Research Article Synthesis, Crystal Structure, and...

Research ArticleSynthesis Crystal Structure and Antimicrobial Propertiesof [Diaquabis(hexamethylenetetramine)diisothiocyanato-120581N]nickel(II) Complex

Che Dieudonne Tabong1 Divine Mbom Yufanyi2 Awawou Gbambie Paboudam1

Katia Nchimi Nono1 Donatus Bekindaka Eni1 and Moise Ondoh Agwara1

1Department of Inorganic Chemistry Faculty of Science University of Yaounde I PO Box 812 Yaounde Cameroon2Department of Chemistry Faculty of Science The University of Bamenda PO Box 39 Bambili Bamenda Cameroon

Correspondence should be addressed to Moise Ondoh Agwara agwara29yahoocom

Received 23 April 2016 Revised 10 June 2016 Accepted 13 June 2016

Academic Editor Renal Backov

Copyright copy 2016 Che Dieudonne Tabong et alThis is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in anymedium provided the originalwork is properly cited

A nickel(II) complex with hexamethylenetetramine and thiocyanate ion as coligands has been synthesized and characterised byinfrared spectroscopy and ultraviolet-visible spectroscopic techniques The crystal structure of the complex was determined bysingle crystal X-ray diffraction and the ligands were found to coordinate terminally through N-atomsThe ligand and the complexwere screened for their activity against resistant strains of bacteria (Salmonella enteric Shigella flexneri Escherichia coli andStaphylococcus aureus) and fungi (Candida albicans Candida krusei Candida parapsilosis and Candida neoformans)

Dedicated to Professor Moise Ondoh Agwara on his 60th anniversary

1 Introduction

Recently the design and synthesis of novel coordinationcompounds inorganic-organic hybrid materials and coor-dination polymers with desired physicochemical propertiesare at the frontiers of inorganic chemistry research [1ndash6]To achieve this goal the rational design of particular struc-tures employing different synthetic approaches needs to bedeveloped followed by a study of the structure-propertyrelationships The rational choice of building blocks metalcentres and ligands is of crucial importance in the deliberateconstruction of coordination networks and the design ofmetal-based supramolecular architectures [7 8] Among theligands employed in the construction of these networkshexamethylenetetramine (HMTA) as a potential tetraden-tate ligand or hydrogen bond acceptor seems quite suit-able in self-assembly systems

Hexamethylenetetramine is a commercially availableorganic molecule which possesses three fused rings in the

chair conformation similar to the cage-like structure ofadamantine [9] It is cheap ecofriendly and readily availablefor reactions with many hydrated salts It forms molecu-lar complexes with varied coordination patterns rangingfrom monodentate [10] bridging [11 12] nonchelating tohydrogen-bonded frameworks [13ndash15] inducing the forma-tion of one- two- and three-dimensional framework struc-tures Biologically HMTA has several uses like a cosmeticbiocide in eye make-up preparation preservative in lotionsand creams or antiseptic agent for the treatment of urinarytract infections [16 17]

Among the inorganic anions serving as coligands thio-cyanate SCNminus (an ambidentate ligand) is very important dueto its great tendency to combine with a variety of metal ionsforming either thiocyanato (M-SCN) or isothiocyanato (M-NCS) complexes and also bridges metal ions In addition theantagonism between the ligands HMTA and SCNminus (neutraland ionic) as well as the solvent molecules influence inthe coordination sphere is fundamental in supramolecular

Hindawi Publishing CorporationAdvances in ChemistryVolume 2016 Article ID 5049718 8 pageshttpdxdoiorg10115520165049718

2 Advances in Chemistry

assembly [18ndash22] Hence the nature of these complexesdepends on the interplay between the metal ion the counterion and HMTA [23]

Within the scope of our ongoing research on the struc-ture and applications of coordination compounds basedon N- and NO-donor heterocyclic ligands and coligands(thiocyanate azide etc) we have synthesized a number ofdifferent materials and together with selected examples fromthe literature evaluated their antimicrobial properties [16 23ndash28]

The emergence of drug-resistant bacterial and fungalstrains has become a worldwide cause for concern [2930] This increasing resistance of microbes to antibacterialand antifungal drugs has necessitated the search for newcompounds to target pathogenic microbes [29 30] Severalefforts have been made to develop antimicrobial agents tofight against these resistant pathogens among which are theprotection of the efficacy and appropriate use of existingdrugs as well as research and development of new antimi-crobial agents that are not affected by the currently knownpredicted or unknown mechanisms of resistance [31ndash33]The incorporation of metals into antibacterial molecules isexpected to enhance the bactericidal or fungicidal propertiesof these drugs

In this work we report the synthesis and crystal struc-ture of a nickel(II) hexamethylenetetramine complex withthiocyanate coligand The biological activity of the complextowards some resistant pathogens evaluated using in vitroassays is also presented

2 Experimental

21 Materials NiSO4

sdot6H2

O hexamethylenetetramine andammonium thiocyanate were obtained from Sigma AldrichMethanol was obtained from Riedel-de Haen (Germany)The chemicals were of analytical grade and were used assuch while the solvent was distilled according to standardmethods

22 Synthesis of the Complex [Ni(HMTA)2

(NCS)2

(H2

O)2

]sdotH2

O A 15mL methanol solution of hexamethylenete-tramine (0280 g 20mmol) was added dropwise to a 15mLmethanolH

2

O (2 1 vv) solution of NiSO4

sdot6H2

O (0291 g1mmol) while stirring at room temperature After stirringfor 30 minutes ammonium thiocyanate (0156 g 2mmol) in10mL methanol was added into the solution The mixturewas further stirred for two hours and stored for a weekduring which time bluish-green needle-like crystals suitablefor single crystal X-ray diffraction were obtained They werefiltered washed with diethylether and dried over silica gel ina desiccator

23 Characterisation The infrared spectrum of the complexwas recorded using a Bruker ALPHA-P spectrophotometerdirectly on a small sample of the complex in the range 400ndash4000 cmminus1 while the UV-visible spectrum of an ethanolicsolution of the complex was recorded using a Bruker HACHDR3900UV-visible spectrophotometer at room temperature

