Structure, organization and dynamics of functional supramolecular materials studied by solid-state NMR [Elektronische Ressource] / Ümit Akbey

Umit

Informations

• Publié par: johannes_gutenberg-universitat_mainz
• Publié le: 01 janvier 2008
• Nombre de lectures: 75
• Langue: English
• Poids de l'ouvrage: 13 Mo

Extrait

Structure, Organization and Dynamics of
Functional Supramolecular Materials
Studied by Solid-State NMR




Dissertation
Zur Erlangung des Grades
“Doktor des Naturwissenschaften”
im Promotionsfach Chemie

am Fachbereich Chemie, Pharmazie und Geowissenschaften
der Johannes Gutenberg-Universität Mainz



Ümit Akbey
Geboren in Çorum, Turkey



Mainz, (2008)





Dekan: Prof. Dr. Wolfgang Hofmeister



1. Berichterstatter: Prof. Dr. Hans W. Spiess
2. Berichterstatter:. Holger Frey




















Tag der mündlichen Prüfung: 13.11.2008





Acknowledgements




I would like to thank my research supervisor, Prof. Hans Wolfgang Spiess for all of his
inspiring advises and discussions.
I sincerely thank my advisor Dr. Robert Graf for endless NMR explanation and helpful
discussions about the projects.
I would like to thank also to Prof. Ayhan Bozkurt, Prof. Bryan Coughlin, Dr. Sergio
Granados-Focil, Prof. Virgil Percec and Prof. Peter Chu for supplying the samples and
fruitful discussions which clarify many key points.
I am grateful to all Spiess group members for supplying the friendly research environment.
Also I would like to thank to my friends Mihael Mondeshki, Mustafa Diken, and Hamit
Erdemi for their proof reading the text and for their support which I feel always.
Finally, I am forever indebted to my parents Meliha and Duran and my brother Murat for
their endless support and love in my life.


















































Contents


1. Introduction ........................................................................................................... 1
2. NMR Spectroscopy ............................................................................................... 7
2.1. Nuclear Spin Interactions ................................................................................... 9
2.1.1. Zeeman Interaction ................................................................................... 10
2.1.2. Chemical Shift ................................................................................... 11
2.1.3. Dipolar Coupling ................................................................................... 14
2.1.4. Quadrupolar Coupling ....................................................................... 16
2.2. Spherical Representation of Interaction Tensors ............................................... 19
2.3. Density Matrix Representation ....................................................................... 20
2.4. Effect of Radio-Frequency (rf) Pulses ........................................................... 21
2.5. Magic Angle Spinning (MAS) ....................................................................... 23
2.6. Basic NMR Experiments ................................................................................... 28
2.6.1. One-Pulse Experiment ....................................................................... 29
2.6.2. Cross Polarization ................................................................................... 30
2.6.3. Heteronuclear Dipolar Decoupling ........................................................... 31
2.6.4. Echo Experiments ................................................................................... 33
2.6.5. Multidimensional NMR Experiments ............................................... 34
2.7. Advanced NMR Experiments ....................................................................... 35
2.7.1. Recoupling Methods under MAS Condition ............................................... 35
2.7.2. Multiple Quantum Techniques ........................................................... 38
2.7.3. Back-to-Back as a MQ Technique for Homonuclear Dipolar
Recoupling ............................................................................................... 39
2.7.4. Double-Quantum Buildup Curves ........................................................... 41
2.7.5. Two-Dimensional Rotor-Synchronized Double-Quantum MAS Spectra ... 43
2.7.6. Spinning-Sideband Patterns ................................... 45
2.7.7. Heteronuclear Dipolar Recoupling Techniques based on REDOR ........... 48
2.7.7.1.REPT-HSQC ................................................................................... 51 Contents II

2.7.7.2.REPT-HDOR ................................................................................... 53
2.7.7.3.REREDOR ................................................................................... 54
3. Structure and Dynamics of Anhydrous Proton Conducting Triazole-Functional
Siloxane Polymer ............................................................................................... 57
3.1. General Introduction to Proton Conductors ........................................................... 58
3.2. Results ........................................................................................................... 60
13.2.1. One-dimensional H MAS & DQF MAS NMR: Structure of the System ... 62
13.2.2. Two-dimensional rotor-synchronized H DQ MAS NMR: Proton
Proximities and Order in the System in the Solid-Phase ....................... 63
1 133.2.3. Variable Temperature H & C MAS NMR: Dynamics in the System &
Chemical Exchange ................................................................................... 66
23.2.4. H NMR Results: Acidic Ring NH Dynamics ................................... 69
3.3. Discussion & Interpretation .................................................................................. 70
3.3.1. Chemical exchange of the triazole ring NH protons ................................... 70
3.3.2. The Comparison of Microscopic and Macroscopic Conductivity ........... 74
3.3.3. The activation processes monitored by selective deuteration of acidic NH
2 proton: H NMR ................................................................................... 77
3.3.4. The motional processes at the triazole ring ............................................... 79
3.3.5. Mobility of the Spacer and Backbone of the System ................................... 81
3.4. Conclusions ........................................................................................................... 82
4. Anhydrous Proton Conducting Acid-Base Poly(acrylic acid)-Poly(4-vinyl pyridine)
Polymer Blend System: A Study of Hydrogen Bonding and Proton Conduction .. 83
4.1. Introduction ........................................................................................................... 85
4.2. Materials ........................................................................................................... 86
4.3. Results ........................................................................................................... 86
1 134.3.1. Structure of the PAA-P4VP System via SQ H MAS and C CP-MAS
NMR ........................................................................................................... 86
4.3.2. Formation of the Acid-Base Polymer Complex and the Hydrogen
Bonding ............................................................................................... 89
14.3.3. H MAS DQF Spectra and the Molecular Mobility ................................... 90
14.3.4. H MAS Variable Temperature Studies of the System and Relation to
Conductivity ............................................................................................... 93
14.3.5. 2D H DQ MAS NMR Spectra: Spatial Proximities and Proton
Connectivity in Systems ....................................................................... 98 Contents III
4.3.6. Effect of Hydration to the Systems ........................................................... 103
4.3.7. Deuterium NMR Results: Molecular Level Mobility ....................... 106
24.3.7.1.Static H NMR Results ....................................................................... 107
24.3.7.2.Spinning H NMR Results ........................................................... 108
4.4. Relation of NMR Observations to Proton Conductivity ................................... 110
4.5. Conclusions ........................................................................................................... 111
5. Hydrogen Bonding and Proton Conduction of Anhydrous Poly(2,5-benzimidazole)
-Poly(vinyl-phosphonic acid) Acid-Base Polymer Blends ................................... 113
5.1. Materials ........................................................................................................... 115
5.2. Results ........................................................................................................... 116
15.2.1. One-Dimensional H MAS Spectra: Molecular Structure of the
System ……………