Schiff Base Metal Complexes Synthesis and Applications

Schiff bases are compounds created from a condensed amino compounds, which frequently form complexes with metal ions. They have diverse applications in biology, catalysis, material science and industry. Understanding these compounds, their properties, and the available methods for synthesizing them is a key to unlocking industrial innovation.

Schiff Base Metal Complexes provides a comprehensive overview of these compounds. It introduces the compounds and their properties before discussing their various synthesizing methods. A survey of existing and potential applications gives a complete picture and makes this a crucial guide for researchers and industry professionals looking to work with Schiff base complexes.

Schiff Base Metal Complexes readers will also find:

• A systematic and organized structure designed to make information instantly accessible
• Detailed coverage of thermal synthesis, photochemical synthesis, and more
• Challenges with different methods described in order to help readers make the correct choice for their own work

Schiff Base Metal Complexes is a useful reference for organic chemists, materials scientists, and researchers or industry professionals working with organometallics.

Preface xi

Part I Introduction 1

1 Historical Background 3
Anmol Singh, Himadri Priya Gogoi, and Pranjit Barman

1.1 Introduction 3

1.2 Theories of Coordinate Bond 4

1.2.1 Valence Bond Theory 4

1.2.2 Crystal Field Theory 4

1.2.3 Molecular Orbital Theory 5

1.2.4 Ligand Field Theory 6

References 7

2 Classification 9
Anmol Singh, Himadri Priya Gogoi, and Pranjit Barman

2.1 Ligands 9

2.2 Schiff Base 9

2.3 Types of Schiff Base 12

2.3.1 Salen-type Ligands 12

2.3.2 Salophen-type Ligands 12

2.3.3 Hydrazone-type Ligands 12

2.3.4 Thiosemicarbazone/Carbazone-type Ligands 13

2.3.5 Heterocyclic Schiff Bases 14

2.4 Different Bonding Modes of Schiff Bases 14

2.4.1 Monodentate 14

2.4.2 Bidentate 15

2.4.3 Tridentate 15

2.4.4 Tetradentate 16

2.4.5 Pentadentate 17

2.4.6 Hexadentate 17

References 17

3 Different Routes of Synthesis 23
Anmol Singh, Himadri Priya Gogoi, and Pranjit Barman

3.1 Formation of Schiff Bases 23

3.1.1 Direct Ligand Synthesis 24

3.1.2 Template Synthesis 25

3.1.3 Rearrangement of Heterocycles (Oxazoles, Thiazoles, etc.) 26

References 26

4 Schiff Base Metal Complexes 29
Anmol Singh, Himadri Priya Gogoi, and Pranjit Barman

References 34

5 Effect of Different Parameters on Schiff Base and their Metal Complex 37
Anmol Singh, Himadri Priya Gogoi, and Pranjit Barman