24 X-Ray Crystal Structure Determination Intensity datafor the compound was collected using a Bruker AXS KappaAPEX II single crystal CCD Diffractometer equipped withgraphite-monochromated MoK120572 radiation (120582 = 071073 A)at room temperature The selected crystal for the diffractionexperiment had a dimension of 025 times 025 times 02mm3Accurate unit cell parameters were determined from thereflections of 36 frames measured in three different crystal-lographic zones by the method of difference vectorsThe datacollection data reduction and absorption correction wereperformed by APEX2 SAINT-Plus and SADABS programs[38] The structure was solved by direct methods procedureusing SHELXS-97 program [39] and the nonhydrogen atomswere subjected to anisotropic refinement by full-matrix leastsquares on 1198652 using SHELXL-97 program [39]The positionsof all the nonhydrogen atoms were identified from differenceelectron density map and were fixed accordingly Hydrogenatoms were treated by a mixture of independent and con-strained refinement

25 Antimicrobial Tests The in vitro antimicrobial activitiesof themetal saltsmetal complex ligands and reference drugswere evaluated by disk diffusion and broth microdilutionmethods The antimicrobial tests were carried out in theLaboratory of Phytobiochemical and Medicinal Plant StudyUniversity of Yaounde I Cameroon Four strains of bacteria(Salmonella enteric Shigella flexneri Escherichia coli andStaphylococcus aureus) and four strains of fungi (Candidaalbicans Candida krusei Candida parapsilosis and Candidaneoformans) were used for this study All the species werederived from stock cultures obtained from the MedicalBacteriology Laboratory of ldquoCentre Pasteur du CamerounrdquoYaounde Cameroon Chloramphenicol and fluconazole wereused as reference antibacterial and antifungal drugs respec-tively

251 Diffusion Tests In vitro antibacterial activities of theligand metal salt and the complex were evaluated usingdisc diffusion method Mueller-Hinton Agar was employedasmicrobial growthmediumThe antibacterial diffusion testswere carried out as previously reported [26]

Mueller-Hinton agar was prepared from a commerciallyavailable dehydrated base according to the manufacturerrsquosinstructions Several colonies of each microorganism werecollected and suspended in saline (09 NaCl) Thenthe turbidity of the test suspension was standardized tomatch that of a 05 McFarland standard (corresponding toapproximately 15 times 108 CFUmL for bacteria or 1 times 106to 5 times 106 cellsmL for yeast) Each compound or referencewas accurately weighed and dissolved in the appropriatediluents (DMSO at 10 methanol at 10 or distilledwater) to yield the required concentration (2mgmL forcompoundor 1mgmL for reference drug) using sterile glass-ware

Whatman filter paper number 1 was used to preparediscs approximately 6mm in diameter which were packedup with aluminum paper and sterilized by autoclavingThen25 120583L of stock solutions of compound or positive control was

Advances in Chemistry 3

delivered to each disc leading to 50120583g of compound or 25120583gof reference drug

The dried surface of a Mueller-Hinton agar plate wasinoculated by flooding over the entire sterile agar surfacewith 500120583L of inoculum suspensions The lid was left ajarfor 3 to 5 minutes to allow for any excess surface moistureto be absorbed before applying the drug impregnated discsDiscs containing the compounds or antimicrobial agentswere applied within 15 minutes of inoculating the MHAplate Six discs per Petri dish were plated The plates wereinverted and placed in an incubator set to 35∘CAfter 18 hours(for bacteria) and 24 hours (for yeasts) of incubation eachplate was examined The diameters of the zones of completeinhibition (as judged by the unaided eye) were measuredincluding the diameter of the disc Zones were measured tothe nearest whole millimeter using sliding calipers whichwas held on the back of the inverted Petri plateThree replicaswere performed for each sample and mean values of thegrowth inhibition zone were calculated Compounds wereconsidered active when the IZ was greater than 6mm

3 Results and Discussion

31 Synthesis of the Complex The reaction of hexamethylene-tetramine ammonium thiocyanate andNiSO

4

sdot6H2

Oyieldedthe complex [Ni(HMTA)

2

(NCS)2

(H2

O)2

]sdotH2

OThe complexwas bluish-green in colour and it was obtained in high yield74

32Description of theCrystal Structure Thecrystal structuraldata of the complex are summarized in Table 1 The ORTEPview of the crystal structure together with the atom num-bering scheme is shown in Figure 1 The packing diagramof the complex and the H-bonding scheme seen alongthe crystallographic b-axis are shown in Figures 2 and 3respectively Selected bond distances and bond angles for thecomplex are presented in Table 2

The complex crystallizes in themonoclinic crystal systemwith space group C2c The asymmetric unit consists ofone HMTA molecule one thiocyanate anion one coordi-nated water molecule one lattice water molecule and oneNi(II) ion The crystal structure of the complex revealsthat the Ni(II) coordination environment is a slightly dis-torted octahedron (NiN

4

O2

chromophore) in which it iscovalently bonded to two terminal HMTA N-atoms (Ni-N4 2238(2) A) in transaxial positions two water O-atoms(Ni-O1 2058(2) A) and two terminal NCSminus N-atoms (Ni-N22031(2) A) in the equatorial plane The Ni atom is locatedin an inversion centre This arrangement is similar to thatof related structures reported in the literature [35ndash37] TheNCSminus groups show almost linearity with N-C-S angle of17952∘ in the complex as previously reported for analogousCo and Mn structures [35ndash37] The connection between Niatoms andNCS groups is slightly bent with a Ni-N2-C8 angleof 17268∘ Furthermore the O atoms of both water moleculesand the N atoms of both NCSminus anions are each mutuallytrans to each other as evidenced by the bond angles O1-Ni-O1 180∘ and N2-Ni-N2 180∘ respectively Each lattice water

Table 1 Crystal data and structure refinement for the complex

Empirical formula C14

H32

N10

NiO4

S2

Formula weight 52733Temperature 100KWavelength (A) 120582 = 071073

Crystal system MonoclinicSpace group C2cUnit cell dimensions119886 (A) 18085(4)119887 (A) 74019(16)119888 (A) 17422(4)120572 (∘) 90120573 (∘) 91527(2)120574 (∘) 90

Unit cell volume 23314(9)119885 4119865(000) 11120Density (calculated) 1502Mgm3

Absorption coefficient 1054mmminus1

Crystal size 016 times 0203 times 0501mm3

Theta range for data collection 225 to 2815Indexes (ℎ 119896 119897)max (24 9 23)Reflections collected 6943Independent and observedreflections

