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Synthesis and characterization of some mixed ligands complexes from o-phthalic acid as primary ligand.


In the past decade the interest of transition metal complexes is shifted from using inorganic anions to organic anions and large number of complexes of organic anions such as phthalimide, succinimide, oxalate, formate, benzoate and phthalate with first transition metals series have been reported [1,2].

Modes of metal ion coordination by bidentate were extensively investigated by many workers and (N, N), (O, O) bidentate chelate through the [N.sup.2], [O.sup.2] and [N.sup.4], [O.sup.4] atoms were established to be the most acceptable mode of coordination [3,4] The chemistry of these complexes has interested many workers due to their important role in biological, bacterial, DNA-Binding properties and other uses [5,6].

The crystal structure of [[[{[Ph.sub.3]P).sub.2][Cu.sub.2][([mu],-Cl).sub.2]([mu],-pyrazine)}.sub.[infinity]]] reveals acentro symmetric dimer in the solid state. The dimer has an inversion center between the two coppers and in the center of the bridging pyrazine ligand that links the chloride-bridged copper pairs in an infinite chain. The geometry around each copper is a distorted tetrahedral [7].

Kinetics and mechanism of substitution in trans-dichloro bis (ethylenediamine) cobalt(III) chloride by organic amines including phe-nylethylamine in MeOH-DMF solution also was studied [8].

Nickel(II) complexes based on combination of N-N ligands with 6,7-dimethoxy-1,2,3,4-tetrahydro isoquinoline or 3,4-dimethoxy pheneth-ylamine of the formulas [Ni(phen)(6,7,THIQ) [([H.sub.2]O).sub.2]Cl], [Ni(bpy) (6,7-TH IQ) [([H.sub.2]O).sub.2]Cl], [Ni(en)(6,7-THIQ) [([H.sub.2]O).sub.2]Cl], [Ni(phen)[(3,4-PHA).sub.2] ([H.sub.2]O)Cl] and [Ni(bpy)[(3,4-PHA).sub.2].([H.sub.2]O)Cl] was obtained and they suggest deformed octahedral arrangement about nickel center with one chloride coordinated to nickel and the other one is situated out of coordination sphere [9].

The present paper report the preparation and characterization of some new complexes formed by the reaction of metal phthalate as primary complex and their reaction to form adducts with some amines.


All chemicals used were of high purity (BDH or Fluka). The metal content was estimated spectrophotometrically using Shimadzu Atomic Absorption 670 spectrophotometer. Melting point were determined using Buchi 510 melting point apparatus. Infrared spectra were recorded using Perkin-Elmer 580B spectrophotometer in the range 4000-200[cm.sup.-1] as KBr pellets. The electronic spectra were recorded on Shimadzu UV-visible spectrophotometer UV-160 for [10.sup.-3] M solution of the complexes in DMSO at 25C[degrees] using 1cm quartz. Conductivity measurements were carried out on [10.sup.-3] M solution of the complexes in DMSO using (PMC3 (Jenway) conductivity model) at room temperature. Magnetic measurements were carried out on the solids by the Faradys method using Bruker BM6 instrument and AA670 for the determination of metal content.

Preparation of Compounds

Starting materials

The compounds Co[Cl.sub.2] x 6[H.sub.2]O, Ni[Cl.sub.2] x 6[H.sub.2]O, Cu[Cl.sub.2] x 2[H.sub.2]O, ethylene diamine, benzyl methyl amine, phthalic acid and sodium bicarbonate were commercial products and used without further purification.

Preparation of Complexes. [Na.sub.2][M[(L).sub.2]]

The primary complex, metal phthalate was prepared by mixing of suspension of phthalic acid (1.66g-0.01mole) in water with sodium bicarbonate to obtain neutral solution. The sodium phthalate (3.76g-0.02mole) so obtained was reacted with metal salts Co[Cl.sub.2].6[H.sub.2]O, Ni[Cl.sub.2].6[H.sub.2]O and Cu[Cl.sub.2].2[H.sub.2]O (2.38g-0.01mmole, 2.38g-0.01mole, 1.70g-0.01mole) respectively, dissolved in ethanol. The precipitation of metal phthalate was filtered off, washed with ethanol and dried.

