Triply-Bonded Dimolybdenum(III) Hexaalkoxides Towards Model Catalysts [Elektronische Ressource] / Jian-Gong Ma. Betreuer: Matthias Driess

M Dassi

Informations

• Publié par: technische_universitat_berlin
• Publié le: 01 janvier 2011
• Nombre de lectures: 22
• Langue: English
• Poids de l'ouvrage: 2 Mo

Extrait

Triply-Bonded Dimolybdenum(III) Hexaalkoxides Towards
Model Catalysts

vorgelegt von
M. Sc. Chemie
Jian-Gong Ma
aus Jilin (China)

Von der Fakultät II – Mathematik und Naturwissenschaften
der Technischen Universität Berlin
Institut für Chemie
zur Erlangung des akademischen Grades

Doktor der Naturwissenschaften
- Dr. rer. nat. -
genehmigte Dissertation

Promotionsausschuss:

Vorsitzender: Prof. Dr. Reinhard Schomäcker (TU Berlin)
1. Gutachter: Prof. Dr. Matthias Driess (TU Berlin)
2. Gutachter: Prof. Dr. Thomas Braun (HU Berlin)

Tag der wissenschaftlichen Aussprache: 27-04-2011

Berlin 2011
D 83 DISSERTATION










by
M. Sc. Chemistry
Jian-Gong Ma

from Jilin (China)J.-G. Ma, Y. Aksu, L. J. Gregoriades, J. Sauer, M. Driess, “Activation of C–H Bonds
Mediated by Mo ≡Mo Moieties in Heterobimetallic Zn/O/Mo Clusters”, Dalton Trans.
2010, 39, 103.

J.-G. Ma, S. Krackl, Y. Aksu, M. Driess, “Facile Access to Homo- and Heteroleptic,
Triply-Bonded Dimolybdenum Hexaalkoxides with Unsaturated Alkoxide Ligands”,
Eur. J. Inorg. Chem. 2011, 11, 1725.
The work described in this thesis has been carried out under the guidance and
supervision of Prof. Dr. Matthias Driess at the Institut für Chemie der Technischen
Universität Berlin between February 2007 and February 2011.


