367 Makalah PendamPing Kimia SI{-I3FS il 13 Maret 2010Paralel F

STRUCTURALANDMAGNETICPRoPERTIESoTC00RDINATIoNP0LYMERlfe(prc)rllliCr(oxhl

Fahimah Martakl, Di ulia onggor, Ismunandart, Agung Nugroho2, Ibrahim Baba3'

Nandang Mufti*

llnorganic and Physical Chemistry Group' ITB' Indonesia

Email : fahima-riza@Yahoo'com

2 physics of lvtagn*ir* uidTh6iiri"E-*iarch Group, ITB, Indonesia

: S"toofoiCfr'emi"al Sciences and Technology, UKM, Malaysia

+ i*iilnstitute of Advanced Materials, RuG, The Netherlands

AbstractA polymer complex with formula of [Fe(pic)5]iLic.(o*)rl _tn-1c

: picolinic acid, ox=oxalate) has been

prepared from direct ,;i." ;i sotution'or'iii"i*ri. @iI) tet ugoorouorate and tris(oxalate) lithium

chromate(IlD under nitrogen atmospher€- characterization ofthe complex was made by microanalyses' FT-

IR spectroscop,, x-ray iimu.tion- and magpetometer. The polymei structur€ of the complex has been

determined and refined using Le Bail method,'it "tyt"ffi*t in a cubic structure ylttr yace group of P213'

a:,5.2840(18) andf-+. fiemagnetic properties of the complex has been studied in the temperature range

between 5 to 300 r. rne .f*.tiri moment "i;J u, *a c*i" weiss temperature of 7 '13 K are obtained

from correlation between magnetic susceptibilifr u!tt* ,.rperatur' This indicates that the complex has a

ferromagnetic interaction and suggests tfr" -ud"ti" mo-""t'a'" dominated by ion iron(ID in the high spin

state.

Keywords: complex polymer, crystal structure' ferromagtetic interaction

ii

IntroductionThe field of research based on

molecule-based magnets has e*p"T!:n-c*

remarkable growth in the past decade --" lt ts

"o* well--recognized that coordination

compounds are ldeal building blocks. for a,rtiity of solid state materials including

noom temperature magnets' One of most

fertite *"* in molecular magnetism is

transition-metals oxalato complexes'. a

"*r.qu"n.e of the fact that the oxalato

bridge promotes magnetic coupling between

paramagnetic metal centers'r-'- Ifrolecular based magnet with formula

AM0M([I)(Czoq)r] (A:--5.: --{(*c,n)of,' gNi*cin'lf, [N(n-c5H11)a]*'

fPt Crn lli; M(IIF Mn" Fe' Cu' Co' Zn

Li r"r: f", ct has been ieported u-'o' These

crmpoonds have shown to behave as ferro or

ferrimagnet properties with critical

temperatures ranging from 6- ty . aa K'

Int"t*ot"",rlar intiractions in the bimetallic

compounds are in general very-weak.and as

,".oit tU" critical timperature, Tc, is limited

to low temperature. Thereby, the idea oftransition-mital complex insertion on the

1U'U1ox;31'- building block is a reasonably

synthesis strateg1l-

The use of tris(bipyridil) complex

cation, tz([)(bpy[]2. ( Z(D = Fe, Co, Ni'n"l n, fvriUp<C<m)(ox)31- havg led to the

fo.rnutioo ' of three-dimensional network

iZiiiltupvXltM(tr)c(c(tu)(9x):ltclo4l, it

;;;6;tda by coronado"' These three-

dimensional compound behave also as ferro

*J t"tti*agnet but with lower ordering

temperatur -than their two-dimensional

analogues. However, Sieber .and Hauserl2

[p"tt"O that [Co(bpy) d2* which normally

high spin ground state when

irlotpotut"d in the oxalate network'

{tco(bpv) rlll-(DCr(Illxoxhl}, becomes a

spin crossover system.

In the Present PaPer the PolYmeric

complex that obtained by - combining the

**rl"* cation [Fe(picolinic)3]'* with the

ii<inXo*l l'- and t i(aq) is presented'

fn" pt*p*"tion, structural characterization

*a Lugn"tic study of the compound of

formula- [Fe{picolinic)3]tli(I)C(mXox):lhas reported.