2681[119877(int) = 00240]2563

Completeness to theta = 26∘ 998

Refinement method Full-matrix least squareson 1198652

Datarestraintsparameters 26810158Goodness-of-fit on 1198652 1051Final 119877 indices [119868 gt 2sigma(119868)] 119877

1

= 00269 1199081198772

= 00695

Final 119877 indices (all data) 119877

1

= 00279 1199081198772

= 00689

Largest diff peak and hole 0875 and minus0567 esdotAminus3

molecule forms three H-bonds with O-atom of a coordinatedwater molecule (O-Hsdot sdot sdotO 2669 A) noncoordinated N-atomofHMTA (O-Hsdot sdot sdotN2797 A) and S-atomof SCNminus (O-Hsdot sdot sdot S3310 A) There is another H-bond between the oxygen atomof the coordinated water molecule and a noncoordinatednitrogen of aHMTAmolecule (O-Hsdot sdot sdotNdistance = 2806 A)Adjacent Ni coordination centres are linked by free H

2

Omolecules via hydrogen bonds also involving two coordi-natedO-atoms of watermolecules and two uncoordinatedN-atoms of HMTAmolecule in the hydrogen bond net forming1D chains These adjacent chains are further connected toform 2D supramolecular layers parallel to the ac plane bySsdot sdot sdotN and Csdot sdot sdotC interactions The two-dimensional layersare further connected by O-Hsdot sdot sdot S and O-Hsdot sdot sdotN hydrogenbonds along the b crystallographic axis to form a three-dimensional supramolecular structure This is in agreementwith literature reports [35ndash37] The H-bonding motifs canbe described in Etterrsquos graph set notation as 1198772

2

(12) and


C11

C10

C12C7

C11

C13

S2

S2

C8O1

O1

O2

N5

N3

N4

N2

N2N6

N4

N3

N5

Ni1

N6

C13C9

C8

C9 C10

C7C12

Figure 1 ORTEP view of the complex with atom numbering scheme

NiSN

OCH

c

a

Figure 2 Packing diagram of the complex seen along the crystallo-graphic b-axis

119877

4

4

(16) [40 41] The nickel atoms form linear chains runningalong the b-direction with an interlayer Ni-Ni distance of7402 A while theNisdot sdot sdotNi distanceswithin hydrogen-bondedchains and between adjacent chains in the same layer are9465 A and 9771 A respectively

A comparison of the M-N (HMTA) M-N (NCSminus) andM-O (H

2

O) bond distances for similar structures foundin the literature [34ndash37] is shown in Table 3 The axialNi-N (HMTA) bond length is slightly shorter than thoseof Co-N and Mn-N but longer than that of Cu-N TheNi-N (NCSminus) bond length is similar to those of Co and Cubut is shorter than that of Mn The Ni-O bond is slightlyshorter than the other M-O bonds While the Ni complex

Table 2 Selected bond lengths (A) and angles (∘) for the complex

Ni1-O1 2058(2) N6-C7 1476(2)Ni1-N2 2031(2) N6-C10 1485(2)Ni1-N4 2238(2) N6-C12 1475(2)Ni1-O1 2058 S2-C8 1642(1)Ni1-N2 2031 N2-C8 1161(2)Ni1-N4 2238 N3-C7 1481(2)S2-C8 1642(1) N3-C9 1469(2)N2-C8 1161(2) N3-C11 1484(2)O1-Ni1-N2 9008 Ni1-N2-C8 17268O1-Ni1-N4 9373 Ni1-N4-C9 10874O1-Ni1-O1 180 Ni1-N4-C12 11334O1-Ni1-N2 8992 Ni1-N4-C13 11296O1-Ni1-N4 8627 S2-C8-N2 17952N2-Ni1-N4 9264 N4-Ni1-N4 180N2-Ni1-O1 8992 O1-Ni1-N2 9008N2-Ni1-N2 180 O1-Ni1-N4 9373N2-Ni1-N4 8736 N2-Ni1-N4 9264N4-Ni1-O1 8627 Ni1-N2-C8 17268N4-Ni1-N2 8736 Ni1-N4-C9 10874Ni1-N4-C13 11296 Ni1-N4-C12 11334

obtained has a unique coordination centre the complexes[Mn(hmt)

2

(H2

O)2

(NCS)2

]sdot[Mn(H2

O)4

(NCS)2

]sdot2H2

O and[Co(NCS)

2

(hmt)2

(H2

O)2

][Co(NCS)2

(H2

O)4

]sdotH2

O containtwo distinct six coordinate M(II) centres alongside twolattice water molecules and one lattice water moleculerespectively The independent uncharged components[M(NCS)

2

(hmt)2

(H2

O)2

] [M(NCS)2

(H2

O)4

] and H2

Oare linked together by three kinds of hydrogen bonds (O-Hsdot sdot sdotN O-Hsdot sdot sdotO and O-Hsdot sdot sdot S) to form a three-dimensionalsupramolecular structure [35ndash37] On the other hand thecoordination environment of the Cu atom in the complexK[Cu(C

6

H12

N4

)2

(NCS)3

]sdot2H2

O is trigonal bipyramidal with


Table 3 Comparison of bond parameters for similar structures [M(hmt)2

(H2

O)2

(NCS)2

] (M = Cu Co Mn and Ni)

M-N (HMTA) Bond length (A) M-N (NCSminus) Bond length (A) M-O (H2

O) Bond length (A) Ref

Cu-N 209(5)210(5) Cu-N

198(6)208(6)198(7)

None mdash [34]

Mn-N 24213(13) Mn-N 21342(15) Mn-O 21865(12) [35]Co-N 2341(5) Co-N 2058(5) Co-O 2104(5) [36]Co-N 23274(16) Co-N 20411(19) Co-O 21025(16) [37]Ni-N 2238(2) Ni-N 2031(2) Ni-O 2058(2) This work

Table 4 Relevant IR bands of the ligands and the complex

120592O-H 120592H2O 120592C-N 120592C-N (SCN) 120588CH2 120592M-O 120592M-N

HMTA mdash mdash 1238 mdash 810

Complex 3370 3250 1232 2084 821 778 683669

Figure 3 ORTEP representation of the H-bonding scheme of thecomplex seen along the crystallographic b-axis

three equatorial positions occupied by NCS groups and theaxial positions by the HMTA molecules [34]

