Molecular Recognition in Electron and Oxygen Transfer Reactions of Metal Complexes in Solid and in Solution

固体和溶液中金属配合物的电子和氧转移反应中的分子识别

• 批准号: 06640720
• 负责人: NAKAJIMA Kiyohiko
• 金额: $ 1.15万
• 依托单位: Aichi University of Education
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06640720/
• 关键词: Schiff base; Oxovanadium; Asymmetric; Electron transfer; Molecular recognition; Linear chain structure; Activation parameter; Kinetics

We have shown that the isomerization between the diastereomeric pair of an optically active Schiff base-oxovanadium (IV) complex is catalyzed by the oxidized oxovanadium (V) species. The electron-transfer reaction between the oxovanadium (IV) and oxovanadium (V) complexes was suggested to have an important role in the isomerization. Chiral Schiff base-oxovanadium (IV) complexes such as [VO {sal-(RR)-chxn}] (1) have been found to be enantioselective catalysts for the asymmetric oxidation of sulfides to sulfoxides. Accordingly, we studied the electron-transfer reaction between [VO {sal-(RR)-chxn}]Cl (2) and [VO{3-MeOsal-(RR) or (SS)-chxn}] (3-a or 3-b) which gives 1 and [VO {3-MeOsal-(RR) or (SS)-chxn}] Cl (4-a or 4-b) at equilibrium.The stereoselectivity of the reaction depends on temperature. For example, 3-b reacts 2.0 times faster than 3-a at 25ﾟC,while 1.6 times at 5ﾟC.The activation parameters were DELTAH<thermodynamics>_<RR-RR>=15.2(]SY.+-.])0.6kJ mol^<-1>, DELTAS(]SY.thermod.[)_< … More RR-RR>=-70.2(]SY.+-.])1.9 J mol^<-1> K^<-1>, DELTAH(]SY.thermod.[)_<SS-RR>=21.4(]SY.+-.])2.4kJ mol^<-1>, and DELTAS(]SY.thermod.[)_<SS-RR>=-43.7(]SY.+-.])8.1 J mol^<-1> K^<-1>.Although we do not have any conclusive evidence which determines that the present reaction proceeds by the inner-sphere mechanism, the two reacting vanadium atoms must be brought sufficiently close together when the electron-transfer occurs. It should be reasonable that the oxo ligand of oxovanadium (IV) complex interacts at the position trans to the oxo ligand of the oxovanadium (V) complex because the latter prefers a six-coordinate structure. The dinuclear structure of [(salen)V^<IV>OV^VO (salen)]I_5・CH_3CN (H_2salen=N,N'-disalicyl-idene-1,2-ethanediamine) was reported, which has a V^<IV>=O・・・V^V=O bond. A similar dinuclear structure may be expected for the intermediate of the electron-transfer reaction. The chiral recognition must be due to the difference in the non-bonding steric interaction between the ligands in the two intermediate structures. Less

我们已经表明，光学活性的席夫碱-氧钒（IV）配合物的非对映异构体之间的异构化是由氧化的氧钒（V）物种催化。钒氧（IV）和钒氧（V）配合物之间的电子转移反应被认为在异构化反应中起重要作用。手性Schiff碱-钒氧配合物[VO {sal-（RR）-chxn}]（1）是一种对映选择性催化剂，可催化硫化物不对称氧化为亚砜。因此，我们研究了[VO {sal-（RR）-chxn}]Cl（2）与[VO{3-MeOsal-（RR）或（SS）-chxn}]（3-a或3-B）之间的平衡电子转移反应，得到1和[VO {3-MeOsal-（RR）或（SS）-chxn}] Cl（4-a或4-B）。例如，3-B在25 ℃时的反应速度是3-a的2.0倍，而在5 ℃时的反应速度是3-a的1.6倍<thermodynamics><RR-RR>。0.6kJ mol^<-1>，DELTAS（]SY.thermod. [)_< ...更多信息 RR-RR&gt;=-70.2（]SY.+-.]）1.9 J mol^<-1>K^<-1>，Δ H（]SY.thermod. [）_<SS-RR>=21.4（]SY.+-.]）2.4kJ mol ~<-1>（-1）和DELTAS（]SY.thermod. [）_<SS-RR>=-43.7（]SY.+-.]）8.1虽然<-1><-1>我们没有任何决定性的证据来确定本反应是通过内层机制进行的，但是当电子转移发生时，两个反应的钒原子必须足够靠近。氧钒（IV）配合物的氧代配体在氧钒（V）配合物的氧代配体的反式位置处相互作用应该是合理的，因为后者优选六配位结构。报道了[（salen）V^<IV>OV^VO（salen）]I_5·CH_3CN（H_2salen=N，N '-二异丙基-1，2-乙二胺）的双核结构，其中V^<IV>=O···V^=O键。电子转移反应的中间体可能具有类似的双核结构。这种手性识别是由于两种中间结构中配体之间的非键空间相互作用的差异。少

项目成果

M.Hirotsu: "Steric Control of Redox Potentials of Cobalt(II) Schiff Base Complexes with Phenyl Substituents" Chem.Lett.,. 1994. 2183-2186 (1994)

M.Hirotsu：“具有苯基取代基的钴(II)席夫碱配合物氧化还原电位的空间控制”Chem.Lett.,。

M.Hirotsu: "Manganese (III) Complexes Containing Opyically Active Tetradentate Schiff Base Ligands. Effect of Phenyl Substituents" Inorg.Chem.,. 34. 6173-6178 (1995)

M.Hirotsu：“含有光学活性四齿席夫碱配体的锰 (III) 配合物。苯基取代基的影响”Inorg.Chem.,。

M.Hirotsu, K.Nakajima, M.Kojima, and Y.Yoshikawa: "Manganese (III) Complexes Containing Optically Active Tetradentate Schiff Base Ligands. Effect of Phenyl Substituents" Inorg. Chem.34. 6173-6178 (1995)

M.Hirotsu、K.Nakajima、M.Kojima 和 Y.Yoshikawa：“含有光学活性四齿希夫碱配体的锰 (III) 配合物。苯基取代基的影响”Inorg。

K.Nakajima: "Isomerization of a Diastereomeric Oxovanadium(IV) Complex Containing an Unsymmetrical Tetradentate Schiff Base Ligand Catalyzed by their Oxovanadium(V) Species" Chem. Lett.,. 1994. 1593-1596 (1994)

K.Nakajima：“含有不对称四齿席夫碱配体的非对映体氧钒（IV）络合物的异构化由其氧钒（V）物种催化”Chem。

M.Hirotsu: "Steric Control of Redox Potentials of Cobalt(II)Schiff Base Complexes with Phynyl Substituents" Chem. Lett.,. 1994. 2183-2186 (1994)

M.Hirotsu：“具有苯基取代基的钴(II)席夫碱配合物的氧化还原电位的空间控制”Chem。