Title page …………………………………………………………………………….. ii
Certification …………………………………………………………………….. iii
Acknowledgement ……………………………………………………………….. iv
Dedication …………………………………………………………………. v
Abstract ……………………………………………………………………… vi
List of figures ……………………………………………………………… xi
List of tables ……………………………………………………………………. xiii
Abbreviations ………………………………………………………………… xiv

Chapter ONE

1.0 Introduction ……………………………………………………… 1

Chapter TWO

2.0 Literature review ……………………………………………………………… 4
2.10 Concept of Chelation ………………………………………………………….. 4
2.11 Metal chelate complexes …………………………………………………………. 5
2.12 Ion –pair complexes …………………………………………………………….. 5
2.13 Additive complexes ……………………………………………………………….. 5
8
2.20 Chelation with β-diketones ……………………………………………………… 6
2.30 Chelation with 4-acylpyrazolones ………………………………………………… 8
2.40 Stability of metal chelates ……………………………………………………. 10
2.41 Nature of the chelating agent …………………………………………………..10
2.42 The size of the chelate ring ……………………………………………… 11
2.43 The nature of the central metal …………………………………………….. 11
2.44 The nature of the metal-ligand bond ……………………………………….. 11
2.50 Previous work done with β-diketones …………………………………… 12
2.51 Physical properties and structure elucidation ……………………………… 13
2.52 Isolation and spectroscopic studies …………………………………………. 15
2.60 Previous work on metal chelates of β-diketones ………………………………..17
2.61 The chemistry of magnesium ……………………………………………………17
2.62 Review of previous work done on magnesium chelates of β-diketones ………..19
2.70 Chemistry of cobalt ………………………………………………………19
2.71 Review of previous work done on cobalt chelates of β-diketones …………….23
2.80 The chemistry of copper ………………………………………………………..24
2.81 Previous work done on copper chelates of β-diketones …………………………26
2.90 The chemistry of zinc …………………………………………………………… 28
2.91 Previous work done on zinc chelates of β-diketones ………………………………29
9
2.92 Spectroscopic techniques used in the study of ligands and metal complexes …… 30
2.93 Ultraviolet spectroscopy ……………………………………………………… 30
2.94 Infrared spectroscopy ………………………………………………………… 31

Chapter THREE

3.0 Experimental …………………………………………………………. 33
3.1 Laboratory apparatus and equipments ……………………………………….. 33
3.2 Laboratory reagents ……………………………………………………………. 33
3.3 Synthesis of 1-phenyl-3-methyl-4-acylpyrazol-5-ones …………………………35
3.31 Synthesis of 1-phenyl-3-methyl-4-acetylpyrazol-5-ones (HPMAP) …………… 35
3.32 Synthesis of 1-phenyl-3-methyl-4-benzoylpyrazol-5-ones (HPMBP) …………… 35
3.33 Synthesis of 1-phenyl-3-methyl-4-propionylpyrazol-5-ones (HPMPRP) ……… 36
3.34 Synthesis of 1-phenyl-3-methyl-4-butyrylpyrazol-5-ones (HPMBUP) ………… 36
3.35 Synthesis of 1-phenyl-3-methyl-4-hexanoylpyrazol-5-ones (HPMCP) …………. 36
3.36 Synthesis of 1-phenyl-3-methyl-4-palmitoylpyrazol-5-ones (HPMPP) ………… 36
3.40 Synthesis of 1-phenyl-3-methyl-4-acyllpyrazolonates …………………… 36
3.41 Synthesis of 1-phenyl-3-methyl-4-acetyl-5-pyrazolonato magnesium II complex 36
3.42 Synthesis of 1-phenyl-3-methyl-4-acetyl-5-pyrazolonato copper II complex ……37
3.43 Synthesis of 1-phenyl-3-methyl-4-acetyl-5-pyrazolonato cobalt II complex …… 38
3.44 Synthesis of 1-phenyl-3-methyl-4-acetyl-5-pyrazolonato zinc II complex …… 39
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3.45 Preparation of 3M hydrochloric acid solution ……………………………………39
3.50 Physical and spectroscopic analysis …………………………………………… 42
3.51 Melting point determination …………………………………………….. 42
3.52 Conductivity measurement ……………………………………………. 42
3.53 Electronic spectra measurement ……………………………………………… 42
3.54 Infrared spectra measurement …………………………………………… 42

Chapter FOUR

4.0 Results and Discussion …………………………………………………. 43
4.10 Structure of ligands and complexes ……………………………………… 43
4.20 Physical data ………………………………………………………………….. 45
4.30 Conductivity Measurement ………………………………………………… 48
4.40 Solubility survey of ligands and complexes ………………………………… 49
4.50 Electronic spectra of ligands and complexes ………………………………….. 51
4.60 Infrared spectra of ligands and complexes …………………………………… 53
4.70 The effect of 4-acyl substituents on the infrared carbonyl stretching frequency of
metal(II) chelates of some 1-phenyl-3-methyl 4-acylpyrazolone ………………………64
4.80 Conclusion ……………………………………………………………… 69
References ……………………………………………………………….. 71
Appendices ……………………………………………………………………………… 86