Co-ordination Chemistry of Novel Tripodal Ligands Designed to Host Anions Fawaz Ahmed Saad

321 Pages·2013·31.49 MB·English

Co-ordination Chemistry of Novel Tripodal
Ligands Designed to Host Anions
Fawaz Ahmed Saad
C
ardiff
UNIVERSITY
PRIFYSGOL
C RDVP
ae i
A thesis submitted to Cardiff University in accordance with the
requirements for the degree of Doctor of Philosophy in the Faculty of
Science, School of Chemistry, Cardiff University.
2011
UMI Number: U585501
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DECLARATION
This work h been submitted in substance for any degree and is not being concurrently
submitted in ature for any degree.
(Candidate)
Date....;?./.. ..2JS.LI
STATEMENT 1
This thesis is^bejng submitted in partial fulfilment of the requirements for the degree of PhD.
Signed.. (candidate) Date ? . / 5 ? . . ............
STATEMENT 2
This thesis is tthe result of my own work investigations except where otherwise stated. Other
sources are acknowledged reference. References are appended to each chapter.
Signed (Candidate)
Date...3JQ ../..2,0.\\...........
STATEMENT 3
I hereby giv for this thesis, if accepted, to be available for photocopying and for inter-
library loan, the title and summary to be made available to outside organisations.
Signed. (Candidate)
ACKNOWLEDGMENTS
I am extremely grateful to my supervisor Dr. Angelo Amoroso for his supervision of this work
and for his continuous advice, help and encouragement throughout the project. This research
project would not have been possible without his support.
These thanks are also extended to include Dr. Simon Pope, Dr. Paul Newman and Dr. Ben Ward,
who were also available for help and advice. Big thanks should go to Dr. Abdulrazaq Alsudany
who provided inspiration and encouragement.
Special thanks are given to Dr. James Knight for always being so generous with his time and
knowledge. Honestly, I can’t imagine how the last three years would be without his support and
valuable help.
Any acknowledgment would not be complete without thanking Dr. Niek Burma for his help in
calculating the stability constant, Dr. Rob Jenkins and Robin Hicks for invaluable technical
assistance. For their help and assistance in obtaining the crystallographic data, thanks must go to
Dr. Benson Kariuki and Dr. James Knight. I am also indebted to the colleagues in the Inorganic
Chemistry department specially people in 1.124 and 1.125 for their general assistance in many
ways.
The financial support of Umm Al-Qura University, Saudi Arabia, for this work is highly
appreciated.
Lastly, I wish to express my sincere love and gratitude to my beloved parents (Ahmed) &
(Maryam), wife (Basmah), daughter (Reem) and son (Rayyan) for their patience, support,
understanding & endless love, through the duration of my study.
In the name of Allah, Most Gracious, Most Merciful
"My Lord! Increase me in knowledge"
The holy Qur'an (114)
Summary
The development of novel ligands for the complexation of transition metal ions in
inorganic chemistry is a rapidly developing field of study. The broad objective of this work is to
design novel tripodal transition metal based receptors of (TPA) frame work which can act as
hosts for small molecules (guests) e.g. fluoride and succinate. In addition, investigation into the
co-ordination chemistry of those receptors with first row transition metals were explored using
variety of characterizing techniques such as: Infrared Spectroscopy (IR), Electronic transitions
(UV-Vis), Mass Spectrometry (MS), Nuclear Magnetic Resonance (NMR), Cyclic voltammetry
(CV) and Single Crystal Diffractometer (X-Ray).
Mono, Bis and Tris thiourea tripodal ligands have been synthesised and their co­
ordination chemistry has been investigated (chapter 2, 3 and 4) as well as the binding studies of
the bisthiourea (chapter 3) to bind: fluoride and succinate using NMR titration technique.
The co-ordination chemistry of TPPA with some first row transition metals has been
studied and it was expected to show high affinity for seven coordination sphere and indeed it has
shown strong preference for mono capped octahedral geometry (chapter 5).
