SYNTHESIS, CHARACTERIZATION AND ANTIBACTERIAL ACTIVITY OF

CU(II) AND NI(II) COMPLEXES OF

3,4,5-TRIMETHOXYBENZOYL THIOUREA LIGANDS

Norsyafikah Asyilla Binti Nordin (24506)

Bachelor of Science with Honours

(Resource Chemistry)

2012

Faculty of Resource Science and Technology

SYNTHESIS, CHARACTERIZATION AND ANTIBACTERIAL ACTIVITY OF

CU(II) AND NI(II) COMPLEXES OF

3,4,5-TRIMETHOXYBENZOYL THIOUREA LIGANDS

NORSYAFIKAH ASYILLA BINTI NORDIN (24506)

This project is submitted in partial fulfillment of

the requirements for the degree of Bachelor of Science with Honours

(Resource Chemistry)

Faculty of Resource Science and Technology

UNIVERSITI MALAYSIA SARAWAK

2011/2012

1

Synthesis, Characterization and Antibacterial Activity of Cu(II) and Ni(II) Complexes of

3,4,5-trimethoxybenzoyl Thiourea Ligands

Norsyafikah Asyilla Binti Nordin

Resource Chemistry Programme

Faculty of Resource Science and Tecnology

Universiti Malaysia Sarawak

ABSTRACT

In this study, Cu(II) and Ni(II) complexes of thiourea ligands have been synthesized. The synthesized thiourea

ligands were different according to the types of amino acids used which are glycine and phenylalanine. The

thiourea ligands and their complexes were characterized using FTIR, UV/Visible, 1H and

13C NMR spectroscopic

methods, CHN microelemental analysis, molar conductivity and melting points. The FTIR stretching vibrations

of the complexes showed significant shift compared to the stretching vibrations for the ligands. The n→π*

transition were shown for the ligands and π →π* transition were observed for the complexes. For 1H and

13C

NMR, the spectra of the complexes were shifted from the spectra of the ligands. The proposed structures for the

complexes were square planar and the ligands were coordinated to the metals through the carboxylate group.

Complex (3) showed significant activity towards the growth of E. coli with the MIC value of 92.5 ppm.

Keywords: thiourea ligands, transition metal complexes, synthesized, characterized, antibacterial activity

ABSTRAK

Dalam penyelidikan ini, kompleks Cu(II) dan Ni(II) dengan ligan tiourea telah disintesis. Ligan tiourea tersebut

telah dihasilkan melalui dua kumpulan asid amino yang berbeza iaitu glisin dan fenilalanin. Ligan tiourea

bersama kompleks yang terhasil telah dianalisis dengan menggunakan kaedah spektroskopi Fourier

Transformasi Infra-Merah (FTIR), Ultralembayung/Cahaya Nampak (UV/Visible), serta Resonans Magnetik

Nuklear (RMN) 1H dan

13C, analisis mikrounsur CHN, konduktiviti molar dan takat lebur. Regangan FTIR bagi

kompleks menunjukkan peralihan jika dibandingkan dengan nilai regangan bagi ligan. Peralihan tenaga n→π*

ditunjukkan oleh ligan manakala bagi kompleks, peralihan tenaga π→π* dapat dilihat. Untuk RMN 1H dan

13C,

spektra bagi kompleks menunjukkan nilai yang teralih berbanding spekta yang ditunjukkan oleh ligan. Struktur

bagi kompleks adalah satah persegi dan ligan adalah dikoordinasikan kepada logam melalui kumpulan

kaboksilat. Kompleks (3) menunjukkan aktiviti yang signifikan terhadap pertumbuhan E. coli dengan nilai

Kepekatan Rencatan Maksimum (MIC) pada 92.5 ppm.

Kata kunci: ligan tiourea, kompleks logam peralihan, sintesis, analisis, aktiviti antibakteria

2

CHAPTER 1

1.0 Introduction

Thiourea (Figure 1) is a compound that is produced by the replacement of oxygen atom by

sulphur atom in the urea compound (Edrah, 2010).

Thiourea derivatives have many potentials to be applied in various fields. In recent years, the

thiourea derivatives have been studied for their potential in agriculture, medicine and

analytical chemistry (Abosadiya et al., 2009). Mushtari and Yusof (2009) reported that, the

thiourea derivatives possess antitubercular, antithyroid, antihelmintic, insecticidal and

rodenticidal properties.

