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Study on metal complexes of chelating resins bearingiminodiacetate groups

Ecaterina Stela Dragan a,*, Maria Valentina Dinu a, Gabriela Lisa b, Andrzej W. Trochimczuk c

a ‘‘Petru Poni” Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi, Romaniab ‘‘Gh. Asachi” Technical University, Department of Chemical Engineering, Mangeron Avenue 71, 700050-Iasi, Romaniac Faculty of Chemistry, Wroclaw University of Technology, Wyspianskiego 27, 50- 370 Wroclaw, Poland

a r t i c l e i n f o

Article history:Received 9 February 2009Received in revised form 13 March 2009Accepted 19 March 2009Available online 27 March 2009

Keywords:Chelating resinsPolymer-metal complexesFT-IR spectroscopyThermogravimetric analysisElectron paramagnetic resonance

a b s t r a c t

Cu(II), Co(II) and Ni(II) complexes of chelating resins (CR) bearing iminodiacetate (IDA)ligands were prepared. The CR-metal complexes were characterized by FT-IR spectroscopy,X-ray diffraction (XRD), thermal behavior (TG and DTG) under nitrogen atmosphere, andelectron paramagnetic resonance (EPR). FT-IR spectra of the CR-metal complexes showedthe characteristic bands of CR were still present but red-shifted after the metal complexa-tion, and new bands assigned to Me–N bonds were observed. Thermal behavior of themetal-CR complexes supported the metal complexation, metal complexation leading tothe decrease of the thermal stability of the CR, the lowest thermal stability being foundwhen the highest amount of Cu(II) was loaded. Based on the EPR results and the thermalbehavior of Cu(II)-CR complexes, the scheme for the complexation of Cu(II) on the CRwas suggested.

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1. Introduction

The complex forming polymers possess chelating func-tional groups usually contain oxygen, nitrogen, sulphurand phosphorus donor atoms capable to coordinate withdifferent heavy and transition metal ions and to form me-tal-polymer complexes [1,2]. These materials frequentlyshow selectivity to certain metal ions, facilitating theiruse in preconcentration and separation of trace metal ionsat an appropriate pH range [3,4]. Solid phase extraction isan attractive technique, based on the use of a sorbent thatretains analytes, the selectivity being increased using li-gands that can coordinate or chelate the target metal ions[3]. Complex forming polymers are either synthetic [1–15]or generated from renewable resources [16–21]. Compara-tive with other biopolymers, chitosan is very reactive dueto the presence of amine groups which confer unique com-plexation properties of metal ions at a nearly neutral pH by

chelation, the sorption efficiency decreasing by amine pro-tonation [16,18–22].

Among the numerous polymeric ligands, those having across-linked matrix are the most used because they can beeasily regenerated and reused [2,11–16,19,20]. The slowerkinetics compared with soluble ligands are improved byincreasing the porosity or decreasing the bead size orcross-linking. Incorporation of metal ions in polymers notonly affects their physical characteristics like thermal sta-bility, crystallinity, and strength, but also their chemicalactivity. Therefore, the high interest in the polymer-metalcomplexes is motivated by their catalytic activity in hydro-genation [2], oxidation [1,2,5,11–15,17], and polymeriza-tion [2,5,23,24], antimicrobial and bactericide properties[7,9,10], paramagnetism, etc. Ligand exchange reactionsof polymer-metal complexes are used for selective removalof trace contaminants from water [25–27].

Our previous studies on the chelating resins (CR) werefocused on the preparation of some novel CRs bearing imino-diacetate (IDA) groups [28] and on the investigation of theirability to bind different heavy metals such as Cu(II), Co(II),

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* Corresponding author. Tel.: +40 232 217454; fax: +40 232 211299.E-mail address: sdragan@icmpp.ro (E.S. Dragan).

European Polymer Journal 45 (2009) 2119–2130

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Ni(II) [29], Pb(II), Cd(II), and Zn(II) [30]. The objectives ofthe present paper were: to prepare some novel metal-polymer complexes between Cu(II), Co(II) and Ni(II) ionsand CR bearing IDA ligand, which unlike the commercialresins has a higher mobility, caused by the presence ofa longer spacer between the matrix and IDA group, andto evaluate the influence of the counterion in the metalsalts and of the nominal cross-linking degree of CR onthe properties of the metal-CR complexes. FT-IR spectros-copy, thermogravimetric analysis (TGA), X-ray diffraction(XRD), and electron paramagnetic resonance (EPR) werethe methods used to characterize the CR-metalcomplexes.