As shown by Lu et al [37] the close distance of NCSminusgroups the large volume of HMTA ligand and the ratiobetween the divalent metal and NCSminus of 2 1 can probablyexplain the absence of Ssdot sdot sdot S Van der Waalsrsquo interactions inthe Mn [35] Co [36] and Ni (this work) complexes

33 Infrared Spectroscopy The characteristic IR band fre-quencies of the ligand and complexes are presented in Table 4

The broad band at 3250 cmminus1 and the sharp peak at1661 cmminus1 are assigned to 120592O-H and 120575H-O-H of lattice waterrespectively while the peak at 3370 cmminus1 is due to 120592O-Hof coordinated water [42] The CH

2

stretching vibrationalband of HMTA appears at 2957 cmminus1 The band at 1238 cmminus1assigned to the C-N stretch of HMTA is shifted to 1232 cmminus1in the complex while the band at 810 cmminus1 in the free ligandassigned to the CH

2

rocking vibration of HMTA is shiftedto 821 cmminus1 in the complex indicating coordination of theligand [27] The sharp peak at 2084 cmminus1 is assigned to the

ComplexHMTA RA

RBNH4SCN

0

4

8

12

16

20

24

28

32

NiSO4middot6H2O

A2 A3 A4 B1 B2 B3 B4A1

Figure 4 Histogram of inhibition zone of ligands metal salt andcomplex against bacteria

C-N stretching vibration of SCN [43] The appearance ofnew peaks at 778 cmminus1 683 cmminus1 and 669 cmminus1 respectivelyindicates M-O and M-N bonding between the metal and theligands

34 UV-Visible Spectroscopy The electronic spectrum of thenickel(II) complex exhibits two absorption bands one bandaround 25000 cmminus1 and a second broad and split band at15625ndash14514 cmminus1These bands have been assigned to 3A

2g rarr3T1g(P) and

3A2g rarr

3T1g(F) transitions respectively [44]

The ratio of 172 of the height of the first to that of thesecond band indicates an octahedral environment around thenickel(II) ion [45]

35 Antimicrobial Tests The metal salt ligands metal com-plex and reference drugs were tested for antimicrobialactivity in vitro against four bacteria and four fungi strainsThe susceptibility of the bacteria and fungi strains towardsthe compounds was judged by measuring the diameter of thegrowth inhibition zoneThe results are summarized in Table 5and displayed in a histogram (Figure 4)

HMTA was found to be active against three of theeight pathogens while the metal complexes showed increased


Table 5 Diameter of inhibition zone (mm) of the compounds against bacteria and fungi

A1

A2

A3

A4

B1

B2

B3

B4

Complex 9 plusmn 00 8 plusmn 00 10 plusmn 00 11 plusmn 00 8 plusmn 00 10 plusmn 00 9 plusmn 00 9 plusmn 00

HMTA 0 0 0 9 plusmn 14 0 85 plusmn 07 8 plusmn 00 0

NH4

SCN 6 plusmn 00 6 plusmn 00 0 6 plusmn 00 0 6 plusmn 00 0 0

NiSO4

sdot6H2

O 8 plusmn 00 7 plusmn 00 0 6 plusmn 00 7 plusmn 00 7 plusmn 00 8 plusmn 07 6 plusmn 00

RA 22 plusmn 00 20 plusmn 00 19 plusmn 14 20 plusmn 00 mdash mdash mdash mdashRB mdash mdash mdash mdash 30 plusmn 00 32 plusmn 00 22 plusmn 00 20 plusmn 00

A1

Staphylococcus aureusA2

Salmonella entericaA3

Shigella flexneriA4

Escherichia coli B1

Candida albicans B2

Candida parapsilosis B3

Candida kruseiB4

Candida neoformans RA reference antimicrobial (chloramphenicol) RB reference antifungal (fluconazole) mdash not tested

activity against all the pathogens This indicates that themetal ion probably plays an important role in enhancing theantimicrobial activity of the ligand on interaction with itThe highest activity of the complex is shown against E coliand S flexneri This increase in activity could be due to thereduction of the polarity of themetal ion by partial sharing ofthe positive charge with the ligandrsquos donor atoms so that thereis electron delocalisation within the metal complex Thismay increase the lipophilic character of the metal complexenabling it to permeate the lipid layer of the organism killingthem more effectively [46]

4 Conclusion

The synthesis of a nickel-HMTA complex [Ni(HMTA)2

(NCS)2

(H2

O)2

]sdotH2

O has been reported The equatorial H2

Oand NCS ligands coordinate in a nonlinear manner to thecentralmetal ionwhile the axialHMTA ligands are terminallycoordinated to the Ni(II) ion through one N-atom eachThe Ni(II) coordination environment is a slightly distortedoctahedron (NiN

4

O2

chromophore) An extended three-dimensional network is assembled via H-bonding interac-tions involving the lattice water molecule O-atom of a coor-dinated water molecule noncoordinated N-atom of HMTAand S-atomof SCNminus Results of the preliminary antimicrobialscreening against four pathogenic bacteria and four fungispecies indicate that the complex is moderately active withhighest activity shown against E coli and S flexneri Thecomplex could be further screened in vitro against a widerange of pathogens

Additional Points

CCDC 1452400 contains the supplementary crystallographicdata for the complex The data can be obtained free of chargefrom The Cambridge Crystallographic Data Centre viahttpssummaryccdccamacukstructure-summaryaccess=refereeampccdc=1452400ampauthors=che

Competing Interests

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

Acknowledgments

Theauthors thank theGovernment of Cameroon for financialsupport through the Fonds drsquoAppuis a la Recherche

References

[1] S Wohlert T Runcvski R E Dinnebier S G Ebbinghaus andC Nather ldquoSynthesis structures polymorphism and magneticproperties of transition metal thiocyanato coordination com-poundsrdquoCrystal Growth andDesign vol 14 no 4 pp 1902ndash19132014

[2] M J Zaworotko ldquoSuperstructural diversity in two dimensionscrystal engineering of laminated solidsrdquo Chemical Communica-tions no 1 pp 1ndash9 2001

[3] C Janiak ldquoEngineering coordination polymers towards appli-cationsrdquo Dalton Transactions no 14 pp 2781ndash2804 2003

[4] G R Desiraju ldquoCrystal engineering a holistic viewrdquo Ange-wandte ChemiemdashInternational Edition vol 46 no 44 pp8342ndash8356 2007

