Synthesis Of Novel Schiff Base Metal Complexes Of Aminophenols As Potential Antiseptic Agents

TABLE OF CONTENTS

TITLE PAGE ii

DECLARATION iii

CERTIFICATION iv

DEDICATION v

ACKNOWLEDGEMENTS vi

TABLE OF CONTENTS viii

LIST OF TABLES xviii

LIST OF FIGURES xxiii

SCHEME OF REACTIONS xxix

EQUATIONS xxxi

LIST OF PLATES xxxi

DEFINITION OF OPERATIONAL TERMS AND ABBREVIATIONS xxxii

ABSTRACT xxxvii

CHAPTER ONE

1.0 INTRODUCTION 1

1.1 Background of Study 1

1.2 Statement of Problem 2

1.3 Aim and Objectives of Study 3

1.4 Significance of Study 4

CHAPTER TWO

2.0 LITERATURE REVIEW 5

2.1 Schiff Bases 5

2.2 Synthesis of Schiff Bases 6

2.3 Methods of Synthesizing Schiff Bases 6

2.3.1 Classical method 6

2.3.2 Water based method 7

2.3.3 Grindstone method 8

2.3.4 Microwave irradiation method 9

2.3.5 Ultrasonic irradiation method 11

2.4 Schiff Base Metal Complexes 12

2.5 Methods of Characterizing Schiff bases and their Metal Complexes 14

2.5.1 Infrared spectroscopy 14

2.5.2 1H NMR 19

2.5.3 Electronic absorption spectroscopy and magnetic

moment measurements 21

2.5.4 Thermal analysis of Schiff base metal complexes 32

2.6 Properties and Applications of Schiff Bases and Schiff Base

Metal Complexes 36

2.6.1 Photochromic properties 36

2.6.2 Fluorescence properties 39

2.6.3 Schiff bases as organic reagents 44

2.6.4 Schiff bases as coordinating ligands 46

2.6.5 Industrial application 48

2.6.6 Plant growth regulator 50

2.6.7 Biological applications of Schiff bases and metal complexes

of aminophenols 51

2.7 Biological Importance of Transition Metals of Copper and Cobalt ions 53

2.8 Structure-Activity Relationship 54

2.8.1 Effect of substituent groups on biological activity 57

2.8.2 Effect of position of substituent groups on biological activity 60

2.9 Antibacterial Agents 61

CHAPTER THREE

3.0 METHODOLOGY 64

3.1 Materials and Methods 64

3.2 Physical Measurements 64

3.3 Synthesis of 2-aminophenol Schiff Bases 65

3.3.1 Synthesis of 2-(2-methoxybenzylideneamino)phenol (L1) 65

3.3.2 Synthesis of 2-(2-chlorobenzylideneamino)phenol (L2) 65

3.3.3 Synthesis of 2-(2-nitrobenzylideneamino)phenol (L3) 66

3.3.4 Synthesis of 2-(4-methoxybenzylideneamino)phenol (L4) 66

3.3.5 Synthesis of 2-(4-chlorobenzylideneamino)phenol (L5) 67

3.3.6 Synthesis of 2-(4-nitrobenzylideneamino)phenol (L6) 67

3.4 Synthesis of 3-aminophenol Schiff Bases 68

3.4.1 Synthesis of 3-(2-methoxybenzylideneamino)phenol (L7) 68

3.4.2 Synthesis of 3-(2-chlorobenzylideneamino)phenol (L8) 68

3.4.3 Synthesis of 3-(2-nitrobenzylideneamino)phenol (L9) 69

3.4.4 Synthesis of 3-(4-methoxybenzylideneamino)phenol (L10) 69

3.4.5 Synthesis of 3-(4-chlorobenzylideneamino)phenol (L11) 70

3.4.6 Synthesis of 3-(4-nitrobenzylideneamino)phenol (L12) 70