2. Experimental

2.1. Materials

Divinylbenzene (DVB), technical grade (64% o-DVB,m-DVB, p-DVB and 36% ethylstyrene, by gas chromatogra-phy), purchased from Purolite (Victoria, Romania), wasdistilled at 400 Pa, at a temperature of 50 �C, before use.Benzoyl peroxide purchased from Fluka, was employedafter two times recrystallization from methanol. Acryloni-trile (AN), purchased from Sigma-Aldrich, was distilled at76–77 �C, 101.3 � 103 Pa. 1,2-Diaminoethane (EDA), pur-chased from Sigma-Aldrich, was distilled before use at118 �C. Sodium monochloroacetate (NaMCA) was obtainedby the neutralization reaction between the monochloro-acetic acid and NaOH, both purchased from Sigma-Aldrich,in ethanol.

The chelating resins (CR) with IDA groups employed inthis study as support for metal ions were synthesizedaccording to the procedure previously presented [29]. Inbrief, CR bearing IDA groups derived from AN-DVB copoly-mers were prepared in two steps: first, anion exchangerswith primary amine groups were obtained by the aminol-

ysis–hydrolysis reaction of the nitrile groups with ethylenediamine, and second, the chelating resins with IDA ligandwere prepared by the reaction of the primary amine groupswith NaMCA [29]. The general structure of the resins ispresented in Scheme 1.

The morphological and functional characteristics andmaximum metal adsorption capacity of the CR are summa-rized in Table 1.

All CRs have been treated first with 1 M NaOH and afterthat with 1 M HCl before the metal ions adsorption. Themetal salts used were copper (II) sulphate pentahydrate,cobalt (II) chloride hexahydrate, copper (II) chloride dihy-drate, cobalt (II) sulphate heptahydrate, nickel (II) chloridehexahydrate and nickel (II) sulphate, all from Aldrich.

2.2. Methods

2.2.1. Synthesis of polymer-metal complexesThe polymer-metal complexes were prepared by the

complexation of metal ions on CR using a batch equilib-rium procedure. Thus, 0.5 g of dry CR was placed in a flaskand contacted with 50 mL of the aqueous solution of eachmetal ion: Cu(II), Co(II), Ni(II), at room temperature andpH = 5.5, contact duration being 24 h. For the characteriza-tion, the complexes were rinsed several times with dis-tilled water, dried in air at room temperature for 24 h,and at 40 �C under reduced pressure for 48 h.

2.2.2. Characterization methodsFT-IR spectra were recorded with a Bruker Vertex FT-IR

spectrometer, resolution 2 cm�1, in the range of 4000–400 cm�1 by KBr pellet technique. X-ray diffraction patternswere recorded on a Bruker AXS D8 Advance diffractometerwith scanning scope of 0–45� (2h), scanning speed of 1.2�/min, using Cu-Ka radiation. Thermogravimetric analysis(TGA) was performed under nitrogen flow (20 cm3 min�1)at heating rate 10 �C/min from 25 to 900 �C with a Mettler

CH2 CH CH2 CH CH2 CH

C

O

NH (CH2)2 NCH2COOH

CH2COOH

C2H5CH2 CH

( ( () ) )CH2

CN

CH( )

Scheme 1.

Table 1Morphological and functional characteristics of the chelating resins (CR) and their maximum adsorption capacity for M(II) ions.

Sample Nominal cross-linkingdegree (% DVB)

qapa (g/cm3) Ssp

b (m2/g) Csvc (meq/ml) Csg

d (meq/g) Maximum adsorption capacityat pH 5, mmol M(II)/g CR

Cu2+ Co2+ Ni2+

CR-10 10 1.1605 5.67 1.86 4.885 3.83 2.35 2.78CR-15 15 0.903 17.1 1.106 2.907 2.62 1.98 2.22

a Apparent density.b Specific surface area.c Cation exchange capacity per volume.d Cation exchange capacity per dry resin.

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Toledo model TGA/SDTA 851. The initial mass of the sampleswas 3–5 mg. Constant operating parameters were kept forall the samples in order to obtain comparable data.