5.1 Ionic Charge 37

5.2 Ionic Size 37

5.3 Nature of Central Metal Ions 37

5.4 Nature of the Ligand 37

5.4.1 Basic Character of the Ligand 38

5.4.2 Size and Charge of the Ligand 38

5.4.3 Concentration of Ligand 38

5.4.4 Substitution Effect 38

5.4.5 Chelating Effect 39

5.4.6 Nature of Solvent 39

5.4.7 Crystal Field Effect 39

5.4.8 Thermodynamic and Kinetic Effect 39

References 40

6 Thioether and Chiral Schiff Base 41
Anmol Singh, Himadri Priya Gogoi, and Pranjit Barman

6.1 Thioether Schiff Base 41

6.2 Chiral Schiff Base 44

References 45

Part II Synthesis 53

7 General Routes of Synthesis 55
Himadri Priya Gogoi, Anmol Singh, and Pranjit Barman

7.1 Introduction 55

7.2 Mechanism of the Synthesis of Schiff Base Ligand 56

7.3 Problems Found in Conventional Method – Hydrolysis of C=NBond 59

References 59

8 Different Route of Synthesis of Schiff Base-Metal Complexes 61
Himadri Priya Gogoi, Anmol Singh, and Pranjit Barman

8.1 Introduction 61

8.2 Different Chemical Routes 61

8.2.1 Preparation of Schiff’s Bases via Aerobic Oxidative Synthesis 61

8.2.2 Synthesis of Schiff Bases via Addition of Organometallic Reagents to Cyanides 61

8.2.3 Reaction of Phenol with Nitriles to Form SB 62

8.2.4 Reaction of Metal Amides to Ketone to Form SB 63

8.2.5 Reaction of Nitroso Compounds with Active Hydrogen Compounds 63

8.2.6 Dehydrogenation of Amines 64

8.2.7 Oxidation of Metal Amines to Form SB 64

8.2.8 Reduction of Carbon–Nitrogen Compounds 65

8.2.9 Synthesis of SB from Ketals 65

8.2.10 SB Synthesis by Using Hydrazoic Acid 66

8.2.11 SB Synthesis by Using Sodium Hypochlorite 66

8.2.12 Preparation of N-metallo Imines 66

8.2.13 Preparation of N-metallo Imines (Metal = B, Al, Si, Sn) 67

8.2.13.1 Preparation of N-boryl and N-aluminum Imines 67

8.2.13.2 Preparation of N-silylimines via 67

8.2.13.3 Preparation of N-tin Imines 68

8.3 Different Methods 68

8.3.1 Classical or Conventional Method 69

8.3.2 Microwave Irradiation Method 70

8.3.3 Water as Solvent Method 71

8.3.4 Grindstone Technique 71

8.3.5 Ultrasonic Method 72

8.3.6 Green Method Using Green Catalyst 73

References 76

9 Synthesis and Mechanism of Schiff Base-Metal Complexes 79
Himadri Priya Gogoi, Anmol Singh, and Pranjit Barman

9.1 Introduction 79

9.2 Synthesis of Schiff Bases Metal Complexes 79

9.2.1 Synthesis of Ligand Followed by Complexation 79

9.2.1.1 One-Step Process or Template Synthesis 80

9.3 Synthesis of Some of the Schiff Base Metal Complexes 83

References 86

10 Synthesis and Mechanism of Chiral and Achiral Schiff Base and Their Metal Complexes 89
Himadri Priya Gogoi, Anmol Singh, and Pranjit Barman

10.1 Introduction 89

10.2 Synthesis of Chiral and Achiral SB Ligand 90

10.3 Synthesis of Chiral SB Metal Complexes 93

10.4 Chiral Schiff Bases of Titanium, Zirconium, and Vanadium 95

10.5 Chiral Schiff Bases of Main Group Metals 96

10.5.1 Manganese and Chromium Schiff Bases 97

10.5.2 Iron and Ruthenium Schiff Base Complexes 98

10.5.3 Cobalt, Nickel, Copper, and Zinc Schiff Base Complexes 98

10.5.4 Lanthanide Metal Schiff Bases 99

10.5.5 Silicon and Tin Metal Schiff Bases 99

References 102

11 Synthesis and Mechanism of Thioether: Schiff Base and Their Metal Complexes 105
Himadri Priya Gogoi, Anmol Singh, and Pranjit Barman

11.1 Introduction 105

11.2 Chemical Synthesis Procedures 106

11.2.1 Procedure for the Synthesis of Thioether-Containing Schiff Base 106

References 111

12 Computational Chemistry 113
Anmol Singh, Himadri Priya Gogoi, and Pranjit Barman

12.1 Introduction 113

12.2 Application of DFT in the Field of Schiff Base and Their Metal Complexes 115

References 118

Part III Application 119

13 General Applications of Schiff Bases and Their Metal Complexes 121
Anmol Singh, Himadri Priya Gogoi, and Pranjit Barman