Preparation of the adducts [Na.sub.2][M[(L).sub.2](L)], [Na.sub.2][M[(L).sub.2][(L').sub.2]] L' = en, BMA

The mixed ligand complexes were prepared by the addition of an excess of the secondary ligands (0.6g-0.01mole) ethylene diamine dissolved in ethanol to cobalt phthalate, nickel phthalate and Copper phthalate (3.86g-0.01mole), (3.87g-0.01mol) and (3.91g-0.01mol) respectively, suspended in ethanol. The mixture was then refluxed for about two hours until the reaction was completed, which was indicated by color change or dissolve of the original solid. After cooling, the separated compounds were filtered off, washed with cold ethanol and dried. Similar procedure used for the preparation of benzyl methyl amine (BMA) adducts.

Theoretical Calculations

The molecular mechanic techniques were applied to compute the steric energy, optimized geometry, and physical properties of each complex using MM2 module in the CS ChemOffice 9.0 molecular modeling program package. These were performed using computer Pentium(R) D 3.40 GHz 2.4 GHz.

Results and Discussion

The physical properties of the solid complexes of cobalt(II), nickel(II) and copper(II) with phthalate ion and their adducts with (en) and (BMA) are presented in Table 1. The complexes are quite stable in dry air, very slowly affected by moisture and fair stable to heat as they melt (decompose) at 300-345C[degrees]. They are insoluble in most organic solvent expect for DMF or DMSO. The elemental analysis (Table 2) of these complexes assigned to 1:2 molar ratio of [M.sup.2+]: phthalate Ligand and 1:1 molar ratio of M[(L).sub.2]: en ligand or 1:2 of M[(L).sub.2]: BMA ligand.

The most important IR assignment of the ligand as well as their bonding sites (Table 3) have been determined by a careful comparison of the spectra of the ligand with those of their complexes. The IR spectra of the phthalate ion showed medium band at 1700 [cm.sup.-1], 1450 [cm.sup.-1] assigned to [??] (C = O) and [??] (C - O) vibration respectively was found to decrease upon complexation. This indicates that this group had been involved in the coordination with metal ion through oxygen atoms [10,11].

Further, the IR spectra of the complexes show a medium band around 427-461 [cm.sup.-1] which assigned to [??] M - N indicating that the metal ion coordinated through nitrogen atom [12]. Furthermore the [??] M - O band is observed at 410-502 [cm.sup.-1] indicating the coordination occurs from oxygen atom [10].

Magnetic properties

The magnetic moment data of complexes under investigation are calculated from the corrected magnetic susceptibilities which determined at room temperature (Table 1). The [[mu].sub.eff] values reported for the complexes are slightly higher than spin-free value of respective metal ions indicating tetrahedral geometry for the complexes 1-3 [13] as well as an octahedral geometry for the complexes 4-9 [9,14].

Electronic spectra

The electronic spectra of Co(II) complex No.1 recorded in solution show bands at 11320 [cm.sup.-1] and 13332 [cm.sup.-1] due to [sup.4][A.sub.2](F) [right arrow] [sup.4][T.sub.1](P) ([[??].sub.3]) transition in tetrahedral symmetry while ([[??].sub.1]), ([[??].sub.2]) was not observed due to instrumental limit [15]. While the cobalt complexes 4 and 7 show three bands at 10488-12978, 13107-15331, and 26210-28826 [cm.sup.-1] which may attributed to transitions of [sup.4][T.sub.1]g (F) [right arrow] [sup.4][T.sub.1]g (F) ([[??].sub.1]), 4[sup.4][T.sub.1]g (F) [right arrow] [sup.4][A.sub.2]g (F) ([[??].sub.2]) and [sup.4][T.sub.1]g (F) [right arrow] [sup.4][T.sub.1]g (P) ([[??].sub.3]) respectively. These values suggest octahedral geometry for these complexes [9,16].