The EPR spectra were recorded on a Bruker ESP 300 Espectrometer operating at X-band (9.1–9.9 GHz) and

equipped with the Bruker NMR gaussmeter ER 035 M andthe Hewlett-Packard microwave frequencycounter HP at 77 K. The spectra were analysed by computersimulation programme based on resonance fields calculatedaccording to method of Sakaguchi et al. [31].

CR-10/CuCl2

4000 3500 3000 2500 2000 1500 1000 500

709799

9029791064

12231293

13921448

15521640

1728

2241

29373068

3410

CR-10

576633

712801

912971

106812061297

13801449

14901621

1727

2241

2930

3433

CR-10/CoCl2

577668712

801906

9701068

12041297

13851450

14891612

1727

2241

2932

3430

CR-10/NiCl2

577670712

800903

9761069

12031298

13851450

14891617

1727

2241

2930

3430

Wavenumber, cm-1

Fig. 1. FT-IR spectra of the CR-10/MCl2 complexes and of the chelating resin CR-10.

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3. Results and discussion

3.1. FT-IR

It is known that the metal complexation to a certainpolymeric ligand causes changes in the absorption spectraof the starting polymer [1,4–6,8–10]. FT-IR spectroscopyhas been used for the characterization of polymer-metalcomplexes, because the frequency at which a characteristicgroup of a polymer absorbs is modified by complexationwith metal ions, the shift or absence of a certain band pres-

ent in the starting ligand as well as the presence of newbands being observed. Therefore, the first informationabout the structural changes caused by the complexationof CRs with Cu(II), Co(II) and Ni(II) and on the coordinationmode of metal ions to the IDA bearing CRs were given byFT-IR spectra (Figs. 1–3).

The spectrum of CR-10 (Fig. 1) shows peaks at:2937 cm�1assigned to the stretching vibrations of CH, CH2

groups; 2241 cm�1assigned to the CN band from the resid-ual nitrile groups; 1728 cm�1 assigned to C@O in –COOH;1640 cm�1 assigned to the stretching vibrations of the

4000 3500 3000 2500 2000 1500 1000 500

3430

2933

2241

17271618

14891450

13811297

12031071

971911 801

712671 620576

CR-10/CuSO4

3429

2933

2241

17271616

14891450 1383

12971204

1069973

903801

712668

618577

CR-10/CoSO4

3427

2932

2241

17271614

14891450 1385

12971204

1069970

906801

712668

619576

CR-10/NiSO4

Wavenumber, cm-1

Fig. 2. FT-IR spectra of the CR-10/MSO4 complexes.

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C@O bond in amide group, known as amide I band;1552 cm�1 assigned to the deformation vibrations of theN–H bond, the amide II band, and to the –COO� groups;

1448 cm�1 assigned to the stretching vibrations of C@O in–COOH groups; 1392 cm�1 assigned to –COO� groups. Thebands at 1064 cm�1, 902 cm�1, 799 cm�1, 709 cm�1 are

4000 3500 3000 2500 2000 1500 1000 500

3426

30642934

2241

17231640

15561450

139312941248

1065982

905799

710

CR-15

3430

2934

2240

17271618

14891450

13841295

1206

1065972

912800

712633

567

CR-15/CuCl2

3422

2934

2240

17271620

14891450

13841295

1201 1067972

912800

712617

CR-15/CuSO4

Wavenumber, cm-1

Fig. 3. FT-IR spectra of the CR-15/CuCl2 and CR-15/CuSO4 complexes and of the CR-15.

Table 2Absorption bands in metal complexes of CR-10 compared with CR-10.

Sample/bond m band (cm�1)

CR-10 CR-10/CuCl2 CR-10/CoCl2 CR-10/NiCl2 CR-10/CuSO4 CR-10/CoSO4 CR-10/NiSO4

C@O, amide I 1640 1621 1617 1612 1618 1616 1614N–H bond, amide II, –COO� 1552 1490 1489 1489 1489 1489 1489–COO� 1392 1380 1385 1385 1381 1383 1385OC–N, amide III 1293 1297 1298 1297 1297 1297 1297C–N in IDA groups 1223 1206 1203 1204 1203 1204 1204

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assigned to the aromatic C–H out of plane bend [32]. Themain changes of the FT-IR spectra after complexation ofCR-10 with Cu(II), Co(II) and Ni(II) are summarized in Table2.

