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dc.contributor.advisor남원우-
dc.contributor.authorSong, Yoon Ju-
dc.creatorSong, Yoon Ju-
dc.date.accessioned2016-08-25T01:08:03Z-
dc.date.available2016-08-25T01:08:03Z-
dc.date.issued2005-
dc.identifier.otherOAK-000000010488-
dc.identifier.urihttps://dspace.ewha.ac.kr/handle/2015.oak/172292-
dc.identifier.urihttp://dcollection.ewha.ac.kr/jsp/common/DcLoOrgPer.jsp?sItemId=000000010488-
dc.description.abstractThere has been an intriguing, current controversy on the involvement of multiple oxidizing species in oxygen transfer reactions by cytochromes P450 and iron porphyrin complexes. The primary evidence for the “multiple oxidants” theory was that products and/or product distributions obtained in the catalytic oxygenations were different depending on reaction conditions such as catalysts, oxidants, and solvents. In the present work, a detailed mechanistic studies on competitive olefin epoxidation, alkane hydroxylation, and C=C epoxidation versus allylic C-H hydroxylation in olefin oxygenation were carried out with in situ-generated oxoiron(IV) porphyrin π-cation radicals (1) under various reaction conditions. Based on such studies, it was observed that products and product distributions were markedly different depending on reaction conditions. For example, 1 bearing different axial ligands showed different product selectivities in competitive epoxidations of cis- and trans-olefins and of styrene and para-substituted styrenes. The hydroxylation of ethylbenzene by 1 afforded different products such as 1-phenylethanol and ethylbenzoquinone, depending on the axial ligands of 1 and substrates. Moreover, the regioselectivity of C=C epoxidation versus C-H hydroxylation in the oxygenation of cyclohexene by 1 changed dramatically depending on reaction temperatures, the electronic nature of iron porphyrins, and substrates. These results demonstrate that 1 can exhibit diverse reactivity patterns under different reaction conditions, leading to propose that the different products and/or product distributions observed in the catalytic oxygenation reactions by iron porphyrin models might not arise from the involvement of multiple oxidizing species but from 1 under different circumstances. The present study provides strong evidence that 1 can behave like a “chameleon oxidant” that changes its reactivity and selectivity under the influence of environmental changes.;The reactions of manganese(Ⅲ) porphyrin complexes with terminal oxidants such as mchloroperbenzoic acid, iodosylarenes, and H₂O₂ in the presence of base produced manganese(V)-oxo porphyrins in organic solvents at room temperature. The manganese(V)-oxo porphyrins were characterized with various spectroscopic techniques such as UV-vis, EPR, electrospray ionization mass spectrometer, ¹H NMR, and resonance Raman spectroscopy. The [(Porp)Mn^(V)=O]^(+) species were stable at room temperature, and the stability of the intermediates was affected by the concentration of base used for the generation. The stability was also seen to be largely dependent on the electronic nature of porphyrin ligands, in which [(Porp)Mn^(V)=O]^(+) complexes bearing an electronrich porphyrin ligand were more stable than those bearing an electron-deficient porphyrin. Reactivity studies of the manganese(V)-oxo complexes revealed that the intermediates are capable of oxygenating PPh3 and thioanisoles but not olefins and alkanes, indicating that the [(Porp)Mn^(V)=O]^(+) is comparatively mild oxidant when composed to corresponding [(porp)Fe^(IV)=O] or [(porp)^(+)Fe^(IV)=O]^(+). The reactivity of [(Porp)Mn^(V)=O]^(+) complexes was enhanced significantly upon addition of acid, yielding oxygenated products in olefin epoxidation and alkane hydroxylation. The [(Porp)Mn^(V)=O]^(+) complexes associated with iodosylbenzene in the presence of base afforded high product yields in the oxygenation reactions under catalytic conditions. The latter results indicate that in addition to the manganese(V)-oxo species, there is at least one more active oxidant that effects the oxygenation reactions. Mechanistic aspects of the role of base and the oxygen atom transfer reactions are discussed in depth.;Cytochromes P450와 철-포르피린 착물에 의한 산소 전달 반응에서 여러 산화종이 관여되어 있는지에 대한 논의가 계속되고 있다. 