The electronic spectra of Ni complex No. 2 the observed bands 12261[cm.sup.-1] and 15202[cm.sup.-1] are attributed to the transition [sup.3][T.sub.1] (F) [right arrow] [sup.3][T.sub.1] (P) ([[??].sub.3]) in tetrahedral geometry while ([[??].sub.1]), ([[??].sub.2]) was not observed due to instrumental limit [15]. Where as the Ni(II) complexes 5 and 8 show the presence of three d-d transition bands at 10535-12541, 13146-15216, and 27023-27478 [cm.sup.-1] regions assigned to the transitions [sup.2][A.sub.2]g(F)[right arrow] [sup.3][T.sub.2]g(F)a([[??].sub.1]), [sup.3][A.sub.2]g(F)[right arrow] [sup.3][T.sub.2]g(F)a([[??].sub.2])a and [sup.3][A.sub.2]g (F) [right arrow] [sup.3][T.sub.1]g (F) ([[??].sub.3]) respectively. This is consistent with the octahedral geometry of the complexes [9,16].

In the electronic spectra of the Cu(II) complex No. 3 the observed bands at 12982 [cm.sup.-1] and 15731 [cm.sup.-1] which are correspond to the transition [sup.2][T.sub.2] - [E.sub.2] and other transition at 30385 [cm.sup.-1] which correspond to charge transfer which consistent with tetrahedral geometry [17].

Three shoulder bands appear in the Cu(II) complexes 6 and 9 at 10541-13212, 15064-15337 and 27082-28619 [cm.sup.-1] which may be assigned to [sup.2][B.sub.1]g [right arrow] [sup.2][A.sub.1]g, [sup.2][B.sub.1]g [right arrow] [sup.2][B.sub.2]g and [sup.2][B.sub.1]g [right arrow] [sup.2]Eg transition respectively. The [E.sub.g] ground state is highly susceptible to Jan-teller configuration stability due to which Cu(II) ion in the complexes shows distorted octahedral geometry [16].

The molar conductivities of [10.sup.-3] M solution of the complexes indicate that all complexes are 1:2 electrolytes in DMSO (Table1) [18].

Theoretical calculations are useful to deduce and characterize the optimized geometry of the prepared compounds and to emphasize the physical measurements. The optimized geometry of each complex and ligands were obtained by computing the minimum steric energy using MM2 CS ChemOffice version 9.0 molecular modeling program. The steric energies for the prepared compounds are listed in Table 4. The calculated optimized geometries and steric energies for the complexes 1-3 indicate that there is a square planar environment around the central metal ion but complexes 4-9 adopted octahedral geometry around the central metal ion [19-21]. The configuration of complex (1) (Fig.2) was drawn here, as an example, with some selected bond lengths and angles (Table 5).

According to the above measurements, we suggest the following structures of the complexes and adducts as in Fig. 1.




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Eid A. Abdal-razaq (a), Omar M. Al-ramadane (b) and Khansa S. Al-numa (b)

(a) Department of Chemistry, College of Science, Al-Hussein Bin Talal University, Ma'an, Jordan

(b) Department of Chemistry, College of Science, University of Mosul, Iraq
Table 1: Physical Properties and Complexes Electrical Conductivities
of the Complexes. * Decomposition

Seq. Compounds Color m.p.

1 [Na.sub.2][[([C.sub.8] Violate 194
2 [Na.sub.2][[([C.sub.8] Green 186
3 [Na.sub.2][[([C.sub.8] Brown 193
4 [Na.sub.2][[([C.sub.8] Dark blue 291
5 [Na.sub.2][[([C.sub.8] Dark brown 306
6 [Na.sub.2][[([C.sub.8] Dark brown 312 *
7 [Na.sub.2][[([C.sub.8] Dark brown 310
8 [Na.sub.2][[([C.sub.8] Dark green 345 *
9 [Na.sub.2][[([C.sub.8] Dark brown 321

Seq. Cond. [LAMBDA] [[mu].sub.eff]
 [ohm.sup.-1] x
 [cm.sup.2] x

1 73.6 4.12

2 79.3 3.94

3 81.2 2.15

4 76.4 4.80

5 70.5 3.26

6 80.0 1.42

7 69.8 4.73

8 78.7 3.53

9 72.9 1.83

Table 2: The Elemental Analysis of the Prepared Complexes.