2. ExPeriment2.l Matcrials

All chemicals were of reagent grade

and were used as commeroially obtained'

368 Makalah Pend:rmping Kimia

Standard literature proceduresl3 wereysed to prepare the staring materialsKs [Cr(CzO+):].3F{zO, A&[C(CuOa)3].2H2O.

2.2 fnstrumentsMetal content was determined by

Absorpfion Atomic Spectroscopy ShimadzuAA8801S. Elemental analyses (C, H, N)were performed on Fison EA I l0gmicroanalytical analyzer at UniversityKebangsaan Malaysia. The FT-IR spectrawas recorded on Shimadzu FTIR_g400spectrometer in the 4000 - 400 cm'r spectralregions. Powder x-ray diffractionmeasurements was performed philips pW1835 Difractometer using Cu Ko radiation, atAustralian National Beamline, Japan.Magnetic susceptibility measurements( 5-300 K ) were carried out using a euantumDesign MPMSR-2 5T SeUID magnetometer(measurements carried out at 1000 Oe)performed at Groningen University, TheNederlands.

2.3 Synthesis of [Fe(pic)31 [LiCr(ox)31Polymeric Complex

Complexes of [Fe(pic)3][BFa]2 andAgr[C(ox)3] were prepared to used asprecursor to produce [Fe(pic)3][LiC(oxhJ.

Synthesis of [Fe(pic)3|[BFnlz complexTo a solution of Fe(BFa)2.6HzO (0.34

g, I mmol) in 3 mL methanol, a hot solutionof picolinic acid (0.39 g,3.21mmol ) in 10mL of methanol was added. The reactionmixture was heated at 70-80 oC under Nz gasfor 30 min. A red precipitate appeared wasfiltered out, and dried over paoro.

Synthesis of Ag[Cr(ox)31 complexTo an aqueous solution of

K3[C(ox)3].3HzO (0.a9 g I mmol) in 5 mLof water, a solution of AgNO3 (0.51 gram, 3mmol) in 5 mL of water was added. Thereaction mixture was stirred for 30 min underambient temperature. The dark violet crystalsappeared was filtered out, and dried overP+Oro.

Synthesis of [Fe(pic)31 [LiCr(ox[] complexTo suspension of Ag[C(ox]l (0.34

gram, 0.5 mmol) in l0 mL methanol wasadded a solution of LiCl (0.063 gram, 1.5rnmol) in the same solvent (3 mL). The white

SII-!F!I II 13 Maret 20lOParalel F

precipitate AgCl was filtered out. The gre€trsolution obtained was added to solution of[Fe(pich][BF4]2 (0.30 gram, 0.5 mrnol) in 5mL water. The red precipitate was filtered

. . and dried over PcOro.

3. Result and l)iscussion3.1 Synthesis of [Fe(pic)31 [LiCr(ox)31

Polymeric ComplexThe coordination polymer

t{e(nrc):ltLiC(ox)31 was synthesised by *readdition of a solution of the iron(U) picotiniccation in water to a sotution of the tris_oxalate chrome complex with an excess ofmonovalent metal lithium. The compordwas obtained as red microcrystals in 69.6S% yield.

The general synthetic pathway for ttecomplexation reaction taking place, may berepresented as follows.

Ks[C(ox):] (aq) * 3AgNO3 (aq) -)Ag[Cr(ox[] t,t + 3 KNO3 1uq;

Ag[C(ox)3] cr,r^",ourl + 3LiCl (Metorf-+ [LiC(ox)rJ'{n.,or1 + 3AgCl cl

[Fe(pic)s]2i"qi + [LiC(ox)r]2inr",orn[Fe(pic)3] piCr(ox]l

1,1

This compound is Stable in air and is solublein some organic solvent are dimetilformamida and dimetil sulfoxida, but attemtsto obtain single crystal suitable for x-raystructure determination, has so far beenunsuccesfull. However, the polymercomplex was further characterized on thebasis of the following results. The formulaof the complex was resulted from elementalcontends has been listed in Table l.

