TABLE OF CONTENTS
i. Title
page
ii. Certification
iii. Dedication
iv. Acknowledgement
v. Abstracts
vi. Table
of contents
vii. List
of tables
viii. List
of figures
CHAPTER ONE;
INTRODUCTION
1.1 Schiff
base
1.2 Schiff
base metal complexes
1.3 Application
of Schiff bases
1.3.1 Biological
importance of Schiff bases
1.3.2 Antibacterial
activities
1.3.3 Antifungal
activities
1.3.4 Enzymatic
Activities
1.4 Stoichiometry
1.4.1 Uses
of stoichiometry
1.4.2
Stoichiometry complexation reactions
1.5 Aim
and objective of the research
CHAPTER TWO
Literature review
CHAPTER THREE;
EXPERIMENTAL, MATERIALS & METHOD
3.1 Materials
/Apparatus
3.2
Reagents
3.3 Methods
3.3.1 Preparation
of a Schiff base ligand
3.3.1a Synthesis
ofN,N/Bis (2-hydroxylbenzylidene- 1,4-phenylenediimine and)- M
3.3.1b Synthesis
of N,N/Bis(4-dimethylbenzylidene-1,4-phenylenediimine) -N
3.3.2 Preparation of complexes
3.3.2a Synthesis ofN,N/Bis (2-hydroxylbenzylidene-1,4-phenylenediimine)-
Co(II)complexes
3.3.2b Synthesis
ofN,N/Bis (2-hydroxylbenzylidene- 1,4-phenylenediimine )- Mn(VII) complexes
3.3.2c Synthesis
ofN,N/Bis (2-hydroxylbenzylidene- 1,4-phenylenediimine )-
Mo(VII) complexes
3.3.2.dSynthesis of N,N/Bis (4-dimethylbenzylidene-1,4-phenylenediimine)-Co(II)
complexes
3.3.2e Synthesis of N,N/Bis (4-dimethylbenzylidene-1,4-phenylenediimine)-Mn(VII)
complexes
3.3.2f Synthesis
of N,N/Bis (4-dimethylbenzadehyde-1,4-phenylenediamine)Mo(VII)
complexes
3.4 Stoichiometry
of the complexes
3.5 Characterization
of the Schiff base ligands and their complexes
3.5.1 Melting/decomposition
point
3.5.2 Electronic
Spectra
3.5.3 Infrared
spectroscopy
3.5.4 Antimicrobial
Analysis
CHAPTER
FOUR; RESULT AND DISCUSSION
4.1 Physical properties
4.2 Solubility assay of the ligands and
their complexes
4.3 Stoichiometry of the complex
4.4 Reaction Scheme
4.4.1 The
reaction scheme between 1,4-phenylenediamine and 2-hydroxylbenzadehyde (M)
4.4.2 The reaction scheme between
1,4-phenylenediamine and 4-Dimethylaminobenzadehyde (N)
4.5 Electronic Spectra
4.5.1 N,N/Bis(2-hydroxylbenzylidene-1,4-phenylenediimine)-M
and their CoM, MnM, Mo2M complexes
4.5.2 N,N/Bis(4-dimethylaminobenzylidene-
1,4-phenylenediimine)-N and their CoN,
MnN, Mo2N complexes
4.6Infrared Spectra
4.8
Proposed Structures
4.9 Antimicrobial properties
CHAPTER
FIVE
Conclusions and Recommendations
REFERENCE
APPENDIX
LIST OF TABLES
Table 3.4 Volume of the Stoichiometry of the each
metal and ligand complexes
Table4.1. The physical properties of the ligand
Table 4.2 Solubility Assessment
Table 4.3 Summary of Stoichiometry results
Table 4.5 Electronic
spectra Data showing wavelength (nm), Wave number (cm-1) and
Infrared absorption frequencies (cm-1) molar absorptivity €,Lmol-1cm-1)
Table 4.6.N,N/Bis(2-hydroxylbenzylidene-1,4-phenylenediimine)-M
and their CoM, MnM, Mo2M complexes Table: 4.7 Infrared absorption
frequencies (cm-1) of N,N/Bis (4-dimethylaminobenzylidene
-1, 4-phenylenediimine)-N
Table 4.9 Theinhibition zone Diameter(nm) of the Antimicrobial activity of ligand and complexes samples against E.coli, S.typhi, S.aureus, E. feacalis, C.albicans
LIST OF FIQURES
Fig 1: General structure of Schiff bases
Fig 2: Formation of Schiff Base upon heating
Fig 3: Some classes of Schiff base ligands
Fig 4: Structure of Co(II), Cd(II) tetrahedral
geometry and Ni(II) complexes
Fig 5: structure of metal complexes
Fig 6: Schiff
base 2-{(E)-[(8-aminonaphthalen-1- yl)imino]methyl}phenol
Fig7: The geometries of metal complexes
Fig 8: Job’s curve for CoM
Fig 9: Job’s curve for MnM
Fig 10: Job’s curve for Mo2M
Fig 11: job’s Curve for CoN
Fig 12: Job’s curve for MnN
Fig 13: Job’s curve for Mo2N
Fig: 14:The reaction scheme between
1,4-phenylenediamine and 2-hydroxylbenzadehyde(M)
Fig
15: The reaction scheme between 1,4-phenylenediamine and
4-Dimethylaminobenzadehyde (N)
Fig
16 :N,N/Bis(2-hydroxylbenzylidene, 1,4-phenylenediimine) -(M)
Fig 17:N,N/Bis(2-hydroxylbenzylidene, 1,4-phenylenediimine) –Co(II) complex, CoM
Fig
18: N,N/Bis (2-hydroxylbenzylidene,
1,4-phenylenediimine)-Mn(VIII) complex, MnM
Fig
19: N,N/Bis (2-hydroxylbenzylidene,
