Redox active modification of silica surfaces via silicon carbon bond formation [Elektronische Ressource] = Redox-aktive Modifizierung von Kieselgeloberflächen durch Bildung von Silizium-Kohlenstoff-Bindungen / vorgelegt von Nicolas Plumere

Stéphanie Huss

Informations

• Publié par: eberhard_karls_universitat_tubingen
• Publié le: 01 janvier 2009
• Nombre de lectures: 18
• Langue: English
• Poids de l'ouvrage: 3 Mo

Extrait

Redox-active Modification of Silica Surfaces
via Silicon-Carbon Bond Formation



Redox-aktive Modifizierung von
Kieselgeloberflächen durch Bildung von
Silizium-Kohlenstoff-Bindungen





DISSERTATION



der Fakultät für Chemie und Pharmazie
der Eberhard-Karls-Universität Tübingen

zur Erlangung des Grades eines Doktors
der Naturwissenschaften






2009


vorgelegt von
NICOLAS PLUMERE
































Tag der mündlichen Prüfung: 30. Januar 2009

Dekan: Prof. Dr. L. Wesemann
1. Berichterstatter: Prof. Dr. B. Speiser
2. Berichterstatter: Prof. Dr. L. Wesemann
3. Berichterstatter: Prof. Dr. J. Pesek

This doctoral thesis was carried at the Institut für Organische Chemie, Fakultät für Chemie
und Pharmazie, Eberhard-Karls-Universität Tübingen, Germany, under the guidance of Prof.
Dr. Bernd Speiser.

Foremost, I am indebted to Prof. Dr. Bernd Speiser, my supervisor, for his support and
excellent guidance during this research work. I thank him not only for providing me with the
lab facilities and a perfect working environment but also for his confidence and almost
unlimited freedom he has given me. I could not have learnt more about chemistry, scientific
research and communication during the course of this work.

I thank all my working group members for valuable discussions and their friendly nature. I
would like to specially thank Dr. K. Ludwig, Dr. W. Märkle, C. Tittel, Dr. F. Novak, A. Ruff,
B. Sandig, S. Benthin, J. Schaefer, T. Wener, C. Muñoz, T. Reissig and B. Rochier.

I would like to thank Prof. Dr. Hermann A. Mayer, for his comments and discussions which
proved to be very valuable for several parts of this thesis.
I thank Prof. Dr. Joseph J. Pesek for welcoming me in his laboratory at the San Jose State
University.

I thank the Deutsche Forschungsgemeinschaft (Graduiertenkolleg 441 “Chemie in
Interphasen”) and the Max-Buchner-Forschungsstiftung for generous support of my thesis.
I thank the members of the Graduiertenkolleg for the enriching cooperation and especially
Pavel Levkin and Wolfgang Leis for the many useful and stimulating discussions as well as
David Ruiz Abad, Dominik Joosten and Benjamin Dietrich for their assistance in several
experiments. I thank Prof. Dr. Klaus Albert, Prof. Dr. Lars Wesemann, Prof. Dr. Hermann A.
Mayer and Dr. Egelhaaf for making the successful cooperation with their working groups
possible.

I personally thank Prof. Dr. Wilbur H. Campbell for introducing me into the fascinating world
of scientific research and for stimulating my interests for chemistry.

Finally, I am thankful to my family and to Stephanie for their support and for the inspiration
they gave me.

Parts of this thesis are already accepted fo publication:

A. Budny, F. Novak, N. Plumeré, B. Schetter, B. Speiser, D. Straub, H. A. Mayer, M.
Reginek, Redox-active silica nanoparticles. Part 1. Electrochemistry and catalytic activity of
spherical, nonporous silica particles with nanometric diameters and covalently bound redox-
active modifications, Langmuir 2006, 22, 10605 – 10611.

N. Plumeré, B. Speiser, Redox-active silica nanoparticles Part 2. Photochemical
hydrosilylation on a hydride modified silica particle surface for the covalent immobilization
of ferrocene Electrochim. Acta. 2007, 53, 1244 – 1251.

N. Plumeré, B. Speiser, H. A. Mayer, D. Joosten and L. Wesemann, Redox-active silica
nanoparticles. Part 3. High-temperature chlorination-reduction sequence for the preparation of
silicon hydride modified silica surfaces. Chem. Eur. J., 2009, 15, 936 – 946.



Table of content

Abbreviations

Introduction .............................................................................................................................. 1

1 Stöber particles...................................................................................................................... 9
1.1 Introduction .............................................................................................................. 9
1.1.1 The Stöber process and mechanism .......................................................... 9
1.1.1.1 Hydrolysis ................................................................................ 11
1.1.1.2 Condensation............................................................................ 12
1.1.1.3 Nucleation of primary particles................................................ 12
1.1.1.4 Aggregation of primary particles ............................................. 13
1.1.1.5 Growth by monomer addition .................................................. 14
1.1.2 General properties ................................................................................... 14
1.1.2.1 Shape ........................................................................................ 15
1.1.2.2 Porosity..................................................................................... 15
1.1.2.3 Size distribution........................................................................ 15
1.1.2.4 Dimensions............................................................................... 16
1.2 Synthesis of the Stöber particles ............................................................................ 18
1.3 Characterization of the Stöber particles ................................................................. 20
1.3.1 Particle shape........................................................................................... 20
1.3.1.1 Optical microscopy .................................................................. 20
1.3.1.2 Scanning electron microscopy ................................................. 21
1.3.2 Particle size and size distribution............................................................ 23
1.3.2.1 SEM measurements.................................................................. 23
1.3.2.2 Dynamic light scattering .......................................................... 25
1.3.3 specific surface area and pore size distribution....................................... 27
1.3.3.1 Geometrical specific surface area from SEM .......................... 27
1.3.3.2 Physisorption isotherms ........................................................... 27
1.3.3.2.1 Surface area from the BET method........................... 29
1.3.3.2.2 Porosity...................................................................... 33
1.3.3.2.2.1 Micropores from the t-method ................... 33
1.3.3.2.2.2 Mesopores from the BJH method............... 34
1.4 The optimal particle size ........................................................................................ 35

2 Silicon hydride modified silica surface.............................................................................. 36
2.1 Preparation of Si–H modified silica materials ....................................................... 38
2.2 Physical properties of the Si–H modified silica materials ..................................... 40
2.2.1 Size determination by SEM and DLS ............................................................................. 41
2.2.2 Surface characterization by nitrogen adsorption-desorption isotherms .......................... 42
2.3 Chemical properties of the Si–H modified silica materials.................................... 43
2.3.1 The silicon hydride groups (Si–H).......................................................... 43
2.3.2 The silanol groups (Si–OH) .................................................................... 47
2.3.3 The nature of the T groups .................................................................... 48 H
2.3.4 Nature of the Q groups............................................................................ 50
2.3.5 The importance of the chlorination step.................................................. 52
2.3.6 Optimal reduction temperature................................................................ 55
2.2 Conclusion.............................................................................................................. 55

3 Silicon-carbon bond formation .......................................................................................... 56
3.1 Free radical initiated hydrosilylation...................................................................... 56
3.1.1 Photochemical hydrosilylation................................................................ 57
3.1.1.1 Immobilization of 10-undecylenic acid via photochemical
hydrosilylation on non-porous M materials......................... 58 SiH
3.1.1.2 Photochemical reaction of 10-undecylenic acid with the porous
M2 materials ....................................................................... 61 SiH
3.1.2 Thermal hydrosilylation .......................................................................... 61
3.1.2.