The formula of the compound wasalso supported by infrared spectrum. Thespectmm of the complex is shown in Figurel. The absorbtion peak at 3429 cm-l wasindicated a streching vibration of OH fromligand picolinic. Streching vibration CHaromatic ring is shown at 3109 cmr-Streching vibration C:O from carboxil'ategroyp shifted to higher frequency of l7l3cm-', which indicates that it has been affectedupon coordination to metal ion. At the sarretime, v(CO) streching at 1080 cm-ris shiftedto lower frequency suggest the weakeningof v(CO) and formation of stronger bond

i.$

I

Table 1. The metal ion and c, H and N contents of polymer complex

369 Makalah PendamPing Kimia

benveen Fe-O. The strongest shift is

observed for v(C:N) bands of pyridin ring at

1597, which is a proof fo direct bonding ofpyridine nitrogen atom to the iron(Il) ' The

The presence ofband at frequency 455

ctrn-r is due to streching vibration Fe-O'

Another band appeared in spectra of the

complex at 416 cml attributed v(Cr-O), itindiiates that the oxygen atom in oxalate-

bridged Soup coordinate to metal from the

chrome atom.The powder X-ray difraction pattern

of [Fe(pic)r][LiC(ox)r] showed that the

compound has a cubic cell. The space group

of [Fe(pic]l[LiC(ox[] derived from the

Rietica program was P213, a=15.2840(18) Aaad Z=4. Typical Le Bail plot are shown in

SN'IIPK II 13 Maret 2010Paralel F

bands at frequencY 1380 and 810 cm-'

indicated oxalate as bridge liganra. Streching

vibration Fe-N was been obserued at 513 cm-''

Figure 2. The model of the structure of the

Rietveld refinement was built by reference to

that of tco(bpy)sltliC(ox)rl. In this model,

the compound consists of three-dimensional

oxalate back-bone, which provides perfect

cavities with regard to size and geometry forthe [Cotr(bpy)3]2* ions. The site symmetry ofboth the both the tris-oxalate as well as tris-

bipyridyl complexes is C3. The rather loose

oiutat" network is stabilised by the tris-

bipyridil complexes through electrostatic

interactions from n-overlap between oxalate

and bipyridine along the trigonal axis'

105.0

$T

100.0

9s.0

90.0

85. 0

80.0

75-O

3500.0 3000.o 2500-0 2qoo.o 1?50'O 1500'0 L250-0rrrn Sgrt a.DZU 8400 ZUL : FAI{Ir4AH1 { 13 -12-06 )

500. o1y'cm4000,0

- scan

[Fe(pic)3][LiCr(ox[]

* Calculated

1 '2 I zszt'g

I ',[n,.,152715

o

Figure 1. The IR spectrum of [Fe(pic)3][Lic(ox):J

370 Makalah Pendamping Kimia

IFe(pic)3][LiCr(CzOa)a]

3,m0

2,m

?ru

1,Sm

1,m0

flto

0

-ffi

ffi? thete {deg}

Figure 2. I* ryI refinement plot showing the observed (+;. Calculated (solid line) and difgr x-ft powder pattern diffraction profile of ;r"1pi"1rltlic(ox):1. rrr"-ti"tshow the positions of the allowed Bragg reflecyions in rpu"i grrup irir3.

3.2. Magnetic Pnoperties of[re(pic)d[LiCr{ox)3|

(Itc3ot>

The magnetic behaviour of compoundfFe(pic)d[LiC(ox]l under the form of I,and l/26y versus T plots is shown in Figure 3.The X value remains almost constant down to100 K while cooling down from 300 K andstarts to increase below 100 K followed by arapid increase rapidly below 40 K. In ihetemperature region 100 K < T < 300 K, 76values obey the Curie-Weiss law

C(Z= )h + , U"*).

The Tr:r, obtained

for the compound is 7.13 K with C = 4.06emu K mol'r. The positiv T6p valuesindicates the near neighbor magneticexchange interaction in the compound isferromagnetic. At.room temperature 26yT is3.89 emu K mol-r, which lower than thatexpected for magnetic interaction betweenFe(tI) and Cr(Itr) ions (4.96 emu K mol-r).

Upon coolingdecreases, reaching a3.48 emu K mol-r.