[5] C B Aakeroy N R Champness and C Janiak ldquoRecentadvances in crystal engineeringrdquo CrystEngComm vol 12 no 1pp 22ndash43 2010

[6] G R Desiraju ldquoCrystal engineering from molecule to crystalrdquoJournal of the American Chemical Society vol 135 no 27 pp9952ndash9967 2013

[7] L Carlucci G Ciani A Gramaccioli D M Proserpio andS Rizzato ldquoCrystal engineering of coordination polymers andarchitectures using the [cu(221015840-bipy)]2+ molecular corner asbuilding block (bipy=221015840-bipyridyl)rdquo CrystEngComm vol 2no 29 pp 154ndash163 2000

[8] S Stepanow N Lin and J V Barth ldquoModular assembly oflow-dimensional coordination architectures onmetal surfacesrdquoJournal of Physics Condensed Matter vol 20 no 18 Article ID184002 2008

[9] A M Kirillov ldquoHexamethylenetetramine an old new build-ing block for design of coordination polymersrdquo CoordinationChemistry Reviews vol 255 no 15-16 pp 1603ndash1622 2011

[10] M K Ammar T Jouini and A Driss ldquoSynthesis and struc-tural characterization of dihexamethylenetetraminetetraaquo-cobalt(II) hexaaquocobalt(II) sulfate hexahydraterdquo Journal ofChemical Crystallography vol 30 no 4 pp 265ndash268 2000

[11] A Ray J Chakraborty B Samanta et al ldquoTwo new hydrother-mally synthesised hexamine bridged LndashMndashL type coordinationpolymers characterisation and magneto-structural correla-tionrdquo Inorganica Chimica Acta vol 361 no 7 pp 1850ndash18602008


[12] Y Chen Y-L Wang S-M Ying and S-L Cai ldquoPoly[di-1205832

-chlorido-1205834

-hexa-methyl-ene-tetramine-bis-[chlorido(methanol-120581O)-cadmium(II)]]rdquo Acta Crystallographica Sec-tion E Structure Reports Online vol 63 no 11 Article IDm27512007

[13] A Trzesowska and R Kruszynski ldquoThe synthesis crystal struc-ture and thermal studies of a mixed-ligand 110-phenanthrolineand hexamethylenetetramine complex of lanthanum nitrateInsight into coordination sphere geometry changes of lan-thanide(III) 110-phenanthroline complexesrdquo Transition MetalChemistry vol 32 no 5 pp 625ndash633 2007

[14] X-L Li Z-S Lu and D-Z Niu ldquoBis(4-carboxypyridinium)aquapentakis(isothiocyanato-120581N)iron(III) bis(pyridinium-4-carboxylate)rdquo Acta Crystallographica Section E vol 63 no 11article m2640 2007

[15] D Chopra P Dagur A S Prakash T N Guru Row and MS Hegde ldquoSynthesis and crystal structure of M(hmt)

2

(H2

O)6

(NO3

)24

H2

O complexes where M = Mn2+ Co2+rdquo Journal ofCrystal Growth vol 275 no 1-2 pp e2049ndashe2053 2005

[16] M O Agwara M D Yufanyi J N Foba-Tendo M A Atambaand D T Ndinteh ldquoSynthesis characterisation and biologicalactivities of Mn(II) Co(II) and Ni(II) complexes of hexam-ethylenetetraminerdquo Journal of Chemical and PharmaceuticalResearch vol 3 no 3 pp 196ndash204 2011

[17] L S Miall and Mackenzie A Dictionary of Chemistry Long-mans 1956

[18] M K R Balan F N Ashok M Vasanthi R Prabu andA Paulraj ldquoMixed ligand complexes of Nickel(II) Copper(II)and Zinc(II) with nicotinanilide and thiocyanate with someNickel(II) Copper(II) And Zinc(II) saltrdquo International Journalof Life science and Pharma Reviews vol 3 no 2 pp L67ndashL752013

[19] D Fu-Tai Tuan J W Reed and R Hoffmann ldquoStudies ofthe linkage and bonding of triatomics in transition metalcomplexesmdashpart 2 NCSmdashcomplexesrdquo Journal of MolecularStructure THEOCHEM vol 232 pp 111ndash121 1991

[20] M Montazerozohori K Nozarian and H R Ebrahimi ldquoSyn-thesis spectroscopy theoretical and electrochemical studies ofZn(II) Cd(II) and Hg(II) azide and thiocyanate complexes of anew symmetric schiff-base ligandrdquo Journal of Spectroscopy vol2013 Article ID 718149 9 pages 2013

[21] S A Shaker Y Farina S Mahmmod andM Eskender ldquoZn (II)and Cd (II) mixed ligand complexes of 6-aminopurine theo-phylline and thiocyanate ion preparation and spectroscopiccharacterizationrdquo Journal of Engineering and Applied Sciencesvol 4 no 9 pp 29ndash33 2009

[22] E Czubacka R Kruszynski and T Sieranski ldquoThe structureand thermal behaviour of sodium and potassium multinuclearcompounds with hexamethylenetetraminerdquo Journal of Struc-tural Chemistry vol 23 no 2 pp 451ndash459 2012

[23] M O Agwara P T Ndifon and M K Ndikontar ldquoPhysic-ochemecal studies of some hexamethylenetetramine metal(II)complexesrdquo Bulletin of the Chemical Society of Ethiopia vol 18no 2 pp 143ndash148 2004

[24] M O Agwara P T Ndifon D M Yufanyi et al ldquoSynthesischaracterisation and crystal structure af a three-dimensionalnetwork of an H-bonded Ni(II) hexametylenetetramine com-plexrdquo Rasayan Journal of Chemistry vol 3 no 2 pp 207ndash2132011

[25] C D Tabong A M Ondoh D M Yufanyi and J FobaldquoCobalt(II) and zinc(II) complexes of hexamethylenetetramineas single source precursors for their metal oxide nanoparticlesrdquo

Journal of Materials Science Research vol 4 no 4 pp 70ndash812015

[26] A Colette AMOndoh DM Yufanyi andD S YanickGaelleldquoSynthesis crystal structure and antimicrobial properties of ananhydrous copper(II) complex of pyridine-2-carboxylic acidrdquoInternational Journal of Chemistry vol 7 no 1 pp 10ndash20 2014