Yusof et al. (2010) stated that, due to the sulphur atom in the thiourea, the thiourea derivatives

can act as corrosion inhibitors agent since sulphur can be protonated in acidic solution easily.

The thiourea compound contains two nitrogen atoms and one sulphur atom which can inhibit

the metallic corrosion (Edrah & Hasan, 2010).

Besides that, thiourea compounds are able to form hydrogen bonding and have been used as

anion receptors. Biphenyl thiourea for example, can be used as carboxylate sensing (Saeed et

al., 2011). The thiourea derivatives also an effective mercury ion absorbent in aqueous

solution (Olkhovyk et al., 2005).

Figure 1: Structure of Thiourea

3

The thiourea derivatives have been used in many applications because they are versatile

ligands. They are able to coordinate with variety of transition metal elements either as

monodentate or bidentate ligands (Yusof et al., 2010).

Mushtari and Yusof (2009) reported that, the thiourea derivatives will form coordination

complexes with metal ion either by nitrogen, oxygen or sulphur atom. Furthermore, the

reaction involving thiourea derivatives can be conducted at ambient surrounding since the

thiourea is thermally stable and insensitive to air (Yusof et al., 2010).

Some of the transition metal elements which present at trace level are important for the

biological system. According to Arslan et al.(2009), the biological compounds and their metal

complexes are needed to be studied so that their function in the systems can be identified. The

ligand together with the metal complexes plays an important role as antibacterial, antifungal,

antitubercular, antithyroid, antihelmintic, rodenticidal, insecticidal and herbicidal (Arslan et

al., 2009).

There are many researches regarding the antibacterial activities of the thiourea derivatives. In

the research conducted by Zhong et al. (2008), they have proven that the acyl thiourea

derivatives showed antibacterial activities towards Escherichia coli, Pseudomonas aeruginosa,

Staphylococcus aureus and Sarcina. Antibacterial activity was also shown by benzenesulfonyl

thiourea derivatives (Faidallah et al., 2011).

4

1.1 Problem Statement

The synthesis of transition metal with 3,4,5-trimethoxybenzoyl thiourea ligand is important

since thiourea compound can be used in many applications. This is because of the properties

of the thiourea derivatives that have multiple donor atoms and can function as monodentate or

bidentate ligand. Besides that, the antibacterial activity of the complexes can be analyzed.

1.2 Objectives

1) To synthesize the 3,4,5-trimethoxybenzoyl thiourea ligands

2) To synthesize the Cu(II) and Ni(II) complexes of 3,4,5-trimethoxybenzoyl thiourea

ligands

3) To characterize the Cu(II) and Ni(II) complexes of 3,4,5-trimethoxybenzoyl thiourea

ligands using FTIR, NMR, UV-Visible spectrometer, CHN microelemental analysis,

molar conductivity and melting points

4) To evaluate the antibacterial activity of 3,4,5-trimethoxybenzoyl thiourea ligands and

their Cu(II) and Ni(II) complexes

5

CHAPTER 2

2.0 Literature Review

2.1 Thiourea Compound

According to Mushtari and Yusof (2009), thiourea and its derivatives have been used in

technological applications. They were used as catalyst and for extraction of toxic metals. They

can also act as antitubercular, antithyroid, antihelmintic, insecticidal and rodenticidal

properties (Mushtari & Yusof, 2009). Another application of thiourea derivatives is both the

ligand and the transition metal complexes have been used as plant-growth regulator (Arslan et

al., 2009). Moreover, Yesilkaynak et al. (2010) stated that, the thiourea derivatives have been

applied in liquid-liquid extraction, pre-concentration and highly efficient chromatographic

separations.

Mushtari and Yusof (2009) reported that, the thiourea derivatives will form coordination

complexes with metal ion either by nitrogen, oxygen or sulphur atom. They can also form

bonds to other donor atom that are present in the molecule. Depending on the substituent

group in the thiourea derivatives, they can act as monodentate, bidentate or polydentate ligand.

As described by Yusof et al. (2010), the substituted thiourea for example, benzoylthiourea and

phenylthiourea can form intra and intermolecular hydrogen bonding. As reported by Meyer et

al. (2010), the thiourea and its derivatives are versatile ligands in iron coordination chemistry.