As Figs. 1 and 2 and Table 2 show, the bands at 1640 cm�1,1552 cm�1, 1392 cm�1, and 1223 cm�1shift to a lower fre-quency thus indicating the metal coordination throughIDA ligand. After complexation with Me(II), the bands at1552 cm�1, 1392 cm�1and 1223 cm�1 were red-shifted, ataround 1489 cm�1, 1383 cm�1 and 1204 cm�1, respectively.The band at 1293 cm�1, assigned to OC-N, amide III, weak inthe spectrum of CR-10, is strong in the metal/CR10complexes.

The bands characteristic to C@O in –COOH (1728 cm�1

and 1448 cm�1), which show that some carboxylic groupsremained nonionized at the metal adsorption pH, remainedalmost unchanged after the complexation (Figs. 1 and 2).Also, the absorption bands characteristic for the nitrilegroups (2241 cm�1), and the aromatic parts of the matrix

0 5 10 15 20 25 300

10

20

30

40

50

60

70

80

Inte

nsity

2 θ

CR-10 CR-10/CuCl2 CR-10/CoCl2

Fig. 4. XRD patterns of CR-10 and two metal complexes.

0

10

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600 700 800 900

T, oC

W%

1 2 3 7

-0.025

-0.02

-0.015

-0.01

-0.005

0

0 100 200 300 400 500 600 700 800 900T, oC

dm/d

T

1 2 3 7

(a)

(b)

Fig. 5. TG (a) and DTG (b) curves of the CR-10/M(II) complexes: CR10-CuCl2 (1), CR10-CoCl2 (2), CR10-NiCl2 (3) and CR-10 (7), at 10 �C/min.

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(1064 cm�1, 902 cm�1, 799 cm�1, 709 cm�1) were not influ-enced by the metal complexation. Coordination of metal ionto CR-10 was further supported by the new bands in 670–663 cm�1 region and 576 cm�1 assigned to M–O and M–Nstretching vibrations [33], respectively.

Fig. 3 collected the spectra of CR-15 and of the CR-15-Cu(II) complexes, with two sources of Cu(II), CuCl2 andCuSO4. The main deviations of the bands discussed abovefor the complexes formed on the CR-10 are visible also inthe spectra of CR-15-Cu(II) complexes, only the intensityof absorption was lower due to the higher nominal cross-linking degree.

3.2. X-ray diffraction study

The morphological information given by the X-ray dif-fraction studies have shown that the starting CR supportsand all CR-metal complexes were amorphous unlike thecrystalline nature of the metallic salts, since the effective

anchoring of metals to the chelating groups destroys theinherent order of metal in salts (Fig. 4).

From literature, it is known that even if the polymersupport is crystalline in nature, like chitosan, the higherthe metal adsorption was the lower the crystallinity degreeof the metal-chitosan complex [19]. On the other hand, themetal complexation on an amorphous polymer can lead topolymer-metal complexes with a high degree of crystallin-ity [1,5].

3.3. Thermal behavior

Thermal stability data of metal complexes are impor-tant to confirm the presence of metal ions, either as inclu-sion complexes or as adsorbed species. Metals ions presentas inclusion complexes are expected to have a greater ef-fect on the thermal properties of the chelating polymer[18]. It is known that the thermal stability of the poly-mer-metal complexes is strongly dependent on the struc-

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600 700 800 900

T, oC

W%

4 5 6 7

-0.025

-0.02

-0.015

-0.01

-0.005

0

0 100 200 300 400 500 600 700 800 900

T, oC

dm

/dT

4 5 6 7

(a)

(b)

Fig. 6. TG (a) and DTG (b) curves of the CR-10/M(II) complexes: CR10-CuSO4 (4), CR10-NiSO4 (5), CR10-CoSO4 (6) and CR-10 (7), at 10 �C/min.

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ture of the polymer ligand, and on the mode of complexa-tion, being higher [4,8,15] or lower [1,20] than that of thepolymer itself. Therefore, the thermal degradation behav-ior of metal-CR complexes was compared to the thermalbehavior of the chelating matrix, CR-10 and CR-15. Thethermogravimetric, TG, curves and the differential weightloss, DTG, curves, recorded in inert atmosphere, for CRsand CR-M(II) complexes are presented in Figs. 5–8. The ini-tial water loss stage below 100 �C has been ignored fromdiscussion.

The summary of the important thermogravimetric char-acteristics obtained from the thermograms are listed inTable 3.

