本論文的研究包括Co(por)Ar的合成和對Ar-I鍵被Co(por)活化的机理研究。首先，一系列Co(por)Ar成功的由Co(por)和取代碘帶苯在150 ℃和氫氧化鉀的作用下合成并得到中等到高的产率。 / 其次，自由能研究表明 Co(por)對Ar-I键的活化是通过碘原子轉移進行的。相对速率k[subscript rel]从取代碘代苯和碘代苯同Co(por)的競爭反應得出。自由能關係研究表明logk[subscript rel]同取代常數σp-的哈密特相关给出一斜率為1.02的直線，表明高度離域的负电荷在苯环的增加和碘原子的π電子同對位取代基在過渡態的共軛。基于这个事实和对其它机理的排除得出Co(por)對Ar-I键的活化的機理為碘原子轉移機理。因此， Co[superscript II](ttp)首先同ArI反應形成一個直線型過渡態[Co(ttp)---I---Ar]，而後生成Co(ttp)I同一個苯自由基(Ar·)。Ar同Co[superscript II](ttp)反應生成Co(ttp)Ar，Co(ttp)I同 KOH反應生成Co[superscript II](ttp)和H₂O₂，並且Co[superscript II](ttp)同ArI繼續反應。 / This research includes the synthesis of cobalt porphyrin aryl complexes (Co(por)Ar) and mechanistic study of the aryl-iodine (Ar-I) bond activation by Co(por). First, a series of cobalt porphyrin aryl complexes, Co(por)Ar, were successfully synthesized from Co(por) and aryl iodides in moderate to high yield in the presence of potassium hydroxide at 150°C. / Second, the free energy relationship study demonstrates that Ar-I bonds are activated by cobalt porphyrin (Co(por)) through an iodine atom transfer pathway. The relative rates (k[subscript rel]) were derived from competition reactions of substituted aryl iodides and phenyl iodide with Co(por). The free energy relationship study illustrates that the krel against σp - yields linear behavior with positive slope (ρ = 1.02), suggesting that a highly delocalized negative charge builds on the aryl ring, and conjugation of π-electron density of iodine atom with para substituents occurs in the transition state. With this fact and the exclusion of other possible mechanisms, it is concluded that the mechanism of activation of Ar-I bond by Co(por) involves iodine atom transfer pathway. Thus, Co[superscript II](ttp) reacts with ArI to form a linear transition state [Co(ttp)---I---Ar], which then yields Co(ttp)I and an aryl radical (Ar·). Ar· reacts with Co(ttp) to give Co(ttp)Ar, Co(ttp)I reacts with KOH to give Co[superscript II](ttp) and H₂O₂, and Co(ttp) continues to react with ArI. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Li, Chen. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 50-55). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / Table of Contents --- p.i / Acknowledgements --- p.iv / Abbreviations --- p.v / Abstract --- p.vi / Structural Abbreviations for Porphyrins --- p.ix / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter 1.1 --- Application of Cobalt Porphyrin Complexes --- p.1 / Chapter 1.2 --- Energy Level Diagram for Cobalt Porphyrin Complexes --- p.1 / Chapter 1.3 --- Co(I) Porphyrin Chemistry --- p.2 / Chapter 1.4 --- Co(II) Porphyrin Chemistry --- p.3 / Chapter 1.5 --- Co(III) Porphyrin Chemistry --- p.5 / Chapter 1.6 --- Activation of Aryl Carbon-Halogen bond by Cobalt Complexes --- p.5 / Chapter 1.6.1 --- Definination of pathways of activation of aryl carbon-halogen bond by transition metals --- p.5 / Chapter 1.6.2 --- Bond dissociation energy (BDE) of Aryl halides --- p.6 / Chapter 1.6.3 --- Mechanism of aryl carbon-halogen bond activation by cobalt complex --- p.7 / Chapter 1.6.3.1 --- Oxidative addition --- p.7 / Chapter 1.6.3.2 --- Nucleophilic Aromatic Substitution --- p.8 / Chapter 1.6.3.3 --- Radical pathway --- p.9 / Chapter 1.7 --- Free energy relationship study of aryl-halide bond activation by transition metal complexes --- p.13 / Chapter 1.7.1 --- Oxidative addition of aryl-halide bond by transition metal complexes --- p.13 / Chapter 1.7.2 --- Aryl-halide bond acitvation by transition metal complexes via radical pathway --- p.18 / Chapter 1.8 --- Objectives of the work --- p.21 / Chapter Chapter 2 --- Mechanistic study of Bond Activation of Aryl Carbon-Iodide (C-I) Bonds by Cobalt(II) Porphyrin --- p.22 / Chapter 2.1 --- Background --- p.22 / Chapter 2.2 --- Aryl Carbon-iodide (C-I) bond Activation by Co(II) Porphyrins --- p.22 / Chapter 2.3 --- Preparation of Starting Materials --- p.23 / Chapter 2.3.1 --- Synthesis of Porphyrins --- p.23 / Chapter 2.3.2 --- Synthesis of Cobalt(II) Porphyrins --- p.23 / Chapter 2.4 --- Optimization of the reaction conditions --- p.24 / Chapter 2.4.1 --- Optimization of Substrate, Base and Additive --- p.24 / Chapter 2.4.2 --- Temperature Optimization --- p.24 / Chapter 2.5 --- Halogen Atoms Effect on the Cleavage Rates of Ph-X (X = Br, Cl) Bonds --- p.25 / Chapter 2.6 --- Substrate Scope of Base-Promoted Aryl C-I Activation by Co[superscript II](ttp) --- p.26 / Chapter 2.7 --- Porphyrin Scope --- p.27 / Chapter 2.8 --- X-Ray Data of Cobalt(III) Porphyrin Aryls --- p.28 / Chapter 2.9 --- Mechanistic Study of Aryl C-I Bond Activation by Co[superscript II](ttp) --- p.29 / Chapter 2.9.1 --- Possible Mechanistic Pathway --- p.29 / Chapter 2.9.2 --- Competition Reactions --- p.30 / Chapter 2.9.3 --- Free energy relationship study --- p.32 / Chapter 2.9.4 --- Mechanism discussion --- p.33 / Chapter 2.9.4.1 --- Nucleophilic Aromatic Substitution --- p.33 / Chapter 2.9.4.2 --- Oxiative Addition --- p.33 / Chapter 2.9.4.3 --- Radical ipso-Substitution --- p.34 / Chapter 2.9.4.4 --- Electron Transfer and Iodine Atom Transfer pathways --- p.34 / Chapter 2.10 --- Conclusions --- p.37 / Chapter Chapter 3 --- Experimental Section --- p.38 / References --- p.50 / Appendix --- p.56
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_328311 |
| Date | January 2012 |
| Contributors | Li, Chen., Chinese University of Hong Kong Graduate School. Division of Chemistry. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, bibliography |
| Format | electronic resource, electronic resource, remote, 1 online resource (ix, 72 leaves) : ill. |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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