Synthesis,  Characterization  and Study of Chemo-Physical  Properties  of New Ligands  with  Complexes of (Zn2+)

 

ThanaaAbdAlameerHelal1, AlaaAbadiHabeab2

1Chem. Dept., College of Education, Kufa University, Iraq

2Dept. of Pharmaceutical Chemistry, College of Pharmacy, University of Kufa., Iraq.

*Corresponding Author E-mail:

 

ABSTRACT:

This study involved, synthesis of new three ligands from macro compound which contain aldamine  or ketamine groups  linked  with  azo groups  in  same  molecule.   macro ligands were synthesized by reacting of various diketone compounds such as (malonic acid, benzaldehyde derivatives ..) with  hydrazine compounds  or  methylene di amine  or azo compounds via condensation reaction  or azotation reaction and coupling reaction to produce  three ligands [(HIP), (HAT), (HIM)] of macro ligands and their complexes with zinc ion (II).

The synthesized compounds were confirmed by (I.R ,UV –Vis, H.NMR,  Atomic Absorption ,(C.H.N) –analysis), molar conductance and melting points.

 

KEYWORDS: hydrazimine,  complex of Zn,  4-coordination, diketon ligand, transition metals.

 

INTRODUCTION:

Macro ligands have a long history of application in analytical and inorganic chemistry, were clinically known and have a wide range of bio activities such as antibacterial drugs(1,2),in synthesis of polymers(3,4), heterocyclic compounds (5,6) have applications in several fields(7-10) which due to several methods for preparing imine compounds in literature , but the method which is carried out through condensation reaction of carbonyl compounds with primary aromatic amine is most used are chelating ligands in coordination chemistry ,they are also useful in catalysis and in medicine , the utility of Schiff bases lay in their usefulness as synthons in the synthesis of bioactive molecules, Schiff bases belongs to a widely used group of organic intermediates important for production compounds as a ligand with transition metals to form complexes(11-13) and in synthesis of several polymers.

 

These compounds included Schiff basses and azo groups– bi molecular at same time or some of them included  two Azo- groups or two  Schiff bases(9-13) which give it ability to act as multi dentate ligands for transition metal ions , most of these compounds used are chelating ligands in coordination chemistry.

 

EXPERIMENTAL:

Melting points were determined in open capillary tube and were uncorrected. The I.R. -spectra were recorder in KBr–disc, Shimadzu (8300)., (C.H.N) – elemental analysis, Atomic absorption., UV–Vis–spectraphotometer., H.NMR-spectra., molar conductance (DMSO –solvent), mole ratio of complexes, other physical properties.

 

Synthesis  of  ligand (HIP) :

1,3 –{(2-hydroxy phenyl) –(hydrazamine)}-propandion.

This compound was synthesized according procedures(5,10), malonicacide (0.01mole) and (0.02mole) from hydrazine were refluxed in presence of absolute ethanol with drops of sulphuric acid for (2hrs), the precipitate was filtered and dried, which (0.01 mole) reacted with (0.02 mole) of salicyldehyde with reflux for (3hrs) in presence of absolute ethanol with drops of glacial acetic acid, then re crystallized with absolute ethanol to yield 82% of ligand (HIP).

 

Synthesis  of  ligand (HAT) :

2,6- bis(1,3-dihydroxy phenyl azo )- 4-nitro toluine

(0.02mole) of 1,3-dihydroxy  aniline was dissolved in (3ml) of hydro chloric acid and (0.8gm) of sodium nitrite in temperature (0-5)̊ C then ethanolic solution of 4-nitro toluine (0.01mole) added , after (48hrs) , the precipitate was filtered and dried, to yield (89%)from ligand (HAT).

 

Synthesis of ligand (HIM) :

4-(methyl phenyl azo )- bis (2- hydroxyl phenyl imine ) methylene.

Methylene diamine (0.01mole) refluxed with (0.02mole) of salicyldehyde for (2hrs), the precipitate was filtered, re crystallized from ethanol., then dried and dissolved in basic ethanol and added 4- methyl phenyl azo at (0-5)̊ C, after (48hrs), the precipitate was filtered and dried, to produce 88% of ligand (HIM).

 

Synthesis of complexes with (Zn2+) :

According to procedure(5), the hot ethanolic solution of ligand [(HIP) or (HAT) or (HIM)] respectively was added to solution of cadmium chloride (ZnCl2) in mole ratio  (metal:ligand) (1:1) respectively after stirring (1hrs), precipitates formed, dried and recrystallized to yield (82%, 84%, 83%)respectively from complexes of [(HIP) or (HAT) or (HIM)] respectively.

 

Scheme (1): preparation of ligands

 

Scheme (2): suggestion figures of complexes

 

 

RESULTS AND DISCUSSION:

All ligands and complexes were studied by many methods and techniques:

 

Study of optimal conditions of complexes :

The optimal conditions for formation of complexes with zinc ion(II) were studied in this study like calibration curves of optimal concentration of [Zn2+= (0.90X10-4M)], while concentration of ligands [0.5X10-3 M of ligand (HIM)., 0.5 X 10-3M of ligand (HIP)., 1X10-3 M of ligand (HAT)]., while optimal (PH=8) was base medium to formation of complexes by job method and mole ratio method through series solutions were prepared having a constant concentration (1X10-3 M) of Zn salt (ZnCl2) and ligand., the (M:L) ratio was determined from relationship between the absorption of observed light and mole ratio (M:L) found to be (1:1) for all complexes. Other studies of these complexes in table (1) and figs (1-4).

