Investigations on reactions of metal complexes with N-donor ligands towards hydrogen peroxide [Elektronische Ressource] / vorgelegt von Thomas Nebe

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Justus-Liebig-Universität Giessen Institut für Anorganische und Analytische Chemie Investigations on Reactions of Metal Complexes with N-donor Ligands towards Hydrogen Peroxide Inaugural-Dissertation Zur Erlangung des Doktorgrades der Naturwissenschaften im Fachbereich Biologie und Chemie der Justus-Liebig-Universität Gießen vorgelegt von Thomas Nebe aus Eisenach Erstgutachter: Professor Dr. Siegfried Schindler Zweitgutachter: Professor Dr. Richard Göttlich Datum der Abgabe der Dissertation im Prüfungsamt: Datum der mündlichen Prüfung: For my family ACKNOWLEDGEMENTS Acknowledgements The work described in this thesis was carried out between October 2005 and February 2010 at the Institute for Inorganic and Analytical Chemistry at the Justus-Liebig University of Gießen under supervision of Professor Dr. Siegfried Schindler. I would like to thank Professor Dr. Siegfried Schindler for his excellent guidance, the useful scientific discussions and the financial support during these years. Furthermore I wish to thank my colleagues, friends and labmates Alexander Beitat, Tobias Hoppe, Dr. Sabrina Turba, Dr. Anja Henß, Jörg Müller, Sandra Kisslinger, Dr. Christian Würtele, Sabrina Schäfer, Jenny Friebe, Dr.

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• Published by: justus-liebig-universitat_giessen
• Published: 01 January 2010
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Justus-Liebig-Universität Giessen
Institut für Anorganische und Analytische Chemie









Investigations on Reactions of Metal Complexes with N-
donor Ligands towards Hydrogen Peroxide

Inaugural-Dissertation



Zur Erlangung des Doktorgrades der Naturwissenschaften im Fachbereich Biologie
und Chemie der Justus-Liebig-Universität Gießen










vorgelegt von

Thomas Nebe

aus

Eisenach











































Erstgutachter: Professor Dr. Siegfried Schindler
Zweitgutachter: Professor Dr. Richard Göttlich
Datum der Abgabe der Dissertation im Prüfungsamt:
Datum der mündlichen Prüfung:



















For my family




























ACKNOWLEDGEMENTS

Acknowledgements
The work described in this thesis was carried out between October 2005 and
February 2010 at the Institute for Inorganic and Analytical Chemistry at the Justus-
Liebig University of Gießen under supervision of Professor Dr. Siegfried Schindler.
I would like to thank Professor Dr. Siegfried Schindler for his excellent guidance, the
useful scientific discussions and the financial support during these years.
Furthermore I wish to thank my colleagues, friends and labmates Alexander Beitat,
Tobias Hoppe, Dr. Sabrina Turba, Dr. Anja Henß, Jörg Müller, Sandra Kisslinger, Dr.
Christian Würtele, Sabrina Schäfer, Jenny Friebe, Dr. Jörg Astner, Cornelius
Brombach, Janina Heck, Janine Will, Jonathan Becker, Lars Valentin, Sabine Löw,
Frank Mehlich, Janine Capell, Melanie Jopp, Dr. Jing-Yuan Xu and Dr. Ildikó Kerezsi
for the pleasant atmosphere in this research group.
I am very grateful to Alexander Beitat, Dr. Christian Würtele and Günther Koch for
their great support in the handling of the X-ray crystallographic measurements.
Special thanks go to Dr. Carlos Dücker-Benfer from University of Erlangen-Nürnberg
for his great help with high pressure kinetic studies.
I also want to thank all the people of the chemical department at the Justus-Liebig
University of Gießen for their support of my work.
Very special thanks go to my wife Julia and my family for their great support and
endless patience during all this years.
I LIGANDS USED
Ligands Used
Molar
Name Abbreviation Structure and Formula Mass
-1[gmol ]
N
N-Acetyl-N´,N´-bis(2-
acetyl-uns- Npyridylmethyl]ethylenediamine 284.36 penp N HN
O

