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  • 學位論文

亞硝基錳硫化合物:電子順磁光譜、超導量子干涉儀、及單晶繞射儀之物理性質研究

Anionic/Dianionic Manganese-Thiolate Nitrosyl Complexes Characterized by EPR, SQUID, and Single-Crystal X-ray Diffraction

指導教授 : 廖文峰
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摘要


將溶在MeOH的[Na]2[S,S-C6H3-R] 加入MnBr2和[PPN][Cl] (或是[Et4N][Br])的THF溶液中,即可合成出化合物 [(THF)Mn(S,S-C6H3-R)2] – (R = H (1a), Me (1b); thf = C4H8O),並根據電子順磁共振儀(Electron paramagnetic resonance,EPR)以及超導量子干涉磁量儀(Superconducting quantum interference device,SQUID)的結果說明化合物1a/1b的電子組態為High spin的d4型態。化合物1a/1b在CH2Cl2溶劑下會轉變為[Mn(S,S-C6H3-R)2]22- (R = H (2a), Me (2b)),根據EPR與SQUID的結果說明化合物2a/2b的電子組態為High spin的d4型態。 藉由還原劑[PPN][BH4]或[Et4N][BH4]將化合物2a/2b還原為 [Mn- (S,S-C6H3-R)2]2- (R = H (3a), Me (3b)),化合物3a/3b相當的空氣敏感,並且其電子組態為High spin的d5型態。藉由比較化合物1、2、3的金屬-配位基距離,可以知道當金屬氧化態越高時,造成金屬與配位基之間的距離縮短。化合物3a/3b在CH2Cl2或CH3CN溶劑下氧化後會同時形成化合物2a/2b與化合物 [Mn (S,S-C6 H3-R)3]22- (R = H (6a), Me (6b))的產物;在THF溶劑下氧化後則會形成化合物1a/1b。 將化合物2a/2b或3a/3b與NO反應後,分別生成 [(NO)Mn(S,S -C6H3-R)2] – (R = H (4a), Me (4b))與 [(NO)Mn(S,S-C6H3-R)2] 2- (R = H (5a), Me (5b))根據X-ray、IR、EPR與SQUID儀器的測量推測化合物4a/4b的電子組態為{Mn(NO)}5並且有{MnIII(NO•)}5與{Mn II(NO+)}5兩種狀況存在;化合物5a/5b的電子組態為{Mn(NO)}6並且也具有{MnIII(NO–)}6與{MnII(NO•)}6的共振性存在。在化合物4a/4b加入[PPN][S,NH2-C6H4]後會轉變為化合物5a/5b,並且其IR的吸收位置由1727(KBr)cm-1(4b)轉變成1650(KBr)cm-1(5b),這說明在還原過程中電子添加在NO的反鍵結(π-antibnding)軌域上而造成IR訊號大幅降低。將化合物5a/5b接觸氧氣後會生成化合物4a/4b與6a/6b,化合物6a/6b其電子組態為High spin的d3型態。

並列摘要


The anionic mononuclear Mn-thiolate complexes [(thf)Mn(S,S-C6H3-R)2]– (R = H (1a), Me (1b) was assigned as a high spin d4 (Mn(III)) electronic structure based on EPR and SQUID analysis. Presumably, the role of tetrahydrofuran ligand coordinated to the Mn(III) center in complexes 1a/1b is to reimburse the electron deficiency of the Mn(III) center as well as to stabilize the Mn(III) oxidation level. The conversion of complexes 1a/1b to the stable dimeric [Mn(S,S-C6H3-R)2]2 2– (R = H (2a), Me (2b)) was displayed when CH2Cl2 solvent was added into complexes 1a and 1b at ambient temperature. Formation of complexes 2a/2b can be interpreted as coordinative association of two anionic mononuclear [Mn(S,S-C6H3-R)2]– in the absence of thf coordinating solvent. The electronic configuration of complexes 2a/2b was assigned as high spin d4 Mn(III) in a square pyramidal ligand field. Complex 2a/2b was reduced by [PPN][BH4] (or [Et4N][BH4]) to yield [Mn(S,S-C6H3-R)2] 2– (R = H (3a), Me (3b)). The electronic configuration of complexes 3a/3b was assigned as high spin d5 Mn(II) in a tetrahedral ligand field. Reaction of complexes 2a/2b and NO(g) afforded a discrete mononitrosyl-manganese [(NO)Mn(S,S-C6H3-R)2]– (R = H (4a), Me (4b)) assigned as the resonance hybrid of {MnIII-NO˙} and {MnII-NO+} electronic configuration in a square pyramidal ligand field. Complexes 3a/3b was nitrosylated to produce [(NO)Mn(S,S-C6H3-R)2] 2– (R = H (5a), Me (5b)). The {Mn(NO)}6 5a/5b was best described as the resonance hybrid of {MnIII-NO–} and {MnII-NO˙} electronic configuration in a square pyramidal ligand field. The complexes 5a/5b was oxidized to yield [Mn(S,S-C6H3-R)3] 2– (R = H (6a), Me (6b)). The electronic configuration of complexes 6a/6b was assigned as high spin d3 Mn(IV) in a distorted octahedral ligand field.

並列關鍵字

Manganese Nitrosyl Complexes EPR SQUID X-ray Nitric oxide

參考文獻


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