I would like to give my sincere appreciation to Prof. Dr. Matthias Driess for his
continuous guidance, suggestions, discussion and encouragement throughout the
course of my thesis.
I am grateful to Prof. Dr. Thomas Braun for his acceptance of the second
commentatorship.
I am grateful to Prof. Dr. Reinhard Schomäcker for his acceptance of the chairman.
I would like to thank Dr. Yilmaz Aksu for his help, suggestions and stimulating
discussions during the course of my Ph. D work.
I owe my special thanks to my colleague Dipl. Chem. Sebastian Krackl for his
friendship and help. In addition, I am very grateful to Dr. Shenglai Yao, Dr. Yun
Xiong and Dipl. Chem. Wenyuan Wang for their help during my stay in Berlin. Also I
want to say thanks to all the members in the research group of Prof. Driess for their
help and kindness.
Acknowledgements are given to Prof. Dr. Joachim Sauer and Dr. Laurence J.
Gregoriades for cooperations and DFT calculations.
Last but not least, acknowledgements are given to Ms. Marina Borowski and Dr.
Elisabeth Irran for X-ray crystal structure determinations and solutions, Ms. Sigrid
Imme for CHN and IR measurements, Dr. Heinz-Jürgen Kroth, Dr. Jan-Dirk Epping
and Mr. Manfred Dettlaff for NMR measurements.
I heartfully thank my parents, Prof. Dr. Peng Cheng and my wife Yiwei Lv for years
of selfless support and encouragement.
This work was supported by the Cluster of Excellence “Unifying Concepts in
Catalysis” sponsored by the Deutsche Forschungsgemeinschaft (DFG). TABLE OF CONTENTS
1. INTRODUCTION.................................................................................................... 1
2. MOTIVATION ......................................................................................................... 9
3. RESULTS AND DISCUSSION ............................................................................. 11
3.1 Synthesis and Characterization of Homoleptic Triply-bonded Dimolybdenum Complexes
Mo L (L = NMe , NEt and OR) .................................................................................................... 11 2 6 2 2
3.2 Heteroleptic Triply-bonded Dimolybdenum Complexes .................................................................. 18
3.2.1 State of Knowledge ................................................................................................................ 18
3.2.2 Synthesis of the Heteroleptic Triply-bonded Dimolybdenum Hexaalkoxide
tMo (O Bu) (ONe) (7) ........................................................................................................... 19 2 2 4
t3.2.3 Molecular Structure of Mo (O Bu) (ONe) (7) ....................................................................... 23 2 2 4
3.3 Selective Oxidation of the Homoleptic and Heteroleptic Triply-bonded Dimolybdenum
Hexaalkoxides ................................................................................................................................. 25
3.3.1 State of Knowledge ................................................................................................................ 25
3.3.2 Oxidation of the Homoleptic Complex Mo (ONe) (5) by DEHA ......................................... 28 2 6
t3.3.3 Oxidation of the Homoleptic Complex Mo (O Bu) (4) by DEHA ........................................ 34 2 6
3.3.4 Mechanistic Details of the Reaction between Mo (ONe) (5) and DEHA ............................. 37 2 6
V3.3.5 Molecular Structures of Mo (O)(ONe) ( μ -ONe) (8) and MoO (ONEt ) (11) .................. 40 2 5 2 3 2 2 2
V3.3.6 Theoretical Investigation of Mo (O)(ONe) ( μ -ONe) (8) ................................................... 42 2 5 2 3
t3.3.7 Oxidation of the Heteroleptic Complex Mo (O Bu) (ONe) (7) ............................................. 44 2 2 4
t3.3.8 Molecular Structure of Mo ( μ -O)( μ -ONe) (ONe) (O Bu) (12) .......................................... 45 2 2 2 2 4 2
t3.3.9 Theoretical Investigation of Mo ( μ -O)( μ -ONe) (ONe) (O Bu) (12) .................................. 47 2 2 2 2 4 2
3.3.10 Comparison of the Oxidation of the Homoleptic and Heteroleptic Triply-bonded
Dimolybdenum Complexes ................................................................................................... 49
3.3.11 Catalytic Activity of Mo (O)(ONe) ( μ -ONe) ( 8) and 2 5 2 3
tMo ( μ -O)( μ -ONe) (ONe) (O Bu) (12) .............................................................................. 49 2 2 2 2 4 2
3.4 Heterobimetallic Mo ≡Mo/O/Zn Clusters ......................................................................................... 53
3.4.1 State of Knowledge ................................................................................................................ 53
3.4.2 Synthesis of the Asymmetric Mo ≡Mo/O/Zn Clusters Containing a “MoO Zn ” Cubane ...... 54 4 3
i3.4.3 Molecular Structures of [Mo (MeZn) ( μ -Me)( μ -CH ) (OR) ] Clusters .............................. 58 2 6 2 3 2 2 7
3.4.4 Theoretical Investigation of [Mo (MeZn) ( μ -Me)( μ -CH ) (OR) ] Clusters ........................ 61 2 6 2 3 2 2 7
3.4.5 Synthesis of the Symmetric Mo ≡Mo/O/Zn Cluster ................................................................ 66
3.4.6 Molecular Structure of [Mo (MeZn) ( μ -CH )( μ -CH ) (OR) ] (15) ..................................... 70 2 6 2 2 3 2 2 6
3.4.7 Theoretical Investigation of [Mo (MeZn) ( μ -CH )( μ -CH ) (OR) ] (15) ............................. 71 2 6 2 2 3 2 2 6
3.5 Reduction of the [Mo ≡Mo] Center in Triply-bonded Dimolybdenum Hexaalkoxides and the
Synthesis of a Lewis-Base-Free Mo Mo/Li Cluster ..................................................................... 76
3.5.1 State of Knowledge ................................................................................................................ 76
3.5.2 Synthesis of the Lewis-Base-Free Heterobimetallic Mo Mo/Li Cluster ............................. 77
n3.5.3 Molecular Structure of Li Mo Bu (16) ................................................................................ 80 4 2 8
n3.5.4 Theoretical Investigation of Li Mo Bu (16) ........................................................................ 83 4 2 8
4. SUMMARY AND CONCLUSION ....................................................................... 86
5. EXPERIMENTAL SECTION .............................................................................. 92
5.1 General Procedures ........................................................................................................................... 92
5.2 Physical Measurements .................................................................................................................... 92
5.3 Starting Materials ............................................................................................................................. 93
5.4 Synthesis of the Mo (NR ) and Mo (OR) ...................................................................................... 94 2 2 6 2 6
t5.5 Synthesis of Mo (O Bu) (ONe) (7) ............................................................................................... 100 2 2 4
V5.6 Synthesis of Mo (O)(ONe) ( μ -ONe) (8) .................................................................................... 101 2 5 2 3
5.7 Synthesis of Mo(O)(ONe) (10) and Mo(O) (ONEt ) (11) ........................................................... 102 4 2 2 2
t5.8 Synthesis of Mo ( μ -O)( μ -ONe) (ONe) (O Bu) (12) ................................................................... 104 2 2 2 2 4 2
c5.9 Synthesis of [Mo (MeZn) ( μ -Me)( μ -CH ) (OR) ] (R = Ne (13), Hex (14)) ............................... 105 2 6 2 3 2 2 7
c5.10 Synthesis of [Mo (MeZn) ( μ -CH )( μ -CH ) (O Hex) ] (15) ...................................................... 107 2 6 2 2 3 2 2 6
n5.11 Synthesis of Li Mo Bu (16) ....................................................................................................... 108 4 2 8
6. REFERENCE