Lehrstuhl für Anorganische Chemie Technischen Universität München Synthesis and Catalytic Application of Monomeric Organomolybdenum Complexes Jin Zhao Vollständiger Abdruck der von der Fakultät für Chemie der Technischen Universität München zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften genehmigten Dissertation. Vorsitzender: Univ.-Prof. Dr. K. Köhler Prüfer der Dissertation: 1. Priv. -Doz. Dr. Fritz E. Kühn 2. Univ.-Prof. Dr. Oskar Nuyken Die Dissertation wurde am 31.01.2005 bei der Technischen Universität München eingereicht und durch die Fakultät für Chemie am 10. 02. 2005 angenommen. Die vorliegende Arbeit entstand in der Zeit von Oktober 2001 bis Januar 2005 am Anorganisch-chemischen Institute der Technischen Universität München I would like to express my deep gratitude to my academic supervisor Priv. –Doz. Dr. Fritz E. Kühn For the opportunity to work in his laboratory, his continuous supervision, encouragement and confidence in me and my work. Diese Arbeit wurde durch den Deutschen Akademischen Austauschdienst gefördert. Gedruck mit Unterstützung des Deutschen Akademischen Austauschdienstes (DAAD) . To my family With deep gratitude and love Acknowledgements Acknowledgements I would like to start by expressing my deep gratitude to my academic supervisor, Priv. – Doz. Dr. Fritz E. Kühn for giving me the opportunity to work in Professor W. A. Herrmann’s research group and lead me to the organometallic and organometallic oxide chemistry and for his excellent supervision, encouragement, his continual patience and trust in me and in my work. I am also thankful for his kindness and patience to hear my German from the beginning and so help me improve my proficiency in German language. I would also like to express my appreciation to Dr. Ana Santos for introducing me into the field of epoxidation catalysis, gas chromatography and all the suggestions regarding experimental work. To Dr. Paula Ferreira I am very grateful for her kind guidance in the laboratory work and her deep patience during my first week in this institute. I am very grateful to Dr. Xiangge Zhou for his generous help with my sugar complexes chemistry and for helping me overcome the hardest time of my first research year and giving me more self- confidence in chemistry. I would like to thank Dr. Ayyamperumal Sakthivel for his engagement and continual enthusiasm for the chemistry which infected and encouraged me very much and for our fruitful cooperation on the heterogeneous catalysis. I am very thankful to my chinese colleagues in our group, Dr. Yanmei Zhang and Dr. Weisong, for their constructive disscusions on chemistry so that I can easily grasp the points. I appreciate the help of Filipe Pedro on the gas chromatography and all of the laboratory work. To Jörg Fridgen I am grateful for the helpful discussions on molybdenum chemistry and his help with the gas chromatography. I am thankful to Dr. Marta Abrantes for her passion for Molybdenum dioxo and peroxo chemistry and our harmonic cooperation on this chemistry. I would also like to express my best thank to my chinese friend, Dr. Li Yong for her kindly help with Cp chemistry. To the students, Zeming Zang and Yanan Zhai, I am thankful for their participation in my work and their hard-work in the laboratory. Dr. Herdtweck is acknowledged for the X-ray structural determinations included in this work. I am also very thankful to Mr. Barth and his co-workers for the elemental analysis and Mrs Rodica Dumitrescu for the mass spectroscopy analysis. Mrs Sabina Mühl and Mrs Georgeta Krutsch are acknowledged for her precious assistance in the performance of catalytic runs and numerous NMR measurements, as well as for their being always kind to me. A special thank Acknowledgements to Professor Janos Mink and his team for the IR and Raman spectroscopy measurements and the opportunity he gave me to visit his laboratories in Budapest and Vesprém in Hungary. Mrs Grötsch, Mrs Kaufmann, Mrs. Schuhbauer, Mrs Huber from the secretary’s office are acknowledged for their help with organization and burocratic matters. To all my former and present colleagues: Dr. Angela Sandulache, Dr. Yanmei Zhang, Dr. Jörg Fridgen, Dr. Xiange Zhou, Dr. Chi Zhang, Filipe Pedro, Dr. Wei Sui, Dr. Ayyamperumal Sakthivel, Dr. Marta Abrantes, Ahmed Hijazi and Syukri. I would like to thank for all the help in the everyday life in the laboratory and for the pleasant working atmosphere they created. I thank again my supervisor Dr. Kühn for introducing me to an international research group and giving me the opportunity to get acquainted with people from different countries and to know the different cultures and religions. I appreciate the good time we spent together very much. I am very grateful to all other the members in the Prof. Herrmann’s group for their cooperativeness and friendly help. I am thankful to Dr. Klaus Ruland for taking time for me to help me with