As Figs. 5a–8a and Table 3 show, in all cases the pres-ence of metal ion decreased the thermal stability, indicat-ing that the interaction between the ligand group and themetal was rather intrachain than interpolymer chains, asother metal-polymer complexes showed [1,4,34]. Usingas thermal stability criteria the initial temperature ofdecomposition (Ti) for the samples decomposition, the

thermal stability series, irrespective of the counterion,was established as being the following:

Cu2þ < Co2þ < Ni2þ

The lowest thermal stability of the complexes with Cu(II) iscorrelated with the highest complexing ability of CRs forthis metal ion compared to the other two metals (Table1), but the highest thermal stability of Ni(II)-CR complexes,irrespective of the counterion, is not correlated with theamount of the metal, this being higher than that of Co(II).

The TGA results can be also evaluated from the DTGpeaks. DTG data show that the CR-10 has one minor peakat 304 �C and one major peak at 415 �C, and CR-15 has oneminor peak at 290 �C and one major peak at 433 �C (Fig. 7and Table 3). After metal complexation of CR-10 with Cu(II),the minor peak shifted at 238 �C, when CuCl2 was used forloading, and at 216 �C, when CuSO4 was the source of Cu(II).The shift of the minor peak was also important in the case ofCR-15 (from 290 �C to 215 �C, when CuCl2 was used for com-plexation), the major peak being less influenced by metal

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600 700 800 900T, oC

W%

7 1 4

-0.02500

-0.02000

-0.01500

-0.01000

-0.00500

0.00000

0 100 200 300 400 500 600 700 800 900T, oC

dm/d

T

7 1 4

(b)

(a)

Fig. 7. TG (a) and DTG (b) curves of the CR-10/M(II) complexes CR10-CuCl2 (1) and CR10-CuSO4 (4) compared to CR-10 (7), at 10 �C/min.

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complexation. Significant changes in the thermal degrada-tion happened in the case of Co(II)-CR-10 and Ni(II)-CR-10,only one major peak being observed for all metal-polymercomplexes. However, the DTG peak is shifted at a much low-er value when CoSO4 was the source of Co(II), i.e., 350 �C. Theshifts of the DTG peaks after metal complexation can beattributed to the metal complexation on CR as for other me-tal-polymer complexes [20].

3.4. EPR

EPR studies of copper(II) complexes formed with CRswere also used to explain the possible modes of coordina-tion of divalent transition metal cations by the CRs. In or-der to find out the possible modes of coordination of

divalent transition metal cations we decided to perform asorption of copper(II) and to analyse the obtained materialusing EPR method. The EPR spectra of the polymeric sam-ples fully loaded with Cu(II) ions exhibited typical broad-ening of the lines due to spin-spin interaction caused bytoo high content of Cu(II) ions. To improve the resolutionof the hyperfine structure we decided to remove partiallythe Cu(II) ions by washing the samples with sulphuric acidsolution. In the series 1 all samples were desorbed usingacid solution of pH 0.5 and washed with water until thepH reached 3.5. In the series 2 the washing solution wasless acidic (pH = 1.5) and rinsed with water until the pHreached 3.5.

All EPR spectra of samples from series 1 and series 2have signals, which can be ascribed to two types of com-

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600 700 800 900

T, oC

W%

9 8 10

-3.50E-02

-3.00E-02

-2.50E-02

-2.00E-02

-1.50E-02

-1.00E-02

-5.00E-03

0.00E+00

0 100 200 300 400 500 600 700 800 900T, oC

dm/d

T

9 8 10

(a)

(b)

Fig. 8. TG (a) and DTG (b) curves of the CR-15/Cu(II) complexes CR15-CuCl2 (8) and CR15-CuSO4 (10) compared to CR-15 (9), at 10 �C/min.

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plexes being in equilibrium: the complex I with higher va-lue of the parameter gII, and complex II with lower value ofthe gII parameter. Various intensity of the signals indicatesvarious proportions of the complexes at equilibrium. The

EPR spectra are typical for Cu(II) complexes of tetragonalgeometry with unpaired electron of dx2–y2 orbital type.

Fig. 9 presents the spectra of two complexes at equilib-rium (for sample 3, with 10% of DVB predominant complexI and for sample 2, with 15% of DVB predominant complexII). One can find also the differential spectra: of complex I(by subtracting spectrum of sample 3 series 1 from almostpure spectrum of sample 3 series 2) – this is spectrum 3K–3L and of complex II – this is spectrum 2L–2K.

