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ルテニウム（II）ヒピリジン錯体による二酸化炭素の活性化に関する研究
https://ir.soken.ac.jp/records/146
https://ir.soken.ac.jp/records/1461d169081-f497-4db7-bff8-c1b8b510b273
| 名前 / ファイル | ライセンス | アクション |
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要旨・審査要旨 / Abstract, Screening Result (297.1 kB)
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本文 (1.4 MB)
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| Item type | 学位論文 / Thesis or Dissertation(1) | |||||
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| 公開日 | 2010-02-22 | |||||
| タイトル | ||||||
| タイトル | ルテニウム（II）ヒピリジン錯体による二酸化炭素の活性化に関する研究 | |||||
| タイトル | ||||||
| タイトル | Mechanistic Investigation of CO2Activation on Ruthenium(II)Bipyridine Complexes | |||||
| 言語 | en | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_46ec | |||||
| 資源タイプ | thesis | |||||
| 著者名 |
田中, 聡明
× 田中, 聡明 |
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| フリガナ |
タナカ, ヒロアキ
× タナカ, ヒロアキ |
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| 著者 |
TANAKA, Hiroaki
× TANAKA, Hiroaki |
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| 学位授与機関 | ||||||
| 学位授与機関名 | 総合研究大学院大学 | |||||
| 学位名 | ||||||
| 学位名 | 博士（理学） | |||||
| 学位記番号 | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | 総研大甲第44号 | |||||
| 研究科 | ||||||
| 値 | 数物科学研究科 | |||||
| 専攻 | ||||||
| 値 | 07 構造分子科学専攻 | |||||
| 学位授与年月日 | ||||||
| 学位授与年月日 | 1993-03-23 | |||||
| 学位授与年度 | ||||||
| 値 | 1992 | |||||
| 要旨 | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | Utilization of CO2 under mild conditions is interesting in the viewpoints of predictable energy shortage in near future and the increase in the concentration of CO2 in the atmosphere. Photo-and electrochemical CO2 reductions using homogeneous catalysts have been intensively studied, and several reaction mechanisms have been proposed so far. None of them, however, is generally accepted due to the lack of the evidence concerning the structural changes in the conversion from CO2 to CO on metal atoms. Such the fundamental problem, therefore, may be provided the elucidation of the boning characters between CO2 and metal complexes of the reaction intermediates, and the relative nucleophilicities of CO2 and proton toward metal centers in protic media. The purpose of the present work is to give some insight into the reaction mechanism of the electro-and photochemical CO2 reduction catalyzed by metal complexes. To clarify the acidity of CO ligated on metal complexes may give fundamental information on the conversion of CO2 to CO. It is reported that not only CO but also NO ligated on some metals reversibly react with OH- to form M-XO2 and M-X(O)OH complexes (X=C, N) in H2O. The acidity of those ligands, however, has not been directly compared with each other under the same conditions, so far. In the Chapter II, [Ru(NO2)(CO)(bpy)2]PF6 (bpy=2.2'-bipyridine) was prepared by a reaction of [RuCl(CO)(bpy)2]PF6 with NaNO2 in order to elucidate the acidic and basic characters of CO and NO2- ligands on Ru. X-Ray structural analysis of [Ru(NO2)(CO)(bpy)2]PF6 reveals that CO and NO2 ligands on Ru(II) are in a cis-position. The Ru-N (bpy ligands) bond distances (trans to CO and NO2-) are 2.10(1) and 2.11(1) Å, respectively, and the remaining two Ru-N bond distances (trans to bpy ligands) are 2.07(1) and 2.08(1) Å. Thus, any distinct differences between CO and NO2- ligands were not observed from the Ru-N bond distances. Treatment of [Ru(NO2)(CO)(bpy)2]+ with HCI resulted in the formation of [RuCl(CO)(bpy)2]+, and a reaction product of [Ru(NO2)(CO)(bpy)2]+with H2SO4 showed v(C=O) and v(N=O) at 1968 and 1911 cm-1 , respectively. On the other hand, [Ru(NO2)(CO)(bpy)2]+ reversibly reacts with Bu4NOH to afford [Ru(C(O)OH) (NO2)(bpy)2] in CH3CN. These results indicate that the acidity of a carbonyl ligand is weaker than a nitrosyl one. Among a variety of CO2 metal complexes, η1 (C)-CO2 metal complexes are genterally believed to be plausible intermediates in the electrochemical CO2 reduction affording CO. In the Chapter III, the molecular structures of [Ru(CO)2(bpy)2](PF6)2, [Ru(C(O)OCH3)(CO)(bpy)2]BPh4.CH3CN as model of [Ru(C(O)OH)(CO)(bpy)2]+ , and [Ru(η1 (C)-CO2)(CO)(bpy)2]･3H2O were described. The latter two were prepared by the reactions of [RU(CO)2(bpy)2]2+ with CH3ONa and two equiv of OH-. On the basis of the fact that the Ru-C(O)OCH3 bond distance of [Ru(C(O)OCH3)(CO)(bpy)2]+ is shorter than the Ru-CO2 one of [Ru(η1(C)-CO2)(CO)(bpy)2], a multi-bond character of the RU-CO2 bond is not larger than that of the Ru-C(O)OCH3 bond. One extra electron pair iuvolved in [Ru(η1(C)-CO2)(CO)(bpy)2 resulting from dissociation of the terminal proton of [Ru(C(O)OH)(CO)(bpy)2]+ may, therefore, localize mainly in the CO2 ligand. The inclrease in the electron density of the CO2 moiety is effectively compensated by the extended three-dimensional network of hydrogen boundings between the CO2 ligand and three water molecules of [Ru(η1 (C)-CO2)(CO)(bpy)2].3H2O. Smooth conversion of [Ru(η1 (C)-CO2)(CO)(bpy)2] to[Ru(C(O)OH)(CO)(bpy)2]+ is the one of the key reactions in the catalytic cycle of the CO2 reduction by [Ru(CO)2(bpy)2]2+. In the Chapter IV, the reactivity of [Ru(η1 (C)-CO2)(CO)(bpy)2] was examined to elucidate the basicity of the CO2 moiety. All the oxygen atoms of [Ru(η1 (C)-CO2)(CO)(bpy)2] undergo an exchange reaction by H218O. The reactions of [Ru(η1 (C)-CO2)(CO)(bpy)2] with CH3l and 1CH2CH2l gave [Ru(C(O)OCH3)(CO)(bpy)2]+ and [Rul(CO)(bpy)2]+ in quantitative yields. AC-H bond of organic molecules with active hydrogen such as malouic acid derivatives was also cleaved by the CO2 moiety of [Ru(η1 (C)-CO2)(CO)(bpy)2]. There still remains a matter of controversy about the initial step of the CO2 reduction catalyzed by metal complexes, which of proton or CO2 initially attacks on low valent metal centers. In the Chapter V, interaction between CO2 and reduced quinones is examined in CH3CN, CH3CN/H2.O, and CH3OH to evaluate the nucleophilicity of CO2 in protic media. Carboxylation predominantly took place on the oxygen atoms of 2,3,5,6-tetramethyl-1,4-benzoquinone dianion in CO2- saturated CH3OH and CH3CN/H2O (9:1 v/v). This result implies the formation of M-CO2 bond rather than that of M-H one in catalytic cycles in photo-and electrochemical CO2 reduction catalyzed by transition metal complexes. |
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| 値 | 有 | |||||
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| 内容記述タイプ | Other | |||||
| 内容記述 | application/pdf | |||||