[27] P T Ndifon M O Agwara A G Paboudam et al ldquoSyn-thesis characterisation and crystal structure of a cobalt(II)-hexamethylenetetramine coordination polymerrdquo TransitionMetal Chemistry vol 34 no 7 pp 745ndash750 2009

[28] A C B Yuoh M O Agwara D M Yufanyi M A CondeR Jagan and K O Eyong ldquoSynthesis crystal structure andantimicrobial properties of a novel 1-D cobalt coordinationpolymerwith dicyanamide and 2-aminopyridinerdquo InternationalJournal of Inorganic Chemistry vol 2015 Article ID 106838 8pages 2015

[29] J Tanwar S Das Z Fatima and S Hameed ldquoMultidrugresistance an emerging crisisrdquo Interdisciplinary Perspectives onInfectious Diseases vol 2014 Article ID 541340 7 pages 2014

[30] WHO Antimicrobial Resistance Global Report on SurveillanceWorld Health Organization Geneva Switzerland 2014

[31] B Spellberg R Guidos D Gilbert et al ldquoThe epidemic ofantibiotic-resistant infections a call to action for the medicalcommunity from the Infectious Diseases Society of AmericardquoClinical Infectious Diseases vol 46 no 2 pp 155ndash164 2008

[32] N Beyth Y Houri-Haddad A Domb W Khan and R HazanldquoAlternative antimicrobial approach nano-antimicrobial mate-rialsrdquoEvidence-BasedComplementary andAlternativeMedicinevol 2015 Article ID 246012 16 pages 2015

[33] V Kandi and S Kandi ldquoAntimicrobial properties ofnanomolecules potential candidates as antibiotics in theera of multi-drug resistancerdquo Epidemiology and Health vol 37Article ID e2015020 5 pages 2015

[34] J Pickardt ldquoThe crystal structure of potassium-bis(hexamethylenetetramine)-tris-(isothiocyanato) cuprate(II)-dihydrate K[Cu(C

6

H12

N4

)2

(NCS)3

] sdot 2H2

O a trigonalbipyramidal cupric complexrdquo Zeitschrift fur Naturforschung Bvol 36 no 5 pp 649ndash650 1981

[35] Q Liu B Li X Sun Z Xu and K Yu ldquoDiaquabis(hexamethyle-netetramine-N)bis(isothiocyanato)manganese(II) tetraaquabis(isothiocyanato)manganese(II) dihydraterdquo Acta Crystallogra-phica Section E Structure Reports Online vol 57 no 4 ppm151ndashm153 2001

[36] Y Zhang J Li H Xu H Hou M Nishiura and TImamoto ldquoStructural and spectroscopic properties of hex-amethylenetetramine cobalt(II) complex [Co(NCS)

2

(hmt)2

(H2

O)2

][Co(NCS)2

(H2

O)4

] (H2

O)rdquo Journal ofMolecular Struc-ture vol 510 no 1ndash3 pp 191ndash196 1999

[37] J Lu H-T Liu X-X Zhang D-Q Wang and M-JNiu ldquoImportant roles of weak interactions syntheses andsupramolecular structures of four CoIINiII-thiocyanato com-poundsrdquo Zeitschrift fur Anorganische und Allgemeine Chemievol 636 no 3-4 pp 641ndash647 2010

[38] Bruker in APEX2 SAINT-Plus and XPREP Eds Bruker AXSMadison Wis USA 2004

[39] G M Sheldrick ldquoA short history of SHELXrdquo Acta Crystallo-graphica Section A Foundations of Crystallography vol 64 no1 pp 112ndash122 2008

[40] M C Etter ldquoEncoding and decoding hydrogen-bond patternsof organic compoundsrdquo Accounts of Chemical Research vol 23no 4 pp 120ndash126 1990


[41] M C Etter J C MacDonald and J Bernstein ldquoGraph-setanalysis of hydrogen-bond patterns in organic crystalsrdquo ActaCrystallographica Section B Structural Science vol 46 no 2 pp256ndash262 1990

[42] C Hee Ng S Guan Teoh N Moris and S Yang Yap ldquoStruc-tural infrared spectral and thermogravimetric analysis of ahydrogen-bonded assembly of cobalt(II) and nickel(II) mixedcomplex cations with hexamethylenetetraamine and aqua lig-ands [M(hmt

)2

(H2

O)4

][M(H2

O)6

](SO4

)2

sdot6H2

Ordquo Journal ofCoordination Chemistry vol 57 no 12 pp 1037ndash1046 2004

[43] Y Zhang J Li M Nishiura and T Imamoto ldquoStructural spec-tral and thermal properties of a polymeric nickel(II) complexcontaining two-dimensional networkrdquo Journal of MolecularStructure vol 520 no 1ndash3 pp 259ndash263 2000

[44] F E Mabbs and D J MachinMagnetism and Transition MetalComplexes Chapman and Hall London UK 1973

[45] F A Cotton and G Wilkinson Advanced Inorganic ChemistryA Comprehensive Text Interscience Publishers New York NYUSA 4th edition 1980

[46] Z H Chohan A Munawar and C T Supuran ldquoTransitionmetal ion complexes of Schiff-bases Synthesis characterizationand antibacterial propertiesrdquo Metal-Based Drugs vol 8 no 3pp 137ndash143 2001

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


assembly [18ndash22] Hence the nature of these complexesdepends on the interplay between the metal ion the counterion and HMTA [23]

Within the scope of our ongoing research on the struc-ture and applications of coordination compounds basedon N- and NO-donor heterocyclic ligands and coligands(thiocyanate azide etc) we have synthesized a number ofdifferent materials and together with selected examples fromthe literature evaluated their antimicrobial properties [16 23ndash28]

The emergence of drug-resistant bacterial and fungalstrains has become a worldwide cause for concern [2930] This increasing resistance of microbes to antibacterialand antifungal drugs has necessitated the search for newcompounds to target pathogenic microbes [29 30] Severalefforts have been made to develop antimicrobial agents tofight against these resistant pathogens among which are theprotection of the efficacy and appropriate use of existingdrugs as well as research and development of new antimi-crobial agents that are not affected by the currently knownpredicted or unknown mechanisms of resistance [31ndash33]The incorporation of metals into antibacterial molecules isexpected to enhance the bactericidal or fungicidal propertiesof these drugs