1,4-phenylenediimine)-Mo(VIII) complex, Mo2M
Fig
20; N,N/Bis (4-dimethylaminobenzylidene, 1,4-phenylenediimine) (N)
Fig
21: N,N/Bis( 4-dimethylaminobenzylidene, 1,4-phenylenediimine)-Co(II) complexes, CoN
Fig 22: N,N/Bis(4-dimethylaminobenzylidene, 1,4-phenylenediimine)-Mn(VII) complexes, MnN
Fig
23: N,N/Bis (4-dimethylaminobenzylidene, 1,4-phenylenediimine-Mo(VII) complexes, Mo2N
CHAPTER
ONE
INTRODUCTION
1.1
SCHIFF BASES
Schiff bases are condensation products of primary amines with carbonyl compounds and they were first reported by Schiff (Cimerman et. al., 2000). The common structural feature of these compounds is the azomethine group with a general formula RHC=N-R1, where R and R1 are alkyl, aryl, cyclo alkyl or heterocyclic groups which may be variously substituted. The common structural feature of these compounds is the azomethine group with a general formula RHC=N-R1, where R and R1 are alkyl, aryl, cyclo alkyl or heterocyclic groups which may be variously substituted. These compounds are also known as anils, imines or azomethines. Several studies (Singh et. al., 1975, Perry et. al., 1988, Elmali et. al., 2000, Patel et. al., 1999, Valcarcel et. al., 1994, Spichiger et. al., 1998,Lawrence et. al., 1976)showed that the presence of a lone pair of electrons in an sp2 hybridized orbital of nitrogen atom of the azomethine group is of considerable chemical and biological importance.
A
Schiff base is a nitrogen analog of an aldehyde or ketone in which the C=O
group is replaced by C=N-R group. It is usually formed by condensation of an
aldehyde or ketone with a primary amine.The formation of a schiff base from an
aldehydes or ketone is a reversible reaction and generally takes place under
acid or base catalysis, or upon heating.
Schiff
bases are generally bidentate (1), tridentate (2), tetradentate (3) or
polydentate (4) ligands capable of forming very stable complexes with transition
metals. They can only act as coordinating ligands if they bear a functional
group, usually the hydroxyl, sufficiently near the site of condensation in such
a way that a five or six membered ring can be formed when reacting with a metal
ion.
Schiff bases derived from aromatic amines and aromatic aldehydes have a wide variety of applications in many fields, eg., biological, inorganic and analytical chemistry (Cimerman et. al.,2000 and Elmali et. al.,2000). Applications of many new analytical devices require the presence of organic reagents as essential compounds of the measuring system.
1.2 SCHIFF BASE METAL COMPLEXES
Transition metal complexes with Schiff bases have expanded enormously and embraced wide and diversified subjects comprising vast areas of organometallic compounds and various aspects of bio-coordination chemistry (Anacona et. al., 1999). The design and synthesis of symmetrical Schiff bases derived from the 1:2 step wise condensation of carbonyl compounds, with alkyl or aryl diamines and a wide range of aldehyde or ketone functionalities, as well as their metal(II) complexes have been of interest due to their preparative accessibility, structural variability and tunable electronic properties allowing to carry out systematic reactivity studies based ancillary ligand modifications. In recent years much effort has been put in synthesis and characterization of mono- and bi-nuclear transition metal complexes (Trujillo et. al., 2008).Schiff bases are used in optical and electrochemical sensors, as well as in various chromatographic methods to enable detection of enhanced selectivity and sensitivity (Valcared et. al., 1994, spichiger et. al., 1998,Lawerence et. al., 1998). Among the organic reagents actually used, Schiff bases possess excellent characteristics, structural similarities with natural biological substances, relatively simple preparation procedures and the synthetic flexibility that enables design of suitable structural properties (Patai 1970).
SYNTHESIS CHARACTERIZATION AND PRELIMINARY ANTIMICROBIAL STUDIES OF SOME SCHIFF BASE LIG ANDS AND THEIR Co(II), Mn(VII), Mo(VII) COMPLEXES