C H N O 16 20 4
N
N,N-bis(2- Nuns-penp 242.32
pyridylmethyl)ethylenediamine N NH2

C H N 14 18 4
N
N,N-Dimethyl-N´,N´-bis(2- NMe -uns-penp 270.37 2pyridylmethyl)ethylenediamine N N

C H N 16 22 4
N
N,N-Dimethyl-N´,N´-bis(6-methyl-2- NMe -uns-penp 298.43 4pyridylmethyl)ethylenediamine N N

C H N 18 26 4
N
N
N-benzyl-N,N´,N´-tris(2-
N Nbztpen 423.55 pyridylmethyl)ethylenediamine
N

C H N 27 29 5
N
N N
N-methyl-N,N´-N´-tris(2- metpen 346.47
pyridylmethyl)ethylenediamine N

C H N 22 26 4
IILIGANDS USED
N N
N N
1,3-bis(N,N,N´-tris(2-pyridylmethyl-))
bz-b-tpen 768.99
N Ndiaminoethyl-benzene
N N
NN

C H N 48 52 10
N N
N N
2,6-bis(N,N,N´-tris(2-pyridylmethyl-)) OHpC-b-tpen 799.02
N Ndiaminoethyl-4-methyl-phenol
N N
NN

C H N O 49 54 10
IIIABBREVIATIONS
Abbreviations
ATR attenuated total reflectance
BPh tetraphenylborate 4
bz benzyl
d doublet (NMR)
DNA deoxyribonucleic acid
δ chemical shift (NMR)
e. g. for example (Latin: exempli gratia)
ESI electro spray ionization
EXAFS extended X-ray absorption fine structure
EtOH ethanol
IR infrared
m multiplet
MeOH methanol
MeCN acetonitrile
me methyl
MS mass spectrometry
NAD(P)H nicotinamide adenine dinucleotide phosphate
NMR nuclear magnetic resonance
OAc acetate
OTf triflate (Trifluoromethanesulfonate)
pC para cresole
RNR R2 X ribonucleotide reductase intermediate X
RT room temperature
s singlet (NMR)
t triplet (NMR)
TauD J α-ketoglutarate dioxygenase intermediate J
UV/Vis ultraviolet-visible