In this work we report the synthesis and crystal struc-ture of a nickel(II) hexamethylenetetramine complex withthiocyanate coligand The biological activity of the complextowards some resistant pathogens evaluated using in vitroassays is also presented

2 Experimental

21 Materials NiSO4

sdot6H2

O hexamethylenetetramine andammonium thiocyanate were obtained from Sigma AldrichMethanol was obtained from Riedel-de Haen (Germany)The chemicals were of analytical grade and were used assuch while the solvent was distilled according to standardmethods

22 Synthesis of the Complex [Ni(HMTA)2

(NCS)2

(H2

O)2

]sdotH2

O A 15mL methanol solution of hexamethylenete-tramine (0280 g 20mmol) was added dropwise to a 15mLmethanolH

2

O (2 1 vv) solution of NiSO4

sdot6H2

O (0291 g1mmol) while stirring at room temperature After stirringfor 30 minutes ammonium thiocyanate (0156 g 2mmol) in10mL methanol was added into the solution The mixturewas further stirred for two hours and stored for a weekduring which time bluish-green needle-like crystals suitablefor single crystal X-ray diffraction were obtained They werefiltered washed with diethylether and dried over silica gel ina desiccator

23 Characterisation The infrared spectrum of the complexwas recorded using a Bruker ALPHA-P spectrophotometerdirectly on a small sample of the complex in the range 400ndash4000 cmminus1 while the UV-visible spectrum of an ethanolicsolution of the complex was recorded using a Bruker HACHDR3900UV-visible spectrophotometer at room temperature

24 X-Ray Crystal Structure Determination Intensity datafor the compound was collected using a Bruker AXS KappaAPEX II single crystal CCD Diffractometer equipped withgraphite-monochromated MoK120572 radiation (120582 = 071073 A)at room temperature The selected crystal for the diffractionexperiment had a dimension of 025 times 025 times 02mm3Accurate unit cell parameters were determined from thereflections of 36 frames measured in three different crystal-lographic zones by the method of difference vectorsThe datacollection data reduction and absorption correction wereperformed by APEX2 SAINT-Plus and SADABS programs[38] The structure was solved by direct methods procedureusing SHELXS-97 program [39] and the nonhydrogen atomswere subjected to anisotropic refinement by full-matrix leastsquares on 1198652 using SHELXL-97 program [39]The positionsof all the nonhydrogen atoms were identified from differenceelectron density map and were fixed accordingly Hydrogenatoms were treated by a mixture of independent and con-strained refinement

25 Antimicrobial Tests The in vitro antimicrobial activitiesof themetal saltsmetal complex ligands and reference drugswere evaluated by disk diffusion and broth microdilutionmethods The antimicrobial tests were carried out in theLaboratory of Phytobiochemical and Medicinal Plant StudyUniversity of Yaounde I Cameroon Four strains of bacteria(Salmonella enteric Shigella flexneri Escherichia coli andStaphylococcus aureus) and four strains of fungi (Candidaalbicans Candida krusei Candida parapsilosis and Candidaneoformans) were used for this study All the species werederived from stock cultures obtained from the MedicalBacteriology Laboratory of ldquoCentre Pasteur du CamerounrdquoYaounde Cameroon Chloramphenicol and fluconazole wereused as reference antibacterial and antifungal drugs respec-tively

251 Diffusion Tests In vitro antibacterial activities of theligand metal salt and the complex were evaluated usingdisc diffusion method Mueller-Hinton Agar was employedasmicrobial growthmediumThe antibacterial diffusion testswere carried out as previously reported [26]

Mueller-Hinton agar was prepared from a commerciallyavailable dehydrated base according to the manufacturerrsquosinstructions Several colonies of each microorganism werecollected and suspended in saline (09 NaCl) Thenthe turbidity of the test suspension was standardized tomatch that of a 05 McFarland standard (corresponding toapproximately 15 times 108 CFUmL for bacteria or 1 times 106to 5 times 106 cellsmL for yeast) Each compound or referencewas accurately weighed and dissolved in the appropriatediluents (DMSO at 10 methanol at 10 or distilledwater) to yield the required concentration (2mgmL forcompoundor 1mgmL for reference drug) using sterile glass-ware

Whatman filter paper number 1 was used to preparediscs approximately 6mm in diameter which were packedup with aluminum paper and sterilized by autoclavingThen25 120583L of stock solutions of compound or positive control was






4

sdot6H2


2

(NCS)2

(H2

O)2

]sdotH2




4

O2




H32

N10

NiO4

S2







2681[119877(int) = 00240]2563




1

= 00269 1199081198772

= 00695


1

= 00279 1199081198772

= 00689



2


2

(12) and


C11

C10

C12C7

C11

C13

S2

S2

C8O1

O1

O2

N5

N3

N4

N2

N2N6

N4

N3

N5

Ni1

N6

C13C9

C8

C9 C10

C7C12


NiSN

OCH

c

a


119877

4

4



2





2

(H2

O)2

(NCS)2

]sdot[Mn(H2

O)4

(NCS)2

]sdot2H2

O and[Co(NCS)

2

(hmt)2

(H2

O)2

][Co(NCS)2

(H2

O)4

]sdotH2


2

(hmt)2

(H2

O)2

] [M(NCS)2

(H2

O)4

] and H2


6

H12

N4

)2

(NCS)3

]sdot2H2




(H2

O)2

(NCS)2




Cu-N 209(5)210(5) Cu-N

198(6)208(6)198(7)

None mdash [34]





Complex 3370 3250 1232 2084 821 778 683669






2


2


ComplexHMTA RA

RBNH4SCN

0

4

8

12

16

20

24

28

32

NiSO4middot6H2O

A2 A3 A4 B1 B2 B3 B4A1




2g rarr3T1g(P) and

3A2g rarr







A1

A2

A3

A4

B1

B2

B3

B4



NH4


NiSO4

sdot6H2



A1



Shigella flexneriA4

Escherichia coli B1

Candida albicans B2


Candida kruseiB4



4 Conclusion


(NCS)2

(H2

O)2

]sdotH2



4

O2


Additional Points


Competing Interests


Acknowledgments


References














-chlorido-1205834





2

(H2

O)6

(NO3

)24

H2






















6

H12

N4

)2

(NCS)3

] sdot 2H2




2

(hmt)2

(H2

O)2

][Co(NCS)2

(H2

O)4

] (H2









)2

(H2

O)4

][M(H2

O)6

](SO4

)2

sdot6H2















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of






4

sdot6H2


2

(NCS)2

(H2

O)2

]sdotH2




4

O2




H32

N10

NiO4

S2







2681[119877(int) = 00240]2563




1

= 00269 1199081198772

= 00695


1

= 00279 1199081198772

= 00689



2


2

(12) and


C11

C10

C12C7

C11

C13

S2

S2

C8O1

O1

O2

N5

N3

N4

N2

N2N6

N4

N3

N5

Ni1

N6

C13C9

C8

C9 C10

C7C12


NiSN

OCH

c

a


119877

4

4



2





2

(H2

O)2

(NCS)2

]sdot[Mn(H2

O)4

(NCS)2

]sdot2H2

O and[Co(NCS)