3.5 Synthesis of 4-aminophenol Schiff bases 71

3.5.1 Synthesis of 4-(2-methoxybenzylideneamino)phenol (L13) 71

3.5.2 Synthesis of 4-(2-chlorobenzylideneamino)phenol (L14) 71

3.5.3 Synthesis of 4-(2-nitrobenzylideneamino)phenol (L15) 72

3.5.4 Synthesis of 4-(4-methoxybenzylideneamino)phenol (L16) 72

3.5.5 Synthesis of 4-(4-chlorobenzylideneamino)phenol (L17) 73

3.5.6 Synthesis of 4-(4-nitrobenzylideneamino)phenol (L18) 73

3.6 Synthesis of Copper and Cobalt Complexes from 2-aminophenol

Schiff Bases 74

3.6.1 Synthesis of bis(2-(2-methoxybenzylideneamino)phenol)

copper(II) (CuL1) 74

3.6.2 Synthesis of bis(2-(2-methoxybenzylideneamino)phenol)

cobalt(II) (CoL1) 74

3.6.3 Synthesis of bis(2-(2-chlorobenzylideneamino)phenol)

copper(II) (CuL2) 75

3.6.4 Synthesis of bis(2-(2-chlorobenzylideneamino)phenol)

cobalt(II) (CoL2) 75

3.6.5 Synthesis of bis(2-(2-nitrobenzylideneamino)phenol)

copper(II) (CuL3) 76

3.6.6 Synthesis of bis(2-(2-nitrobenzylideneamino)phenol)

cobalt(II) (CoL3) 76

3.6.7 Synthesis of bis(2-(4-methoxybenzylideneamino)phenol)

copper(II) (CuL4) 77

3.6.8 Synthesis of bis(2-(4-methoxybenzylideneamino)phenol)

cobalt(II) (CoL4) 77

3.6.9 Synthesis of bis(2-(4-chlorobenzylideneamino)phenol)

copper(II) (CuL5) 78

3.6.1.0 Synthesis of bis(2-(4-chlorobenzylideneamino)phenol)

cobalt(II) (CoL5) 78

3.6.1.1 Synthesis of bis(2-(4-nitrobenzylideneamino)phenol)

copper(II) (CuL6) 79

3.6.1.2 Synthesis of bis(2-(4-nitrobenzylideneamino)phenol)

cobalt(II) (CoL6) 79

3.7 Synthesis of Copper Complexes from 3-aminophenol Schiff Bases 80

3.7.1 Synthesis of bis(3-(2-methoxybenzylideneamino)phenol)

copper(II) (CuL7) 80

3.7.2 Synthesis of bis(3-(2-chlorobenzylideneamino)phenol)

copper(II) (CuL8) 80

3.7.3 Synthesis of bis(3-(2-nitrobenzylideneamino)phenol)

copper(II) (CuL9) 81

3.7.4 Synthesis of bis(3-(4-methoxybenzylideneamino)phenol)

copper(II) (CuL10) 81

3.7.5 Synthesis of bis(3-(4-chlorobenzylideneamino)phenol)

copper(II) (CuL11) 82

3.7.6 Synthesis of bis(3-(4-nitrobenzylideneamino)phenol)

copper(II) (CuL12) 82

3.8 Synthesis of Copper Complexes from 4-aminophenol Schiff bases 83

3.8.1 Synthesis of bis(4-(2-methoxybenzylideneamino)phenol)

copper(II) (CuL13) 83

3.8.2 Synthesis of bis(4-(2-chlorobenzylideneamino)phenol)

copper(II) (CuL14) 83

3.8.3 Synthesis of bis(4-(2-nitrobenzylideneamino)phenol)

copper(II) (CuL15) 84

3.8.4 Synthesis of bis(4-(4-methoxybenzylideneamino)phenol)

copper(II) (CuL16) 84

3.8.5 Synthesis of bis(4-(4-chlorobenzylideneamino)phenol)

copper(II) (CuL17) 85

3.8.6 Synthesis of bis(4-(4-nitrobenzylideneamino)phenol)

copper(II) (CuL18) 85

3.9 Antibacterial Studies 86

3.9.1 Bacterial strains 86

3.9.2 Disc diffusion assay 86

3.9.3 Minimum inhibitory concentration 86