The thiourea derivatives are very flexible ligand because they can coordinate to the transition

metal as neutral, monoanions or dianions. The ability of the thiourea derivatives to form multi-

bonding is depending on the atoms in the ligand which are oxygen, nitrogen and sulfur

(Yesilkaynak et al., 2010).

6

As reported by Arslan et al. (2009), the thiourea derivatives able to coordinate as neutral

ligands, monoanions or dianions to the metal centres. In their study, they have synthesized five

thiourea ligands and their nickel(II) and copper(II) complexes. The complexes were examined

for their antimicrobial activity. The synthesis of the compound involves the cyclohexane

carbonyl chloride with potassium thiocyanate in acetone which then condensed with

secondary amine. Then, purification was done using ethanol-dichloromethane mixture. The

result of their research, they found that the antimicrobial activity of the compound were lower

than other thiourea derivatives by the presence of cyclohexyl moiety in the compound.

The synthesis of the ligand is shown in Scheme 1. The HNR2 are either HN(C2H5)2,

HN(C3H7)2, HN(C4H9)2, HN(C6H5)2 or HN(C4H8)O.

R2

KSCN HNR2

C S

O

Cl N

O O

NH

N

S

Cyclohexane

carbonyl chloride

Scheme 1: Reaction of cyclohexanecarbonyl chloride with KSCN and amine

7

According to the research conducted by Yesilkaynak et al. (2010), the materials used were

different if compared to the materials used by Arslan et al. (2009). They have used aromatic

compound which was biphenyl-4-carbonyl chloride as the starting material (Yesilkaynak et

al., 2010). Similar to the method used by Arslan et al. (2009), they also mixed the starting

material with potassium thiocyanate. The mixture was refluxed and later cooled at room

temperature. Then, 6-methylpyridin-2-amine solution in acetone was added and the mixture

was stirred. To obtain acidified solution, HCl was added into the mixture. The solid product

was filtered and was purified using ethanol and dichloromethane mixture. In their study, they

found the presence of intermolecular hydrogen bonds in the compound using X-ray diffraction

(Yesilkaynak et al., 2010). The chemical reactions are shown in Scheme 2.

O

Cl N

O

SC

N NH2

Biphenyl-4-

carbonyl chloride N-(6-methylpyridin-2-yl-

carbamothioyl) biphenyl-4-

carboxamide

Scheme 2: Synthesis of N-(6-methylpyridin-2-yl-carbamothioyl) biphenyl-4-carboxamide

8

On the other hand, in order to synthesize N,N’-disubstituted thiourea ligand, benzoyl

isothiocyanate was prepared and was mixed with substituted aniline in dry acetone. The

mixture was heated and stirred. During cooling, acidified chilled water was added. The solid

formed was separated and distilled water was used to wash the solid. Then, the solid was dried

at room temperature. The thiourea derivatives were tested against the human cells to determine

the cytotoxic activity. The results showed that, the thiourea derivatives have the potential as

cytotoxic (Rauf et al., 2009). Scheme 3 shows the reactions involve in this synthesis.

A different approach was used by Saeed et al., (2011) in their research. This is because they

used acetonitrile as solvent, instead of acetone. In order to synthesize N-(biphenyl-2-

thiocarbomoyl)-4-phenylcarboxamide, they used 2-aminobiphenyl in dry acetonitrile to be

reacted with benzoyl isothiocyanate, also in acetonitrile. The mixture was then refluxed for

few hours. This study also used HCl to acidify the mixture while cooling. Water was used to

wash the solid product formed. The product was recrystallized using acetone and

dichloromethane mixture. FTIR, NMR and single crystal X-ray diffraction were used to

characterize the compound.

SOCl2heat

DMF KSCN

Acetone Acetone

RR

CSNH2

O

NH

S

NH

O O H O Cl O N

+

Scheme 3: Synthesis of N,N’-disubstituted thiourea ligand

9

In their study, they found that there were presence of intra and intermolecular hydrogen

bonding in the thiourea compound. The chemical reactions in this study are shown Scheme 4.

Apart from that, in other research which is to synthesize N-(biphenyl-4-carbonyl)-N’-(4-

chlorophenyl) thiourea, different materials were used. As explained by Yamin and Arif

(2007), 4-chloroaniline was used as the starting material. 4-chloroaniline solution in acetone

was added to biphenylcarbomoylisothiocyanate also in acetone. The mixture was then refluxed

for 3 hours and the solution was filtered. The filtrate was allowed to evaporate at room

temperature. The final product was crystals which obtained after a few days.