 

Fig(1) :Mole ratio of Complex [Zn(HIM)]

 

Fig(2): Mole ratio of Complex [Zn(HAT)]

 

Fig(3): Mole ratio of Complex [Zn(HIP)]

PH

Fig(4): Variation of PH of Complexes

 

Physical and Chemical  measurements:

The molar conductance values (0.85 -1.95) ohm-1 .mol-1.cm2 of (1X10-3m) solution in DMSO indicate that the Zn- complexes are non–electrolytic in natureTable (1)

 

The elemental analysis shown in the Table (1) indicates that the Zn–complexes [(HIP), (HIM) ,(HAT) ] have stoichiometry (Metal :Ligand) (1 :1) from results of mole ratio method.

 

I.R. – spectra shown absorption bands in ligands [(HIP), (HIM), (HAT)] at (3400 -3490) cm-1 due to phenolic hydroxyl groups(5, 11) respectively in free ligands which disappeared in spectra of their complexes indicating the coordination through phenolic oxygen moiety and oxygen of carboxyl group at bond (M–O) are (509 -582) cm-1. The I.R –spectra of (Schiff bases CH=N, Azo group -N=N-)(5, 11-16) respectively in ligands exhibit  bands  at (1643-1652 and 1486-1490)cm-1 respectively, which have been  shifted towards lower frequencies at (1620-1640 and 1490-1420) cm-1  respectively in complexes to coordination with (Zn2+) –ion.

 

The coordination through nitrogen of imine group (CH=N) and Nitrogen of (-N=N-) azo group and oxygen of hydroxyl group of phenol in complexes, table (2) and figs (5-10).

 

Table (1): physical properties & Elemental Analysis:

Ligands & Complexes

M.P

(C)0

λmax

Ω-1.Cm2.mole-1 Conductance

Calc./Found

C%

H%

N%

Zn%

(HIM) C22H20N4O2

192

395

/

70.96

70.71

5.37

5.16

15.05

15.00

/

/

(HAT) C19H15N5O6

180

382

/

55.74

55.56

3.66

3.40

17.11

17.03

/

/

(HIP) C17H16N4O4

168

374

/

63.35

63.12

4.96

4.64

17.39

17.17

/

/

[Zn(HIM)]

>250

426

0.85

60.63

60.34

4.13

4.00

12.86

12.58

15.01

14.89

[Zn(HAT)]

235

438

1.12

48.26

48.11

2.75

2.55

14.81

14.57

13.84

13.60

[Zn(HIP)]

226

415

1.90

52.93

52.72

3.63

3.38

14.53

14.39

16.96

16.81

 

Table (2) :FT.IR data (cm-1) of ligands with complexes .

Ligands & Complexes

(CH=N) imine group

(-N=N-) azo  group

(-OH)

(M-N)

(M-O)

(HIM)C22H20N4O2

1640

1490

3490

/

/

(HAT)C19H15N5O6

/

1468

3400

/

/

(HIP)C17H16N4O4

1635

/

3422

/

/

[Zn(HIM)]

1620

1430

/

480

520

[Zn(HAT)]

/

1436

/

465

550

[Zn(HIP)]

1626

/

/

460

570

Solubility of ligands in different  solvents :

Solubility of  ligands [(HAT), (HIP) ,(HIM)] tested according to table (3).

 

Table (3) :Solubility  of ligands in different solvents.

(HIM)

(HIP)

(HAT)

Solvents

+

+

+

Ethanol

+

+

+

Methanol

+

+

+

DMSO

_

_

_

Benzene

-

_

_

Dioxan

-

_

_

Chloroform

-

-

-

Carbon tetrachloride

-

-

-

Di Ethyl Ether

 

The 1H.NMR-spectra  shown in ligand:  signals at δ (8.55 -8.75) due to the  proton of azomethine(5,11) group, signals at δ (11.32  --11.33) due to protons of hydroxyl groups in phenol], and signals  at δ (7.10 -6.65) assigned to phenyl group, figs (11 and 12).

 

The suggestion Figures of complexes:

Structurally, the above data indicate that ligands [(HAT) , (HIP) ,(HIM)] are tetra dentate ligands with(Zn2+) ions via ((N-atom of azomethine, azo group and oxygen of hydroxyl group of phenol))  to form 4-coordenation complexes(5 ,11):

 

Fig (5) : FT.IR –Spectra  of  Ligand ( HIM)

 

Fig (6) : FT.IR –Spectra  of  Ligand ( HIP)

 

Fig (7) : FT.IR –Spectra  of  Ligand ( HAT)

 

Fig (8): FT.IR –Spectra of Complex[Zn ( HIM)]

 

Fig (9) : FT.IR –Spectra  of  Complex[Zn ( HIP)]

 

Fig (10) : FT.IR –Spectra  of  Complex[Zn ( HAT)]

 

Fig (11) : H.NMR–Spectra  of Ligand ( HAT)             

 

Fig (12) : H.NMR–Spectra  ofComplex [ Zn ( HIM)]   

 

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Received on 10.03.2014         Modified on 30.03.2014

Accepted on 02.04.2014         © AJRC All right reserved

Asian J. Research Chem. 7(5): May 2014; Page 530-537