13.1 Catalyst 121

13.2 Biological and Medicinal Importance 122

13.2.1 Antibacterial Activity 122

13.2.2 Anticancer and Anti-inflammatory Agent 122

13.2.3 Antifungal Activity 123

13.2.4 As a Drug in a Number of Diseases 123

13.3 Coatings 123

13.4 Analytical Chemistry 123

13.5 Dyes 124

13.6 Semi-conducting Materials 124

13.7 Solar System 124

13.8 Photocatalyst 125

13.9 Polymer Chemistry 125

13.10 Agrochemical Industry 125

References 125

14 Application in Pharmacological Field 129
Parnashabari Sarkar, Sourav Sutradhar, and Biswa Nath Ghosh

14.1 Introduction 129

14.2 Antimicrobial Activity 135

14.2.1 Schiff Bases Against Gram-Positive Bacteria 135

14.2.2 Schiff Bases Against Gram-Negative Bacteria 137

14.3 Antifungal Activity of Schiff Bases 138

14.4 Anticancer Activity of Schiff Bases and Their Metal Complexes 139

14.4.1 In Vitro Activity 139

14.4.2 In Vivo Activity 140

14.5 Antidyslipidemic and Antioxidant Activity 141

14.6 Anthelmintic Activity 141

14.7 Antitubercular Activity 142

14.8 Antidepressant Activity 142

14.9 Anticonvulsant Activity 142

14.10 Antioxidant Activity 142

14.11 Antiviral Activity 143

14.12 Anti-inflammatory and Analgesic Activities 143

References 143

15 Application as Catalyst 149
Saravanan Saranya and Seenuvasan Vedachalam

15.1 Introduction 149

15.2 Coupling Reaction 149

15.3 Polymerization Reaction 151

15.4 Oxidation Reaction 152

15.5 Epoxidation Reaction 153

15.6 Ring-Opening Epoxidation Reaction 154

15.7 Cyclopropanation Reaction 155

15.8 Hydrosilylation Reaction 156

15.9 Hydrogenation Reaction 157

15.10 Aldol Reaction 158

15.11 Michael Addition Reaction 159

15.12 Annulation Reaction 160

15.13 Diels–Alder Reaction 161

15.14 Click Reaction 161

15.15 Mannich Reaction 162

15.16 Ene Reaction 163

15.17 Summary 164

References 164

16 Application as Drug-Delivery System 169
Anmol Singh, Himadri Priya Gogoi, and Pranjit Barman

References 173

17 Chemosensors/Bioimaging Applications 179
K. Sekar, K. Suganya Devi, T. Dheepa, and P. Srinivasan

17.1 Introduction 179

17.1.1 Chemosensing 179

17.1.1.1 Explosives Sensing 179

17.1.1.2 Oxygen Sensing 180

17.1.1.3 High pH Sensing 180

17.1.1.4 Other Porphyrinoid-based Chemosensors and Chemodosimeters 180

17.1.1.5 Metal Sensing 180

17.2 Chemosensors 181

17.2.1 Fluorescence ON-OFF 184

17.2.1.1 Tiny Molecules Chemosensors 184

17.2.1.2 Supramolecular Chemosensors 184

17.2.1.3 QDs-based Chemosensors 184

17.2.1.4 Fluorescent Nanomaterial-based Chemosensors 185

17.2.2 OFF-ON Chemosensors 185

17.2.2.1 Rhodamine-based Sensors 185

17.2.2.2 Coumarin-based Sensors 186

17.2.2.3 BODIPY-based Sensors 186

17.2.3 Ratiometric Fluorescent Chemosensors 186

17.2.3.1 Pyrene-based Chemosensors 186

17.2.3.2 Fluorophore Hybridization Chemosensors 186

17.2.3.3 Dual-emission Fluorescent Nanoparticles 186

17.2.4 Rhodamine-based Sensors 187

17.2.4.1 Fluorescent Bioimaging of CK in HeLa cells 187

17.2.4.2 Mice Bioimaging Experiments 187

17.2.5 Fluorescent Chemosensor for AcO − Detection 189

17.2.6 CN − and Al 3+ Chemosensor for Bioimaging 191

17.3 Conclusion 192

References 192

18 Application in Industrial Field 195
M. Chakkarapani, M.A. Asha Rani, G. Saravana Ilango, and Pranjit Barman

18.1 Introduction 195

18.2 Current Status in India 198

18.3 Conclusion 199

References 200

Index 203

Pranjit Barman, PhD, is Professor of Chemistry at the National Institute of Technology, Silchar, Assam, India. He has published widely on organometallics and related areas of research.

Anmol Singh is a Research Scholar at the National Insitute of Technology, Silchar, Assam, India, studying Schiff bases and organometallics.