Contents
Abbreviations
Chapter 1: Introduction and Background Theory................................... 1
INTRODUCTION....................................................................................................................................................................2-3
Physical techniques.......................................................................................................................................................................4
Electronic transitions (UV-Vis)...............................................................................................................................................4-5
Ligand spectra................................................................................................................................................................................5
Charge transfer transitions...........................................................................................................................................................6
d-d transitions............................................................................................................................................................................6-9
Crystallography X-Ray.............................................................................................................................................................10
Single Crystal X-ray structure analysis.............................................................................................................................11-13
Cyclic Voltammetry........................ 14-16
Shape Mapping......................................................................................................................................................................17-19
Ligands classes............................................................................................................................................................................20
Tripodal tetradentate triamine ligands.....................................................................................................................................21
Tris(2-pyridylmethyl)amine (TPA)....................................................................................................................................22-24
Guest- Host molecules...............................................................................................................................................................25
Characterising supramolecular systems.............................................................................................................................26-27
Thermodynamic information....................................................................................................................................................27
Solvent effects......................................................................................................................................................................28-29
Cation binding.....................................................................................................................................................................29-31
Anion binding.......................................................................................................................................................................32-37
Aim of this work........................................................................................................................................................................37
References..............................................................................................................................................................................38-41
Chapter 2: A novel Monothiourea Tripodal Ligand; Structural,
spectroscopic and electrochemical properties of Copper (II), Zinc (II)
and Cadmium (II).........................................................................................42
INTRODUCTION...............................................................................................................................................................43-46
EXPERIMENTAL.....................................................................................................................................................................47
General......................................................................................... 47
Preparations.................................................................................................................................................................................47
Synthesis of (L1)...................................................................................................................................................................47-48
General procedure for the synthesis of metal complexes...............................................................................................48-49
RESULTS AND DISCUSSION.........................................................................................................................................50-52
Ligand Synthesis(L')...........................................................................................................................................................50-52
Synthesis of complexes.......................................................................................................................................................52-54
Spectroscopic properties of complexes.................................................................................................................. 54
Vibrational Spectroscopy.....................................................................................................................................................54-55
!H and 13C NMR of Cd complex.............................................................................................................................................55
Electronic absorption spectra..............................................................................................................................................56-58
Electrochemical studies of Cun..........................................................................................................................................59-60
Crystallographic studies......................................................................................................................................................61-62
Crystal structure of [Cu,,(L,)][C104]2.H20.CH3CN(2.1)................................................................................................62-64
Crystal structure of [Zn11 (L*)][C104]2.H20 (2.2.1).........................................................................................................65-67
Crystal structure of [Cd^L'XCK^XCHsCNMClOJ (2.3)............................................................................................67-^9
CONCLUSIONS.........................................................................................................................................................................70
REFERENCES.....................................................................................................................................................................71-73
Chapter 3: Co-ordination Behaviour of a Novel Bisthiourea Tripodal
Ligand; Structural, Spectroscopic and Electrochemical Properties of a
series of Transition Metal Complexes with Binding
Studies............................................................................................................. 74
INTRODUCTION................................................................................................................................................................75-76
EXPERIMENTAL......................................................................................................................................................................77
General.........................................................................................................................................................................................77