Complexes Yield% Elemental analysis: Found

 %M %C

1 64 13.56 (13.84) 43.89 (44.35)
2 66 13.28 (13.56) 44.01 (44.37)
3 80 14.15 (14.51) 43.92 (43.88)
4 75 11.48 (11.95) 43.10 (43.82)
5 80 11.66 (11.91) 43.76 (43.84)
6 69 12.31 (12.76) 44.10 (43.41)
7 72 8.33 (8.75) 56.79 (56.89)
8 71 8.20 (8.72) 57.04 (56.91)
9 65 9.07 (9.37) 56.62 (56.51)

Complexes Elemental analysis: Found

 %H %N

1 1.87 (1.85) -
2 1.91 (1.85) -
3 1.79 (1.83) -
4 3.22 (3.25) 5.70 (5.68)
5 3.28 (3.25) 5.74 (5.68)
6 3.18 (3.22) 5.97 (5.63)
7 4.38 (4.44) 4.08 (4.15)
8 4.52 (4.45) 4.20 (4.15)
9 4.39 (4.41) 4.17 (4.12)

Table 3: IR Spectra (cm-1) and Electronic Spectra of
the Phthalate Ion and Complexes.

Compounds [??] (C=O) [??] (C-O) [??] (M-O)

[C.sub.8] 1700(s) 1450(m) -
1 1605(m) 1402(w) 412(s)
2 1582(m) 1421(m) 460(s)
3 1561(w) 1400(s) 410(w)
4 1612(s) 1406(s) 455(s)
5 1548(s) 1401(w) 502(m)
6 1576(w) 1418(w) 483(m)
7 1601(m) 1404(w) 491(m)
8 1593(m) 1408(m) 470(m)
9 1588(m) 1410(w) 433(m)

Compounds [??] (M-N) [[lambda].sub.max] (UV).

[C.sub.8] - -
1 - 11320, 13332
2 - 12261, 15202
3 - 12982, 15731, 30385
4 427(m) 11545, 12978, 15331, 28826
5 432(m) 12541, 13146, 27023
6 452(m) 13212, 15337, 28619
7 437(w) 10488, 13107, 14662, 26210
8 429(m) 10535, 12091, 15216, 27478
9 461(m) 10541, 15064, 27082

Table 4: Computational Steric Energies of the Prepared

complexes Steric energy

Ligand 7.485
1 129.006
2 80.856
3 59.848
4 122.155
5 95.255
6 55.683
7 98.595
8 82.842
9 57.303

Table 5: Some Selected parameters of the
Complex (2), [Na.sub.2][[([C.sub.8]

 Selected Value

Bond Angles O1-Ni-O2 105.62
 ([degrees]) O3-Ni-O4 107.10
 O3-Ni-O1 112.36
 O4-Ni-O2 111.32
 O3-Ni-O2 112.22
 O4-Ni-O1 107.50
Bond lengths O1-Ni 1.747
 (A[degrees]) O2-Ni 1.747
 O3-Ni 1.742
 O4-Ni 1.745
 C3-O3 1.366
 C3-O7 1.227
 C4-O4 1.364
 C4-O8 1.226
 C1-O1 1.368
 C1-O5 1.226
 C2-O2 1.367
 C2-O6 1.229
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Author:Abdal-razaq, Eid A.; Al-ramadane, Omar M.; Al-numa, Khansa S.
Publication:International Journal of Applied Chemistry
Date:Jan 1, 2011
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