IVTABLE OF CONTENTS
Table of Contents
Acknowledgements ..................................................................................................... I
Ligands Used.............................................................................................................. II
Abbreviations............................................................................................................. IV
Table of Contents ....................................................................................................... V
Table of Figures........................................................................................................ XII
1 Introduction.......................................................................................................... 1
1.1 Motivation..................................................................................................... 1
1.2 The Element Cobalt...................................................................................... 1
1.3 Cobalt–Oxygen Complexes.......................................................................... 2
1.4 The Element Iron.......................................................................................... 5
1.5 Heme Iron Proteins ...................................................................................... 6
1.6 Methane Monooxygenase............................................................................ 7
1.7 “Iron-Oxygen” Adduct Complexes ................................................................ 9
1.8 Dinuclear Iron Peroxido Complexes........................................................... 10
1.9 Tripodal Tetradentate Ligands and Derivatives.......................................... 12
1.10 The Ligand Uns-penp................................................................................. 14
1.11 Mononuclear Iron Peroxido Complexes ..................................................... 17
1.12 Iron Oxido Complexes................................................................................ 20
1.13 Model Complexes for Methane Monooxygenase ....................................... 21
1.14 Projects ...................................................................................................... 23
1.14.1 Reactions of Metal Complexes with the Ligand bztpen and Derivatives
towards Hydrogen Peroxide .............................................................................. 23
1.14.2 Kinetic Investigations on Hydroperoxido Complex Formation ............. 24
1.14.3 Metal Complexes with Uns-penp and Derivatives............................... 24
2 Theory of Reaction Kinetics............................................................................... 26
2.1 The Reaction Rate ..................................................................................... 26
V TABLE OF CONTENTS
2.2 First Order Dependence............................................................................. 27
2.3 Second Order Dependence........................................................................ 28
2.4 Reactions in Equilibria................................................................................ 29
2.5 Consecutive Reactions............................................................................... 29
‡ ‡2.6 Determination of the Activation Enthalpy ΔH , the Activation Entropy ΔS ,
‡and the Activation Volume ΔV ............................................................................. 31
3 A reinvestigation of the formation of mononuclear Fe(III) peroxides using high
pressure kinetics....................................................................................................... 33
3.1 Abstract...................................................................................................... 33
3.2 Introduction ................................................................................................ 33
3.3 Experimental .............................................................................................. 35
3.3.1 Materials and Techniques ................................................................... 35
3.3.2 Kinetic Measurements......................................................................... 36
3.3.3 X-ray Crystallography.......................................................................... 36
3.3.4 Syntheses ........................................................................................... 37
3.3.4.1 Bztpen (1) .................................................................................... 37
3.3.4.2 [Fe(bztpen)(OAc)]BPh (2)........................................................... 37 4
3.3.4.3 [Co(bztpen)Cl]BF (3)................................................................... 37 4
3.3.4.4 [Co(metpen)Cl]SbF (4) ............................................................... 37 6
3.3.4.5 [Co(bztpen)(OAc)]BPh (5) .......................................................... 38 4
3.3.4.6 [Fe(bztpen)NO](triflate) (6) ......................................................... 38 2
3.4 Results and Discussion.............................................................................. 38
3.4.1 Syntheses, Characterization and Reactivity of Complexes ................. 38
3.4.1.1 Reactivity towards Nitric Oxide .................................................... 43
3.4.1.2 Kinetic Studies ............................................................................. 45
3.5 Conclusion ................................................................................................. 48
4 Supporting Information for Chapter 3 and unpublished Results ........................ 49
4.1 Supporting Material for Chapter 3 .............................................................. 49
4.1.1 Oxidation of [Fe(bztpen)Cl]ClO .......................................................... 49 4
VI TABLE OF CONTENTS
2+4.1.2 Formation of [Fe(bztpen)OOH] ......................................................... 51
4.1.3 High Pressure Kinetics........................................................................ 53
4.2 Unpublished Results related to Chapter 3.................................................. 55
4.2.1 Experimental ....................................................................................... 55
4.2.1.1 Materials and Reagents ............................................................... 55
4.2.1.2 Physical Measurement................................................................. 55
4.2.1.3 Syntheses .................................................................................... 55
4.2.2 Results and Discussion....................................................................... 57
4.2.2.1 Crystal Structure of [Fe(bztpen)Cl]OCH x 4 H O (7)................... 57 3 2
4.2.2.2 Stopped Flow Investigation on the Reaction of [Co(bztpen)Cl]BF 4
with Hydrogen Peroxide................................................................................. 58
4.2.2.3 ESIMS Solution Studies of Cobalt Rtpen Complexes and their
Reaction with Hydrogen Peroxide.................................................................. 60
4.2.2.4 Reactions of Iron(II) and Cobalt(II) Bztpen Complexes with Nitric
Oxide ..................................................................................................... 63
4.2.2.5 Stopped Flow Investigations on the Reactions of Cobalt(II) Bztpen
Complex Solutions with Nitric Oxide .............................................................. 65
5 Iron Complexes with the bridging Ligands bz-b-tpen and pC-b-tpen................. 66
5.1 Experimental .............................................................................................. 66
5.1.1 Materials and Reagents ...................................................................... 66
5.1.2 Physical Measurements ...................................................................... 66
5.1.3 Syntheses of the Ligand bz-b-tpen...................................................... 66
5.1.3.1 Formation of the Schiff-Base........................................................ 66
5.1.3.2 Reduction of the Schiff-Base........................................................ 67
5.1.3.3 Reductive Amination .................................................................... 67
5.1.4 Syntheses of the Ligand pC-b-tpen..................................................... 68
5.1.4.1 Formation of the Schiff-Base........................................................ 68
5.1.4.2 Reduction of the Schiff-base........................................................ 68
5.1.4.3 Reductive Amination .................................................................... 69
5.1.5 Syntheses of the Complexes............................................................... 69
VII