

01

015

02

025

03

035

04

Abso

rban

ce (n

m)






Acknowledgments


References

























6H5)(CH3)NCS














































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


10

20

30

40

50

60

70

80

90

100

110

Wei

ght (

)

120 220 320 420 52020Temperature (∘C)









1g rarr 4A

2g and

4T1g rarr 4T





1g(F) and 3A

2g rarr 3T

1g(P)


2g rarr 3T






2g into

2B1g 2A2g and 2B




1g and 6A

1g rarr 4T



1g



2Py2










2)py2




0 10 20 30

Ligand (NaL)

Fluconazole

DMSO

Antifungal activity



Com

poun

ds

Ni(L2)py2

Co(L2)py2

Mn(L2)py2

Cu(L2)py2














12 295 8586 0967 96725 342 8539 0962 96232 304 8577 0966 96642 196 8685 0978 97853 152 8729 0983 98365 114 8767 0987 98773 102 8779 0989 98982 121 8760 0986 98693 118 8763 0987 987102 086 8795 0990 990






12 408 9140 0957 957025 429 9119 0955 955032 463 9085 0951 951042 399 9149 0958 958053 327 9221 0966 966065 305 9243 0968 968073 268 9280 0972 972082 271 9277 0972 972093 242 9306 0975 9750102 132 9416 0986 9860


119877 =[119872119894] minus [119872

119891]

[119872119894]

times 100

119863 =

[119872119894] minus [119872

119891]

[119872119894]

(1)

where [119872119894] and [119872





119878119891=

119863Ni119863Cu (2)


3(01M) and NaOH





(org) + 119899Na+

(aq) (3)







S SS

M+

n

Organic phase

NaN

NNSS

MSminus

M = Ni and Cu ions

MLn


nNaL

CH3

CH3

CH3

+ [Na+]

n


2

H3C

CH3

H3C

N CS

S+

NN

N

SNC

SSN C

SM

minus2NaClCl Cl

NaM

N


945

95

955

96

965

97

975

98

985

99

995

Extr

actio

n (

)

2 4 6 8 10 120pH









1 0 6 0124 01482 1 5 0168 03223 2 4 0243 03774 3 3 0201 03515 4 2 0104 02316 5 1 0084 01917 6 0 0051 0172


4 Conclusions




0

005

01

015

02

025

03

035

04

Abso

rban

ce (n

m)






Acknowledgments


References

























6H5)(CH3)NCS














































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





2)py2




0 10 20 30

Ligand (NaL)

Fluconazole

DMSO

Antifungal activity



Com

poun

ds

Ni(L2)py2

Co(L2)py2

Mn(L2)py2

Cu(L2)py2














12 295 8586 0967 96725 342 8539 0962 96232 304 8577 0966 96642 196 8685 0978 97853 152 8729 0983 98365 114 8767 0987 98773 102 8779 0989 98982 121 8760 0986 98693 118 8763 0987 987102 086 8795 0990 990






12 408 9140 0957 957025 429 9119 0955 955032 463 9085 0951 951042 399 9149 0958 958053 327 9221 0966 966065 305 9243 0968 968073 268 9280 0972 972082 271 9277 0972 972093 242 9306 0975 9750102 132 9416 0986 9860


119877 =[119872119894] minus [119872

119891]

[119872119894]

times 100

119863 =

[119872119894] minus [119872

119891]

[119872119894]

(1)

where [119872119894] and [119872





119878119891=

119863Ni119863Cu (2)


3(01M) and NaOH





(org) + 119899Na+

(aq) (3)







S SS

M+

n

Organic phase

NaN

NNSS

MSminus

M = Ni and Cu ions

MLn


nNaL

CH3

CH3

CH3

+ [Na+]

n


2

H3C

CH3

H3C

N CS

S+

NN

N

SNC

SSN C

SM

minus2NaClCl Cl

NaM

N


945

95

955

96

965

97

975

98

985

99

995

Extr

actio

n (

)

2 4 6 8 10 120pH









1 0 6 0124 01482 1 5 0168 03223 2 4 0243 03774 3 3 0201 03515 4 2 0104 02316 5 1 0084 01917 6 0 0051 0172


4 Conclusions




0

005

01

015

02

025

03

035

04

Abso

rban

ce (n

m)






Acknowledgments


References

























6H5)(CH3)NCS














































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of







12 295 8586 0967 96725 342 8539 0962 96232 304 8577 0966 96642 196 8685 0978 97853 152 8729 0983 98365 114 8767 0987 98773 102 8779 0989 98982 121 8760 0986 98693 118 8763 0987 987102 086 8795 0990 990






12 408 9140 0957 957025 429 9119 0955 955032 463 9085 0951 951042 399 9149 0958 958053 327 9221 0966 966065 305 9243 0968 968073 268 9280 0972 972082 271 9277 0972 972093 242 9306 0975 9750102 132 9416 0986 9860


119877 =[119872119894] minus [119872

119891]

[119872119894]

times 100

119863 =

[119872119894] minus [119872

119891]

[119872119894]

(1)

where [119872119894] and [119872





119878119891=

119863Ni119863Cu (2)


3(01M) and NaOH





(org) + 119899Na+

(aq) (3)







S SS

M+

n

Organic phase

NaN

NNSS

MSminus

M = Ni and Cu ions

MLn


nNaL

CH3

CH3

CH3

+ [Na+]

n


2

H3C

CH3

H3C

N CS

S+

NN

N

SNC

SSN C

SM

minus2NaClCl Cl

NaM

N


945

95

955

96

965

97

975

98

985

99

995

Extr

actio

n (

)

2 4 6 8 10 120pH









1 0 6 0124 01482 1 5 0168 03223 2 4 0243 03774 3 3 0201 03515 4 2 0104 02316 5 1 0084 01917 6 0 0051 0172


4 Conclusions




0

005

01

015

02

025

03

035

04

Abso

rban

ce (n

m)






Acknowledgments


References

























6H5)(CH3)NCS














































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


S SS

M+

n

Organic phase

NaN

NNSS

MSminus

M = Ni and Cu ions

MLn


nNaL

CH3

CH3

CH3

+ [Na+]

n


2

H3C

CH3

H3C

N CS

S+

NN

N

SNC

SSN C

SM

minus2NaClCl Cl

NaM

N


945

95

955

96

965

97

975

98

985

99

995

Extr

actio

n (

)

2 4 6 8 10 120pH









1 0 6 0124 01482 1 5 0168 03223 2 4 0243 03774 3 3 0201 03515 4 2 0104 02316 5 1 0084 01917 6 0 0051 0172


4 Conclusions




0

005

01

015

02

025

03

035

04

Abso

rban

ce (n

m)






Acknowledgments


References

























6H5)(CH3)NCS














































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



0

005

01

015

02

025

03

035

04

Abso

rban

ce (n

m)






Acknowledgments


References

























6H5)(CH3)NCS














































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





6H5)(CH3)NCS














































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

Mixed Ligand Complexes of N-Methyl-N-phenyl Dithiocarbamate ...

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