Synthesis of (L2)..........................................................................................................................................................................77
General procedure for the synthesis of metal complexes................................................................................................78-79
RESULTS AND DISCUSSION...............................................................................................................................................80
Ligand Synthesis (L2).................................................... 80-82
Synthesis of Complexes........................................................................................................................................................... .82
Spectroscopic Properties of Complexes...................................................................................................................................83
Vibrational Spectroscopy..........................................................................................................................................................83
!H and 13C NMR of Zn and Cd Complexes.......................................................................................................................83-84
Electronic Absorption Spectra.............................................................................................................................................85-87
Electrochemical Studies.......................................................................................................................................................87-90
Crystallographic Studies......................................................................................................................................................91-92
Crystal structure of L2...........................................................................................................................................................93-94
Crystal structure of [Mnn(L2)(C104)][C104].2(H20) (3.1).............................................................................................94-97
Crystal structure of [Con(L2)][C104]2 (3.2)....................................................................................................................98-100
Crystal structure of [Nin(L2XC104KCH3CN)][C104].0.5(CH3COCH3).0.5(H20) (3.3).........................................101-103
Crystal structure of [Cun(L2)][C104]2 (3.4)...................................................................................................................104-106
Crystal structure of [Znn(L2)][C104]2.2(CH3CN) (3.5)................................................................................ 107-109
Crystal structure of [Cdn(L2XC104)][C104].CH3CN (3.6)..........................................................................................110-112
Crystal structure of [Mnn(L XCH30)][C104]2 (3.7)....................................................................................................113-117
Binding studies.................................................................................................................................................................118-121
EXPERIMENTAL...................................................................................................................................................................122
RESULTS AND DISCUSSION.....................................................................................................................................123-127
Titration of [ZnL2]2+ and [CdL2]2+ with fluoride..................................................................................................................128
Titration of [ZnL2]2+ and [CdL2]2+ with succinate.......................................................................................................128-133
CONCLUSIONS..............................................................................................................................................................134-136
REFERENCES.................................................................................................................................................................137-140
Chapter 4: A Tristhiourea Tripodal Framework: Co-ordination
behaviour, Structural, spectroscopic and electrochemical properties of
a series of transition metal complexes.....................................................141
INTRODUCTION...........................................................................................................................................................142-145
EXPERIMENTA.....................................................................................................................................................................145
General.......................................................................................................................................................................................145
Synthesis of (L3)...............................................................................................................................................................145-146
General procedure for the synthesis of metal complexes............................................................................................146-147
RESULTS AND DISCUSSION.............................................................................................................................. 148
Ligand Synthesis (L3)......................................................................................................................................................148-150
Synthesis of complexes............................................................................................................................................................150
Spectroscopic properties of complexes..................................................................................................................................151
Vibrational spectroscopy..........................................................................................................................................................151
*H NMR of Zn and Cd complexes.................................................................................................................................151-152
Electronic absorption spectra..........................................................................................................................................153-155
Electrochemical studies...................................................................................................................................................156-158
Crystallographic studies..................................................................................................................................................159-160
Crystal structure of [Mnn(L3)][C104]2.CH3CN (4.1)...................................................................................................161-164
Crystal structure of [Niu(L3XCH3CN)][ClO4]2.3.5(CH3CN).0.5(H2O) (4.3)..........................................................164-166
Crystal structure of [Znn(L3)][C104]2.CH3CN.CHCl3 (4.5).......................................................................................167-169
Crystal structure of [Znn(L3)][C104]2.1.5(CH3CN).0.5(H20) (4.5.1)........................................................................170-172
Crystal structure of [Cdn(L3)][C104]2.0.5(H20) (4.6)..................................................................................................173-175
Addition of dihydrophosphate to Cdn-L3...............................................................................................................................176
REFERENCES..................................................................................................................................................................177-178
Chapter 5: Co-ordination behaviour of TPPA Tripodal Ligand:
Spectroscopic, Electrochemical properties and Structural Exploration
of some Transition Metal Complexes...................................................... 179
INTRODUCTION.............................................................................................................................................................180-182
Seven co-ordinate geometry............................................................................................................................................182-183
Pentagonal Bipyramid...............................................................................................................................................................184
Capped Octahedron...........................................................................................................................................................184-185
Capped Trigonal Prism.....................................................................................................................................................185-186
Trigonal base - Tetragonal base.............................................................................................................................................187
EXPERIMENTAL....................................................................................................................................................................188
General........................................................................................................................................................................................188
Synthesis of (L4)................................. 188
General Procedure for the Synthesis of Metal Complexes..........................................................................................188-190
RESULTS AND DISCUSSION.............................................................................................................................................191
Ligand synthesis (L4)................................................................................................................................................................191
Synthesis of ligand and complexes.........................................................................................................................................192
Spectroscopic properties of complexes..................................................................................................................................192
Vibrational spectroscopy.................................................................................................................................................192-193
*H NMR of Zn and Cd complexes..................................................................................................................................193-194
Electronic absorption spectra...........................................................................................................................................195-196
Electrochemical studies....................................................................................................................................................197-198
Crystallographic studies.................................................................................................................................................199-200
Crystal structure of [Mnu(L4)][C104][Br].CH3CN (5.1).............................................................................................201-202
Crystal structure of [Fen(L4)][C104][Br].CH3CN (5.2)..............................................................................................202-203
Crystal structure of [Co11 (L4)][Br]2.0.5(H2O).2(CH3CN) (5.3)................................ 204-205
Crystal structure of [Nin(L4][C104], 67[Br]033.0.67(H2O) (5.4).................................................................................205-206
Crystal structure of [Znn(L4)][C104]2.2(CH3CN) (5.5)..............................................................................................207-208
Crystal structure of [Znn(L4)Cl2] (5.6).........................................................................................................................208-210
Crystal structure of [Zn^^ZnLlo s[I] (5.7).....................................................................................................................211
Crystal structure of [Cdn(L4)][C104]2.Na(C104).H20 (5.8)........................................................................................212-213
Structural Analysis....................................................................................................................................................................214
CONCLUSIONS.......................................................................................................................................................................216
REFERENCES.................................................................................................................................................................217-218
Appendix 1: Attempted work....................................................................219
INTRODUCTION....................................................................................................................................................................220
EXPERIMENTS AND DISCUSSION..................................................................................................................................221
Cleaving of L2...........................................................................................................................................................................221
Bromination of methyle groups......................................................................................................................................222-223
Growing metal complex crystals of L1, L2 and L3.......................................................................................................224-225
Preparation of bis phenyl urea tripodal ligand..............................................................................................................226-227
Preparation of tris benzoyl urea tripodal ligand...........................................................................................................228-229
Preparation of l,3-(dibenzoylthiourea) pyridine.........................................................................................................230-231
Converting bisthiourea tripodal ligand into urea using oxone....................................................................................232-233
REFERENCES.........................................................................................................................................................................234
Appendix 2: Publications...........................................................................235
Appendix 3: Crystals data,.................................................................236-310
Abbreviations
TP A Tris(2-pyridylmethyl)amine
MAPA Mono(6-amino-2-pyridylmethyl)(2-pyridylmethyl)amine
MPPA Mono(6-pivaloylamino)(2-pyridylmethyl)amine
BAPA Bis(6-amino-2-pyridylmethyl)(2-pyridylmethyl)amine
BPPA Bis(6-pivaloylamino)(2-pyridylmethyl)amine
TAPA Tris(6-amino-2-pyridylmethyl)amine
TPPA Tris(6-pivaloylamino)(2-pyridylmethyl)amine
TREN Tris(2-aminoethyl)amine
EDTA Ethylene diamine tetra acetic acid
CV Cyclic Voltammetry
UV-Vis Ultraviolet-visible
NMR Nuclear Magnetic Resonance
Eq Equivalent
MeCN Acetonitrile
A Angstrom
At Aromatic
Br Broad
13C Carbon 13 isotope
J Coupling constant
A Crystal field splitting
°C Degrees centigrade
CD CN Deuterated acetonitrile
3
CDCI Deuterated chloroform
3
D O Deuterated water
2
DCM Dichloromethane
DMSO Dimethylsulfoxide
EtOH Ethanol
D Doublet
eV Electron volt
ESMS Electrospray ionisation mass spectrometry
CFSE Crystal field stabilisation energy
□ Extinction coefficient
G Grams
Hz Hertz
HRMS High resolution mass spectrometry
Hr Hour
IR Infrared
kJ Kilojoule
L Litre/ligand
MS Mass spectrometry
m/z Mass/charge ratio
MHz Mega hertz
M Metal/Molar concentration