26MTminimum vahe

0.7

6o ocoE> 0.3Fo{0

0.6

05

0.1

0.0

o 40 80 1m i6o 2oo 240 2e sCD

T (K)

Figure 3. Temperature dependence of 61fr[Fe(pic)3][LiC(ox):]

37 1 Makalah PendamPing,Kimia SI*-KPK IL 13 Maret 2010Paralel F

Oxalate Dianion), . InorganicChenristry, 40, 113 * 120.

Coronado, E., Gal6n-Mascar6s, J. R',

G6mez-Garcia, C. J., and Martinez-Agudo, J. M., Martinez-Ferero, E., 2001,

Layered , Molecule-Based Magnets

Formed by DecamethylmetalloceniumCations and Two-Dimensional BimetallicComplexes {lMtrRultr(ox)3] (Mtr =Mn,Fe, Co, Cu and Zn; ox = oxalate/,

. Journal of Solid State Chemistry, 159,

391- 402.Pointillart, F;, Train, C. , Gr.ucelle, M.,

Villain, F., Decutins, S. and Verdagueq

M., 2004, Chiral Terlplating Activity ofTris(bipyridine)ruthenium(Il) Cation in

. the Design of Three-Dimensional (3D)

Optically Active Oxalate-Bridged

{ tRu(bpy)rl[Cu2"l'Ii211-.(Czon):i ]n (0 < x< 1; bpy o 2,2'-bipyridine): Structural,

Optical, and }vtragnetic Studies, Chemicul

Material,' 16, 832-841.

Coronado, E., Gali{n-Mascar6s, J:R.,' G6mez-

Garcia,:C. J', Marti-Gastaldo, C., 2005'

Synthesis,' Stnrcture, and Magaetic

Pioperties of the Oxalate-Based

Bimetallic Ferromagneti Chain {tK(18-crown-6)lMn(Hzo)zCr(ox):l)* (18-

crown-6 = Cr2H;o6, oi = Czof),Inorg*tic C.hemisW, 44, 6197'5202'

Coronado, 8.,'Gal6n-Mascar6s, J'R', :Marti-

Gastaldo, C., 2006, 'sYnthesis and

Characterization of a Soluble BimetallicOxalate-Based Bidemensional Magnet:

[K( I 8-crown-6)]: Mni(HzO)a {Cr(ox)3 } 31,

Inorganic ChemistrY,4s, 1882- I 884'

Ovanesyan , N. S., Shilov, G.V., Pyalling, A'A., Train C., Gredin, P', 2A04,

Structural and Magnetic Properties ofTwo- and Three-dimensional Molecule-

Based Magnets (catfttrntrU'o(CrOo)ul-,

Jonrnal of Magnetism and Magnetic

Materials, 212'27 6, 1 089- I 090.

Coronado E., Gal6n-Mascar6s, J'R',

Cimenez-Saiz, C-, G6mez-Garcia, C'J',

2003, Magnetic Properties of HybridMolecular Materials Based on Oxalato

Complexes, P olyhedron, 22, 2381-2386'

Pellaux, R., Schmalle, W. H., Huber, R',

Fischer, P., Hauss, T., Ouladdiaf,El., and

Decurtins, S., 1997, Molecular-BasedMagnetism in Bimetallic Two-Dimensional Oxalate-Bridged Networks'

T(K}

Figure 4. Fitting the plot of molar magnetic

suscePtibilitY vs temperatur for

tFe(pic)d[LiCr(ox):] :

ConclusioasThe polymeric complex of fonnula

[Fe(pic[]tlicr(ox)d has bsen synthesized'

FormuU of the complex has been supaorted

by metal ion contents, the elemental C,, H, Ndata, ff-m spectra in 400 - 4000 cm-'' The

crystal structure was anBlyzed by Rietveld

*Lthod with the powder X-ray diffraction

data. The space group of the compound is

Y2$. From the results of magrretic

rneasurement for [Fe(pic)r] [LiC(ox):], it was

the comPound show ferromagnetic

behaviour.

AcknowledgmentAuthors thank for financial support

from Direktorat Jendral Pendidikan

Tinggi (Dikti), Research Grant No'

SZaSPPPPP/DP2M/IU2006, as well as

Program Studi Kimia Institut Teknologi

Bariclung, University Kebangsaan Malaysia

for providing t'acilities and support to the

success ofthe studY.

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