여러 산화종이 존재한다는 이론의 주된 증거는 촉매, 산화제, 용매와 같은 반응 조건에 따라서 촉매 반응에서 얻어지는 반응 결과물이나 그 분포가 다름에 있었다. 이 연구에 있어서 다양한 반응조건에서 oxoiron(IV) porphyrin-cation radicals (1)을 직접 만들어서, 올레핀의 경쟁적인 에폭시화 반응, 알케인의 하이드록시화 반응, 올레핀의 C=C 에폭시화 반응과 알릴자리의 C-H 하이드록시화반응을 통하여 좀더 detailed 메커니즘 연구를 하였다. 결과 반응 결과물이나 그 분포는 반응 조건에 따라서 매우 달라짐을 알게 되었다. 예를 들어 다른 axial 리간드를 가진 1은 시스-, 트랜스-올레핀과 styrene과 para-치환된 styrene의 경쟁적인 에폭시화 반응에서 큰 반응 결과물의 선택성을 보였다 1에 의한 ethylbenzene의 하이드록시화반응에서는 axial 리간드와 기질에 따라서 1-phenylethanol and ethylbenzoquinone과 같은 다른 반응 결과물을 보였다. 또한 1에 의한 cyclohexene의 산화반응에서 C=C의 에폭시화 반응 대 C-H hydroxylation의 반응에서의 선택성은 반응 온도와 철 포르피린 착물의 전자의 특성, 그리고 기질에 따라서 매우 큰 차이를 보였다. 이러한 결과는 1이 다른 반응 조건에서 다양한 반응성의 경향성을 보여줌을 뜻하며, 따라서 철 포르피린 착물에 의한 촉매 산소화 반응에서의 다른 반응 결과물이나 분포가 여러 산화종이 있기 때문이 아니라, 다른 환경이기 때문에 1이 다른 결과를 나타남을 알 수 있었다. 이 연구는 1이 “chameleon oxidant” 와 같이 작용하여 환경의 변화에 의해서 반응성 및 선택성이 달라진다는 충분한 증거를 보여준다. 또 다른 High-Valent 메탈 옥소에 대한 연구는 상온에서 유기 용매에서 염기 조건에서 m-chloroperbenzoic acid, iodosylarenes, 그리고 H₂O₂와 같은 산화제를 사용하여 생성한 망간(V) 옥소 포르피린에 대한 것이다. 망간(V) 옥소 포르피린 착물은 UV-vis, EPR, electrospray ionization mass spectrometer, ¹H NMR, 그리고 resonance Raman spectroscopy와 같이 다양한 분광학적 방법으로 연구하였다. [(Porp)Mn^(V)=O]^(+) 종은 상온에서 안정하며 그 안정성은 반응 용액의 염기의 양과 리간드의 전자적 특성에 영향을 받음을 알 수 있었다. 그리고 [(Porp)Mn^(V)=O]^(+)은 PPh3과 thioanisole은 산화 시킬 수 있으나 올레핀이나 알케인과는 반응 않음으로써 산화력이 약함을 알 수 있었다. 그러나 산을 넣으면, 반응성이 매우 증가되어, 올레핀의 에폭시화반응과 알케인의 하이드록시화반응이 일어남을 확인 할 수 있었다. 또한 Iodosylbenzene과 [(Porp)Mn^(V)=O]^(+)종은 촉매반응에서 산화반응이 진행됨을 확인하였다. 이 결과는 망간(V) 옥소 종 이외에 적어도 하나 이상의 반응성 있는 산화종이 존재함을 뜻한다고 생각된다. 염기의 역할과 산소 전달 반응의 메커니즘에 대해서도 연구되었다.-
dc.description.tableofcontentsContents List of Figures = ⅳ List of Tables = ⅶ List of Abbreviations = ⅷ Part Ⅰ Oxoiron(Ⅳ) Porphyrin π-Cation Radical Complexes with a Chameleon Behavior in Cytochrome P450 Model Reactions = 1 Abstract = 2 Ⅰ. Introduction = 3 Ⅱ. Materials and methods = 5 Ⅱ-1. Materials = 5 Ⅱ-2. Instrumentation = 5 Ⅱ-3. Reaction Conditions = 6 Ⅱ-3-1. Competitive Olefin Epoxidations (Table 1) = 6 Ⅱ-3-2. Ethylbenzene Hydroxylation (Table 2) = 6 Ⅱ-3-3. Determination of KIE values (Table 3) = 7 Ⅱ-3-4. Oxygenation of Olefins (Tables 4 and 5) = 7 Ⅲ. Results and Discussion = 8 Ⅲ-1. Competitive Olefin Epoxidations Studied with Oxoiron (Ⅳ) Porphyrin π-Cation Radicals Bearing Different Axial Ligands = 8 Ⅲ-2. Oxoiron(IV) Porphyrin π-Cation Radicals Bearing Different Axial Ligands in Alkane Hydroxylation Reactions = 13 Ⅲ-3. Epoxidation versus Allylic Hydroxylation in Olefin Oxygenation by Oxoiron(Ⅳ) Porphyrin π-Cation Radicals = 17 Ⅳ. Conclusions = 25 Ⅴ. Reference = 26 Part Ⅱ Synthesis, Characterization, and Reactivity Studies of Manganese(V)-Oxo Porphyrin Complexes = 32 Abstract = 33 Ⅰ. Introduction = 34 Ⅱ. Materials and methods = 36 Ⅱ-1. Materials = 36 Ⅱ-2. Instrumentation = 36 Ⅱ-3. Reaction conditions = 37 Ⅱ-3-1. Preparation and Characterization of Manganese(V)-Oxo Complexes = 37 Ⅱ-3-2. Reactions of [(TDCPP)Mn^(V)=O]^(+) (1a) with Organic Substrates = 37 Ⅱ-3-3. Effect of Acid on the Reactivity of Manganese(V)-Oxo Porphyrins (Table 2) = 38 Ⅱ-3-4. Catalytic Oxygenation of Organic Substrates by 1a and PhIO (Table3)= 38 Ⅲ. Results and Discussion = 40 Ⅲ-1. Preparation and Characterization of Manganese(V)-Oxo Porphyrin Complexes = 41 Ⅲ-2. Effect of Base on the Stabilization of Manganese(V)-Oxo Porphyrins = 45 Ⅲ-3. Reactivity Studies of Manganese(V)-Oxo Porphyrins with Organic Substrates. = 46 Ⅲ-4. Effect of Acid on the Reactivity of Manganese(V)-Oxo Porphyrins = 51 Ⅲ-5. Catalytic Oxygenation of Olefins and Alkanes by Manganese(V)-Oxo Porphyrins and PhIO = 52 Ⅳ. Conclusions = 55 Ⅴ. Reference = 56 국문 초록 = 61-
dc.formatapplication/pdf-
dc.format.extent994406 bytes-
dc.languageeng-
dc.publisher이화여자대학교 대학원-
dc.titleHigh-Valent Metal-Oxo Porphyrins as Biomimetic Models for Oxidation Reactions-
dc.typeMaster's Thesis-
dc.creator.othername송윤주-
dc.format.pageⅷ, 64 p.-
dc.identifier.thesisdegreeMaster-
dc.identifier.major대학원 나노과학부-
dc.date.awarded2005. 8-
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