Simulation of the experimental spectra of complexes Iand II gave the calculated spectrum I sim (upper part ofFig. 9) and spectrum II sim (lower part of Fig. 9). Spectralparameters for complex I are gII = 2.303, g\ = 2.065,AII = 156 G, and for complex II are gII = 2.266, g\ = 2.06,AII = 173 G. According to the systematic analysis of theEPR spectra of the model complexes of Cu(II) and mono-meric iminodiacetate ligands (IMDI) and spectra of ion-exchangers having iminomonocarboxylic ligands type Icomplex (gII = 2.303, AII = 156 G) and type II complex II(gII = 2.271 AII = 166-174 G) corresponds to the coordina-tion with three donor atoms –N2O, originating from oneligand [35–37]. Much higher values of AII and lower gII seenfor complex II indicates the presence of two nitrogendonors in the xy plane of tetragonal Cu(II) complex. Thishas been proved by the introduction of NH3 to the resin

Table 3Thermogravimetric characteristics of CRs and their metal complexes.

Sample Weight loss (%) DTG peaks (Ma, major; Mi, minor)

Stage 1 Stage 2 Stage 3

CR-10 279–389 389–439 >439 304 Mi 415 Ma13.43 19.02 28.72

CR10-CuCl2 192–368 368–444 >444 238 Mi 431 Ma17.00 33.21 29.64

CR10-CoCl2 240–453 >453 – – 428 Ma60.89 14.92

CR10-NiCl2 277–435 >626 – – 420 Ma50.51 17.93

CR10-CuSO4 191–397 397–449 – 216 Mi 426 Ma11.56 44.65

CR10-CoSO4 266–900 – – – 350 Ma74.42

CR10-NiSO4 279–438 >438 – – 430 Ma56.11 14.31

CR-15 265–395 395–449 – 290 Mi 433 Ma17.93 54.35

CR15-CuCl2 193–316 316–451 – 215 Mi 439 Ma13.49 57.56

CR15-CuSO4 195–366 366–446 – 219 Mi 426 Ma13.49 55.33

The significance of bold values shows the weight loss.

2L

2L-2K

Magnetic field [G]

3K

3K-3l

2600 2800 3000 3200 3400 3600

sim

sim

Fig. 9. The EPR spectra of the investigated resins loaded with Cu(II).

CH2

CN

CH( ) )()(( )

-

-

H

HO+2M

O

O

O

O

C

C

CH2 CH CH2 CH CH2 CH

C

O

NH (CH2)2 N

C2H5CH2 CH

Scheme 2.

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phase and thus forcing the coordination of ammonia in-stead of one of nitrogens from the resin. The spectra ofcomplex II have the same EPR parameters both with andwithout the presence of ammonia.

Based on the EPR results and the thermal behavior ofCu(II)-CR complexes, Scheme 2 for the complexation ofCu(II) on the CR was suggested.

4. Conclusions

The IDA ligand bearing chelating resins, CR-10 and CR-15,loaded with copper(II), cobalt(II) and nickel(II)ions, by usingboth chloride and sulphate salts, were characterized usingdifferent techniques. The FT-IR spectroscopy confirmed theformation of the complexes between the CR-10 and CR-15and the metal cations. Thus, after complexation with Me(II),the bands at 1552 cm�1, 1392 cm�1and 1223 cm�1 werered-shifted, at around 1489 cm�1, 1383 cm�1 and 1204cm�1, respectively. The metal complexation on CRs was alsosupported by both TGA as well as DTG results. TGA analysisdata showed lower thermal stability for Cu(II), Co(II) andNi(II)-CR complexes than for the ligand resins. The presentstudy on the properties of a series of metal complexes ofthe novel IDA resins shows that the decrease in the observedthermal stability is intimately related to the type of CR-M(II)complex. It was also observed that the nature of counterionhad a contribution on the properties of a certain CR-M(II)complex.

According to the systematic analysis of the EPR spectraof the model complexes of Cu(II) and monomeric iminodi-acetate ligands (IMDI) and spectra of CR having IDAligands, type I complex (gII = 2.303, AII = 156 G) and typeII complex (gII = 2.271 AII = 166–174 G) corresponds tothe coordination with three donor atoms –N2O, originatingfrom one ligand.