For the synthesis of N-(biphenyl-4-ylcarbonyl)-N’-(2-pyridylmethyl) thiourea, biphenyl 1-4

carbonyl chloride and ammonium thiocyanate mixture was refluxed for 4 hours with 2-

picolylamine (Yamin et al., 2007). After that, the mixture was filtered and allowed to

evaporate at room temperature. Black precipitate that formed after a few days was washed

with water and cold ethanol. Recrystallization was done using the mixture of dichloromethane

and n-hexane.

Dry

acetonitrile

CS N

O

NH 2

O

NH

NH

S

+

N-(biphenyl-2-thiocarbomoyl)-4-

phenylcarboxamide

Scheme 4: Synthesis of N-(biphenyl-2-thiocarbomoyl)-4-phenylcarboxamide

10

2.2 Transition Metal Complexes of Thiourea

Thiourea derivatives are very flexible compound since they have three donor atoms in the

structure which are oxygen, nitrogen and sulfur (Yesilkaynak et al., 2010). So, they are

possible to form multi-bonding. Saeed et al. (2009) have reported that, thiourea contains both

carbonyl and thiocarbonyl group and therefore, for the transition metal ions, they will act as

ambidentate donor ligands. Because of that, thiourea often use as ligand in the formation of

transition metal complexes.

According to Arslan et al. (2009), the related metal complexes were produced after the

reaction of the ligands with the metallic salts at room temperature. The thiourea ligands and

their copper(II) complexes give better antifungal activity against the tested yeast if compared

to nickel(II) complexes. M in Scheme 5 is either Ni2+

or Cu2+

.

Scheme 5: Reaction of ligands with metallic salts

R2

M

R2

R2

M

O

NH

N

S

N

N

S

O

O

N

S

N

n

2+

11

Rauf et al. (2009) have explained that, to form the metal complexes, the thiourea derivatives

was dissolved in acidified methanol and CuCl powder was added. The mixture was stirred for

few hours. The solid product formed was filtered and washed using methanol. Then, the solid

was dissolved in dichloromethane. A few amount of the solution was cooled together with

diethyl ether. The synthesis is shown in Scheme 6.

R

R

R

R

Methanol

CuCl

0.5%HCl Cu

Copper(I) complex with N,N’-

disubstituted thiourea

Scheme 6: Synthesis of copper(I) complex with N,N’-disubstituted thiourea

12

Listed below are some of the thiourea derivatives that have been synthesized by the past

researchers.

Table 1: Thiourea Derivatives

Thiourea derivatives Molecular structure Reference

N-(biphenyl-4-carbonyl)-

N’-(4-chlorophenyl)

thiourea

Yamin & Arif, 2007

N-2-(3-picolyl)-N’-(4-

chlorobenzoyl) thiourea

Mushtari & Yusof,

2009

1-(biphenyl-4-carbonyl)-3-

p-tolyl-thiourea

Arslan et al., 2004

N-(6-methylpyridin-2-yl-

carbamothioyl)biphenyl-4-

carboxamide

Yesilkaynak et al.,

2010

N-(biphenyl-4-ylcarbonyl)-

N’-(2-pyridyl-

methyl)thiourea

Yamin et al., 2007

13

Neutral ferric with thiourea

ligand

Meyer et al., 2010

Copper (I) complexes with

N,N’-disubstituted

thioureas

R

R

R

Cu

Rauf et al., 2009

14

2.3 Applications of Thiourea and Their Transition Metal Complexes

Some of the thiourea derivatives and their metal complexes have been tested for their

biological activity for example, as antimicrobial agent (Isab et al., 2010). In their research,

they have used two types of gram-negative bacteria which are Escherichia coli and

Pseudomonas aeruginosa. The complex that showed the greatest antimicrobial activity is

[(PPh3)1Ag(MeTu)2]NO3.

Other research found that, thiourea derivatives can act as antifungal agents (Fernandez et al.,

2005). In their research, they have conducted few tests to analyze the activity of pyridyl

thiourea, phenyl thiourea and trichloroethyl thiourea. According to their research, phenyl

thiourea and their p-chloro and p-nitro showed the most active antifungal activity. Besides

that, they reported that the thiourea with di-n-butyl substitution has inhibited the growth of

plant pathogens which are Pyricularia oryzae and Drechslera oryzae. Aromatic disubstitution

of thiourea also showed antifungal activity when the chloro or methyl group was at ortho

position.