2

(hmt)2

(H2

O)2

][Co(NCS)2

(H2

O)4

]sdotH2


2

(hmt)2

(H2

O)2

] [M(NCS)2

(H2

O)4

] and H2


6

H12

N4

)2

(NCS)3

]sdot2H2




(H2

O)2

(NCS)2




Cu-N 209(5)210(5) Cu-N

198(6)208(6)198(7)

None mdash [34]





Complex 3370 3250 1232 2084 821 778 683669






2


2


ComplexHMTA RA

RBNH4SCN

0

4

8

12

16

20

24

28

32

NiSO4middot6H2O

A2 A3 A4 B1 B2 B3 B4A1




2g rarr3T1g(P) and

3A2g rarr







A1

A2

A3

A4

B1

B2

B3

B4



NH4


NiSO4

sdot6H2



A1



Shigella flexneriA4

Escherichia coli B1

Candida albicans B2


Candida kruseiB4



4 Conclusion


(NCS)2

(H2

O)2

]sdotH2



4

O2


Additional Points


Competing Interests


Acknowledgments


References














-chlorido-1205834





2

(H2

O)6

(NO3

)24

H2






















6

H12

N4

)2

(NCS)3

] sdot 2H2




2

(hmt)2

(H2

O)2

][Co(NCS)2

(H2

O)4

] (H2









)2

(H2

O)4

][M(H2

O)6

](SO4

)2

sdot6H2















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


C11

C10

C12C7

C11

C13

S2

S2

C8O1

O1

O2

N5

N3

N4

N2

N2N6

N4

N3

N5

Ni1

N6

C13C9

C8

C9 C10

C7C12


NiSN

OCH

c

a


119877

4

4



2





2

(H2

O)2

(NCS)2

]sdot[Mn(H2

O)4

(NCS)2

]sdot2H2

O and[Co(NCS)

2

(hmt)2

(H2

O)2

][Co(NCS)2

(H2

O)4

]sdotH2


2

(hmt)2

(H2

O)2

] [M(NCS)2

(H2

O)4

] and H2


6

H12

N4

)2

(NCS)3

]sdot2H2




(H2

O)2

(NCS)2




Cu-N 209(5)210(5) Cu-N

198(6)208(6)198(7)

None mdash [34]





Complex 3370 3250 1232 2084 821 778 683669






2


2


ComplexHMTA RA

RBNH4SCN

0

4

8

12

16

20

24

28

32

NiSO4middot6H2O

A2 A3 A4 B1 B2 B3 B4A1




2g rarr3T1g(P) and

3A2g rarr







A1

A2

A3

A4

B1

B2

B3

B4



NH4


NiSO4

sdot6H2



A1



Shigella flexneriA4

Escherichia coli B1

Candida albicans B2


Candida kruseiB4



4 Conclusion


(NCS)2

(H2

O)2

]sdotH2



4

O2


Additional Points


Competing Interests


Acknowledgments


References














-chlorido-1205834





2

(H2

O)6

(NO3

)24

H2






















6

H12

N4

)2

(NCS)3

] sdot 2H2




2

(hmt)2

(H2

O)2

][Co(NCS)2

(H2

O)4

] (H2









)2

(H2

O)4

][M(H2

O)6

](SO4

)2

sdot6H2















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



(H2

O)2

(NCS)2




Cu-N 209(5)210(5) Cu-N

198(6)208(6)198(7)

None mdash [34]





Complex 3370 3250 1232 2084 821 778 683669






2


2


ComplexHMTA RA

RBNH4SCN

0

4

8

12

16

20

24

28

32

NiSO4middot6H2O

A2 A3 A4 B1 B2 B3 B4A1




2g rarr3T1g(P) and

3A2g rarr







A1

A2

A3

A4

B1

B2

B3

B4



NH4


NiSO4

sdot6H2



A1



Shigella flexneriA4

Escherichia coli B1

Candida albicans B2


Candida kruseiB4



4 Conclusion


(NCS)2

(H2

O)2

]sdotH2



4

O2


Additional Points


Competing Interests


Acknowledgments


References














-chlorido-1205834





2

(H2

O)6

(NO3

)24

H2






















6

H12

N4

)2

(NCS)3

] sdot 2H2




2

(hmt)2

(H2

O)2

][Co(NCS)2

(H2

O)4

] (H2









)2

(H2

O)4

][M(H2

O)6

](SO4

)2

sdot6H2















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



A1

A2

A3

A4

B1

B2

B3

B4



NH4


NiSO4

sdot6H2



A1



Shigella flexneriA4

Escherichia coli B1

Candida albicans B2


Candida kruseiB4



4 Conclusion


(NCS)2

(H2

O)2

]sdotH2



4

O2


Additional Points


Competing Interests


Acknowledgments


References














-chlorido-1205834





2

(H2

O)6

(NO3

)24

H2






















6

H12

N4

)2

(NCS)3

] sdot 2H2




2

(hmt)2

(H2

O)2

][Co(NCS)2

(H2

O)4

] (H2









)2

(H2

O)4

][M(H2

O)6

](SO4

)2

sdot6H2















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



-chlorido-1205834





2

(H2

O)6

(NO3

)24

H2






















6

H12

N4

)2

(NCS)3

] sdot 2H2




2

(hmt)2

(H2

O)2

][Co(NCS)2

(H2

O)4

] (H2









)2

(H2

O)4

][M(H2

O)6

](SO4

)2

sdot6H2















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




)2

(H2

O)4

][M(H2

O)6

](SO4

)2

sdot6H2















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, Crystal Structure, and...

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Transcript of Research Article Synthesis, Crystal Structure, and...