Acknowledgement

EPR spectra were obtained and analysed at the Univer-sity of Wrocław by Prof. Julia Jezierska.

References

[1] Kaliyappan T, Swaminathan CS, Kannan P. Studies on poly(2-hydroxy-4-metacryloyloxybenzophenone)-metal complexes. EurPolym J 1997;33(1):59–65.

[2] Kaliyappan T, Kannan P. Co-ordination polymers. Prog Polym Sci2000;25(3):343–70.

[3] Beauvais RA, Alexandratos SD. Polymer-supported reagents for theselective complexation of metal ions: an overview. React FunctPolym 1998;36(2):113–23.

[4] Tuncel M, Özbülbül A, Serin S. Synthesis and characterization ofthermally stable Schiff base polymers and their copper(II), cobalt(II)and nickel(II) complexes. React Funct Polym 2008;68(1):292–306.

[5] Nanjundan S, Jone Selvamalar CS, Jayakumar R. Synthesis andcharacterization of poly(3-acetyl-4-hydroxyphenyl acrylate) and itsCu(II) and Ni(II) complexes. Eur Polym J 2004;40(10):2313–21.

[6] Diaz E, Valenciano RB, Katime IA. Study of complexes of poly(vinylpyrrolidone) with copper and cobalt in solid state. J Appl Polym Sci2004;93(4):1512–8.

[7] Soykan C, Coskun R, Kirbag S. Poly(crotonic acid-co-2-acrylamido-2-methyl-1-propanesulfonic acid)-metal complexes with cooper (II),cobalt(II), and nickel(II): synthesis, characterization andantimicrobial activity. Eur Polym J 2007;43(9):4028–36.

[8] Marambio OG, Pizarro GC, Jeria-Orell M, Huerta M, Olea-Azar C,Habicher WD. Poly(N-phenylmaleimide-co-acrylic acid)-copper(II)

and poly(N-phenylmaleimide-co-acrylic acid)-cobalt(II) complexes:synthesis, characterization, and thermal behavior. J Polym Sci Part APolym Chem 2005;43(20):4933–41.

[9] Parveen S, Ahamad T, Nishat N. New anti-bacterial polychelates:synthesis, characterization, and anti-bacterial activities ofthiosemicarbazide-formaldehyde resin and its polymer-metalcomplexes. Appl Organometal Chem 2008;22(2):70–7.

[10] Nishat N, Ahamad T, Zulfequar M, Hasnain S. New antimicrobialpolyurea: synthesis, characterization, and anti-bacterial activities ofpolyurea-containing thiosemicarbazide-metal complexes. J ApplPolym Sci 2008;110(6):3305–12.

[11] Jakubiak A, Owsik IA, Kolarz BN. The oxidation of hydrochinonecatalysed by Cu(II) ions immobilized on acrylic resins. The influenceof ionic liquid. React Funct Polym 2005;65(1–2):161–7.

[12] Kolarz BN, Jakubiak A, Jezierska J, Dach B. Polymeric supports withamino groups from halogenoacetylated styrene/divinylbenzenecopolymers. React Funct Polym 2008;68(8):1207–17.

[13] Maurya MR, Sikarwar S, Joseph T, Manikandan P, Hlligudi SB.Synthesis, characterization and catalytic potentials of polymeranchored copper(II), oxovanadium(IV) and dioxomolybdenum(VI)complexes of 2-(a-hydroxymethyl)benzimidazole. React FunctPolym 2005;65(1–2):71–83.

[14] Gupta KC, Sutar AK. Catalytic activities of polymer-supported metalcomplexes in oxidation of phenol and epoxidation of cyclohexene.Polym Adv Technol 2008;19(3):186–200.

[15] Gupta KC, Sutar AK. Catalytic activity of polymer anchored N,N0-bis(O-hydroxy acetophenone) ethylene diamine Schiff base complexesof Fe(III), Cu(II) and Zn(II) ions in oxidation of phenol. React FunctPolym 2008;68(1):12–26.

[16] Ruiz M, Sastre AM, Guibal E. Palladium sorption on glutaraldehyde-crosslinked chitosan. React Funct Polym 2000;45(3):155–73.

[17] Guibal E, Vincent T, Touraud E, Colombo S, Ferguson A. Oxidation ofhydrochinone to p-benzochinone catalyzed by Cu(II) supported onchitosan flakes. J Appl Polym Sci 2006;100(4):3034–43.