Furthermore, the thiourea derivatives have been tested for their antinociceptive activity which

is used to reduce pain. For the determination of the antinociceptive compound, 1-phenyl-3-{4-

[(2E)-3-phenylprop-2-enoyl]phenyl}thiourea and urea was prepared. It has been proven that

the thiourea was more effective if compare to the urea derivatives for their antinociceptive

activity (Santos et al., 2008).

15

2.4 Antibacterial Study of Thiourea Derivatives

As explained by Zhong et al. (2008), they have used gram-positive and gram-negative bacteria

to determine the antibacterial activity of thiourea derivatives of chitosan using the

turbidimetric method. In their study, they found that the compound gives strong antibacterial

activity towards the tested bacteria which are Escherichia coli, Pseudomonas aeruginosa,

Staphylococcus aureus and Sarcina. The antibacterial activity of the thiourea derivatives of

chitosan was more effective if compared to the chitosan.

In addition, in the study conducted by Arslan et al. (2009), they tested the antibacterial

activities of the thiourea derivatives and their transition metal complexes using broth

microdilution procedures. They found that, the complexes showed antibacterial activity

towards the tested bacteria. Moreover, they stated that the antibacterial activity towards gram-

positive bacteria is greater than gram-negative bacteria.

According to Chen et al., (2005), they have prepared the thiourea chitosan silver ion complex

as an antibacterial agent. They mentioned that, the MIC of complex was determined using the

agar plate method. The MIC values were obtained from the counted colonies growth. The

complex showed much better microbial activities if compared to the chitosan, sodium

diacetate and sodium benzoate. They concluded that, the thiourea chitosan complex was

effective as antibacterial agent.

16

For the research conducted by Faidallah et al. (2011), they have successfully synthesized the

3,5-di(trifluoromethyl)-1,2,4-triazolesulfonylthiourea derivatives to investigate the

antibacterial activity of the compound. In their research, the bacteria and the testing compound

were analyzed using the UV light at 366 nm. They found that, the tested compound showed

significant effect towards antibacterial activity.

In other study conducted by El-Ayaan (2011), the antibacterial activity of the thiourea

derivatives and their platinum (II) and palladium (II) complexes have been investigated. The

test was conducted using the cup diffusion technique. Gram-negative and gram-positive

bacteria have been used in this study. In his test, DMSO was used as negative control. As a

conclusion of his study, he found that the complex showed significant antibacterial activities

towards both gram-negative and gram-positive bacteria.

17

CHAPTER 3

3.0 Materials and Synthesis

3.1 Materials

3,4,5-trimethoxybenzoyl chloride, potassium thiocyanate, glycine, phenylalanine, KOH pellet,

distilled acetone, ethanol, dichloromethane, distilled water, copper(II) acetate monohydrate

powder and nickel(II) acetate tetrahydrate powder.

3.2 Synthesis

3.2.1 Synthesis of 2-(3-(3,4,5-trimethoxybenzoyl)thioureido) acetic acid (1) and 3-phenyl-

2-(3-(3,4,5-trimethoxybenzoyl)thioureido) propionic acid (2)

For the synthesis of ligand (1), 0.01 mole (2.31 g) of 3,4,5-trimethoxybenzoyl chloride powder

was dissolved in 12 mL of distilled acetone. Then, 0.01 mole (0.97 g) of potassium

thiocyanate (KSCN) powder was dissolved in 12 mL of distilled acetone. The mixture was

also stirred for few minutes until the KSCN powder is dissolved. After that, the 3,4,5-

trimethoxybenzoyl chloride in acetone was added dropwise to the KSCN solution. The

solution was continuously stirred for an hour. The precipitate formed which is potassium

chloride (KCl) was filtered to be removed. Then, 0.01 mole (0.75 g) of glycine in 15 mL

distilled acetone was added to the filtrate solution. The mixture was refluxed for 8 hours at

temperature ranges from 65-70 oC. After the mixture had been refluxed, the solution was

filtered. The filtrate was left to evaporate at room temperature for three days. The precipitate

formed was recrystallized from ethanol/dichloromethane mixture (1:2 ratio) to give out pure

compound (1).

18

Acetone,

Reflux,

8 hours

Glycine

To synthesize ligand (2), the same method was used as in the synthesis of ligand (1) but the

amino acid used was 0.01 mole (1.65 g) of phenylalanine. The synthesis routes of ligands (1)

and (2) are shown in Scheme 7.