NMR measurements. I would like to thank specially to my friends, Dr. Birgit Werner and Mr. Thomas Lindhorst for their friendly help in the organic chemistry and so much nice time we spent together over these three years. Thank Filipe Pedro, Dr. Martin Schreyer, Dr. Ayyamperumal Sakthivel and Angela Tan for many interesting talks and also the good memory they give me. My thanks go to also my Chinese colleagues and friends in Munich Yucang Liao, Chuanhua He, Dr. Xuebin Li, Dr. Huanrong Li, Dr. Zhongjing Chen, Dr. Junshan Zhang and Dr. Zhimin Dai for their always kind help. DAAD (Deutscher Akademischer Austauschdient) is acknowledged for the financial support for my Ph.D. work. Finally I would like to thank my family in China, especially my parents for their support, understanding, being so proud of my every achievement and their endless love. I am sorry for my husband that I could not be together with him these three years and could not share with him the most difficult time during his PhD work in China as I would have liked. Abbreviations Abbreviations Ac acetyl acac acetylacetonate BET Brunauer-Emmett-Teller bipy 2,2’-bipyridyl bipym bipyrimidine [BMIM]NTF2 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM]PF6 1-butyl-3-methylimidazolium hexafluorophosphate Brij 1,3-diacetoxy-1,1,3,3-tetrabutyltin oxide polyethylene glycol dodecyl ether Bu butyl Bz benzyl [C8MIM] PF6 1-octyl-3-methylimidazolium hexafluorophosphate Cp cyclopentadienyl Cp* pentamethylcyclopentadienyl Cp` substituted cyclopentadienyl ring CP MAS NMR Cross Polarization Magic Angle Spinning NMR CTABr Cetyltrimethylammonium Bromide cy cyclohexyl δ chemical shift (ppm) d doublet DAB 1,4-diaza-1,3-butadiene DME dimethoxyethane DMF N, N’-dimethylformamide DMSO dimethylsulfoxide EI Electron Ionisation Et ethyl EXAFS Extended X-Ray Absorption Fine Structure FAB Fast-Atom Bombardment GC Gaschromatograghy HMPA hexamethylphosphorotriamide Imz imidazole IR Infrared Spectroscopy L Ligand m multiplet m meta Abbreviations Me methyl MS Mass Spectroscopy Mes 2,4,6-trimethylbenzyl MTO methyltrioxorhenium (VII) NMR Nuclear Magnetic Ressonance Spectroscopy μ wave number (cm-1) o ortho OTf trifluoromethanesulfonate Pe pentane Ph phenyl Pr propyl ppm parts per million py pyridine pz pyrazolyl q quartet Solv or S solvent sym symmetric R alkyl or aryl RT or r. t. room temperature RTIL room temperature ionic liquids s singulet t triplet tame trisaminomethylethane TBHP tert-butylhydroperoxide t-BuOH tert-butanol TEM Transmission electron micrograph TGA Thermogravimetric analysis THF tetrahydrofurane TlOEt thalium ethoxide TMAOH tetramethylammonium hydroxide TMS tetramethylsilane TOF turnover number Tp hydridotris (1-pyrazolylborate) Tp* hydridotris (3, 5-dimethyl-1-pyrazolyl)borate) X halogen or methyl XANES X-ray Absorption Near Edge Structure XRD X-ray Diffraction Index Index 1. Introduction 1 1.1. Introduction 1 1.1.1. Epoxidation Catalysis 1 1.1.1.1. Epoxidation - Application and Industrial Processes 1 1.1.1.2. Asymmetric Epoxidation 5 2+ 1.1.2. MoO2 Chemistry 6 1.1.2.1. Structural Aspects 6 2+ 1.1.2.2. Synthesis and Structures of MoO2 Core Complexes 8 Solvent Adducts and Phosphoryl Ligands 9 Sulfur and sulfur-Nitrogen Ligands 10 Oxygen Donor Ligands 12 Nitrogen Donor Ligands 15 Ligands with two or three Different Donor Atoms 18 Organometallic Derivatives 22 1.1.3. Catalytic Applications of Dioxomolybdenum(VI) Complexes 27 1.1.3.1. An overview on the literature works 27 1.1.3.2. Mechanistic Considerations for the Epoxidation with Mo(VI) Complexes 29 1.1.3.3. Epoxidation with Cyclopentadienyl - Dioxomolybdenum (VI) Complexes 32 1.2. Objectives 33 1.3. References 35 2. Molybdenum(VI) cis-dioxo Complexes Bearing Sugar Derived Chiral Schiff Base Ligands and their Applications in Epoxidation Catalysis 45 2.1. Abstract 45 2.2. Introduction 45 2.3. Results and Discussion 47 2.3.1. Synthesis and spectroscopic examinations 47 2.3.2. The crystal structure of complex 8/10 and the ligands 2 and 3 51 2.3.3. Complexes 7-12 in oxidation catalysis 55 2.4. Experimental Section 56 2.4.1. Synthesis and Characterization 56 Index 2.4.2. X-ray Crystallography 61 2.4.3. Catalysis reactions with compounds 7-12 as catalysts 63 2.5. Conclusions 63 2.6. References 64 3. Molybdenum(VI) cis-Dioxo Complexes with Chiral Schiff Base Ligands and their Applications in Epoxidation Catalysis 67 3.1. Abstract 67 3.2. Introduction 67 3.3. Results and Discussion 69 3.3.1. Synthesis and spectroscopic examinations 69 3.3.2. Complexes 5-9 in oxidation catalysis 71 3.4. Experimental Section 73 3.4.1. Synthesis and Characterization 73 3.4.2 Catalysis reactions with compounds 5-9 as catalysts 76 3.5. Conclusions 76 3.6. References 77 4. Heterogenization of Chiral Schiff Base Ligated Molybdenum(VI) Complexes on Mesoporous Materials and Their Application in Catalysis 79 4.1. Abstract 79 4.2. Introduction 79 4.3. Results and Discussion 81 4.3.1.