[18] S�enöz H, Güner A, Tunoglu N. Synthesis of dextran dicarboxylic acidand investigation of its complexes with metal ions in aqueoussolutions. J Appl Polym Sci 2004;93(5):2262–5.

[19] Trimukhe KD, Varma AJ. A morphological study of heavy metalcomplexes of chitosan and crosslinked chitosan by SEM and WAXRD.Carbohydr Polym 2008;71(4):698–702.

[20] Trimukhe KD, Varma AJ. Metal complexes of crosslinked chitosans:correlations between metal ion complexation values and thermalproperties. Carbohydr Polym 2009;75(1):63–70.

[21] Wan Ngah WS, Endud CS, Mayanar R. Removal of cooper(II) ionsfrom aqueous solution onto chitosan and cross-linked chitosanbeads. React Funct Polym 2002;50(2):181–90.

[22] Enescu D, Hamciuc V, Timpu D, Harabagiu V, Simionescu BC.Polydimethylsiloxane-modified chitosan. Complexes of divalentmetals. J Optoelectron Adv Mater 2008;10(6):1473–7.

[23] Kaliyappan T, Kannan P. Synthesis, spectral and thermal properties ofpoly(2-hydroxy-4-methacryloyloxybenzaldehyde)-metal complexes.J Polym Sci Part A Polym Chem 1996;34(17):3551–7.

[24] Zeng X, Zhang Y, Shen Z. Ring-opening polymerization ofpropylene oxide by chitosan-supported rare earth catalyticsystem and its kinetics. J Polym Sci Part A Polym Chem 1997;35(11):2177–82.

[25] Helfferich FG. Ion exchange. New York: McGraw-Hill BookCompany; 1962. p. 222.

[26] Zhao D, SenGupta AK. Ligand separation with a copper(II)-loadedpolymeric ligand. Ind Eng Chem Res 2000;39(2):455–62.

[27] Henry WD, Zhao D, SenGupta AK, Lange C. Preparation andcharacterization of a new class of polymeric ligand exchangers forselective removal of trace contaminants from water. React FunctPolym 2004;60(1):109–20.

[28] Dragan ES, Avram E, Dinu MV. Organic ion exchangers as beads.Synthesis, characterization and applications. Polym Adv Technol2006;17(7–8):571–8.

[29] Dinu MV, Dragan ES. Heavy metals adsorption on someiminodiacetate chelating resins as a function of the adsorptionparameters. React Funct Polym 2008;68(9):1346–54.

[30] Dinu MV, Dragan ES, Trochimczuk AT. Sorption of Pb(II), Cd(II) andZn(II) by iminodiacetate chelating resins in non-competitive andcompetitive conditions. Desalination, accepted for publication.

[31] Sakaguchi U, Arata Y, Fujiwara S. Angular variation of theortorhombic ESR spectra of Cu(II). J Magn Res 1973;9(1):118–20.

[32] Coates J. Interpretation of infrared spectra. A practical approach. In:Meyers RA, editor. Encyclopedia of analytical chemistry. Chichester,UK: John Wiley & Sons Ltd.; 2000. p. 1–23.

E.S. Dragan et al. / European Polymer Journal 45 (2009) 2119–2130 2129

Author's personal copy

[33] Mohamed GG. Structural chemistry of some new azo complexes.Spectrochim Acta Part A 2001;57(3):411–7.

[34] Choi SJ, Geckeler KE. Synthesis and properties of hydrophilicpolymers. Part 8. Preparation, characterization and metalcomplexing of poly[(2-hydroxyethyl)-DL-aspartamide] in aqueoussolution. Polym Int 2000;49(11):1519–24.

[35] Vishnevskaya GP, Molochnikov LS. Safin RSh. EPR in ionexchangers. Moscow: Nauka; 1992.

[36] Jezierska J, Trochimczuk AT, Kedzierska J. Coordinatingproperties of polymers with N-substituted diamides ofmalonic acid towards Cu(II); EPR studies. Polymer1999;40(12):3611–6.

[37] Trochimczuk AT, Jezierska J. New amphoteric chelating/ionexchange resins with substituted carbamylethylenephosphonates;synthesis and EPR studies of their Cu(II) complexes. Polymer2000;41(9):3463–70.

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