KSCN

3,4,5-trimethoxy benzoyl chloride

Acetone,

Stir

Scheme 7: Synthesis of ligands (1) and (2)

2-(3-(3,4,5-trimethoxybenzoyl)thioureido) acetic acid (1)

O

NH

S

NH

O

O H

H3CO

H3CO

H3CO

3-phenyl-2-(3-(3,4,5-trimethoxybenzoyl)thioureido) propionic acid (2)

O

NH

S

NH

O

O H

H3CO

H3CO

H3CO

Phenylalanine,

Acetone,

Reflux,

8 hours

19

3.2.2 Synthesis of Cu(II) and Ni(II) Complexes of Ligand (1)

1 mmole (0.33 g) of ligand (1) was dissolved in 10 mL ethanol. Then, 1 mmole (0.06 g) of

KOH pellet was added into the mixture to deprotonate the hydrogen at the carboxylic group of

the ligand. Distilled water was used to dissolve 1 mmole (0.20 g) of copper(II) acetate

monohydrate, Cu(II)(CH3COO)2.H2O powder. After that, ligand (1) solution was added into

the Cu(II) solution. The mixture was stirred for few hours. Then, the mixture was left to

evaporate for a week to give out the precipitate of Cu(II) complex of ligand (1) which is

complex (3). The precipitate formed was filtered.

Same method was used to synthesize complex (4) and different metal salts was used which

was 1 mmole (0.25 g) of nickel (II) acetate tetrahydrate, Ni(II)(CH3COO)2.4H2O powder. The

reactions involved in the synthesis of complexes (3) and (4) are shown in Scheme 8.

20

Stir

Stir

,

, Cu(II)(CH3COO)2.H2O

KOH

Ni(II)(CH3COO)2.4H2O

KOH

[2-(2-(3-(3,5,6-trimethoxybenzoyl)thioureido) acetic acid

acetato diaqua copper (II)] (3)

[2-(2-(3-(3,5,6-trimethoxybenzoyl)thioureido) acetic acid

acetato diaqua nickel (II)] (4)

Scheme 8: Synthesis of complexes (3) and (4)

Ligand (1)

Copper(II) complex of 2-(3-(3,4,5-

trimethoxybenzoyl)thioureido) acetic acid (3)

Nickel(II) Complex of 2-(3-(3,4,5-

trimethoxybenzoyl)thioureido) acetic acid (4)

21

3.2.3 Synthesis of Cu(II) and Ni(II) Complexes of Ligand (2)

1 mmole (0.42 g) of ligand (2) was dissolved in 10 mL ethanol. Then, 1 mmole (0.06 g) of

KOH pellet was added into the mixture to deprotonate the hydrogen at the carboxylic group of

the ligand. Distilled water was used to dissolve 1 mmole (0.20 g) of copper(II) acetate

monohydrate, Cu(II)(CH3COO)2.H2O powder. After that, ligand (2) solution was added into

the Cu(II) solution. The mixture was stirred for few hours. Then, the mixture was left to

evaporate for a week to give out the precipitate of Cu(II) complex of ligand (2) which is

complex (5). The precipitate formed was filtered.

To synthesize complex (6), the metal salts used was 1 mmole (0.25 g) of nickel (II) acetate

tetrahydrate, Ni(II)(CH3COO)2.4H2O powder and the method used was as the same as the

synthesis of complex (5). The reactions involved to synthesize complexes (5) and (6) are

shown in Scheme 9.

22

Stir

Stir

,

,

KOH

KOH

[3-phenyl-2-(3-(3,4,5-trimethoxybenzoyl)thioureido)

propionic acid acetato diaqua copper (II)] (5)

[3-phenyl-2-(3-(3,4,5-trimethoxybenzoyl)thioureido)

propionic acid acetato diaqua nickel (II)] (6)

Ligand (2)

Cu(II)(CH3COO)2.H2O

Ni(II)(CH3COO)2.4H2O

Scheme 9: Synthesis of complexes (5) and (6)

Copper(II) Complex of 3-phenyl-2-(3-(3,4,5-

trimethoxybenzoyl)thioureido) propionic acid (5)

Nickel(II) Complex of 3-phenyl-2-(3-(3,4,5-

trimethoxybenzoyl)thioureido) propionic acid (6)