- 學位論文
軸位配基可置換之三角雙錐三價銅錯合物的電子結構及反應特性
Electronic Structure and Reactivity of Trigonal Bipyramidal Copper(III) Complexes with an Exchangeable Axial Ligand
若您是本文的作者，可授權文章由華藝線上圖書館中協助推廣。
摘要
本研究承繼實驗室先前的工作，合成出三角雙錐構形的三價銅錯合物[PPN][Cu(TMSPS3)(Cl)] (錯合物1)。根據製備條件與錯合物1產率的關係以及DFT理論計算的結果，推測錯合物1和一同生成的一價銅副產物，是經由TMSPS3–Cu2Cl4中間體，進行熱力學驅動之二價銅自身氧化還原反應而產生。藉UV–vis光譜監測錯合物1與外加配基的滴定，結果符合配位基與氯離子的1:1置換平衡反應，而不同配位基之相對結合常數為：N3− (Keq = 18)、DABCO (8)、pyridine (0.13)、2,6-lutidine (0.0010)，此結果也解釋了錯合物1在溶液中的半穩定性質。據此進而合成了軸位配基衍生之錯合物：[PPN][Cu(TMSPS3)(N3)] (錯合物2)、[Cu(TMSPS3)(DABCO)] (錯合物3)和[PPN][Cu(TMSPS3)(NCS/Cl)] (錯合物4/1)。量測錯合物1–3之銅和硫元素的X-ray K-edge吸收光譜，可證實：銅離子的正三價氧化態、三角雙錐配位場造成錯合物LUMO(3dz2貢獻)的抬升、及銅—硫之間的高度共價性。這些結果指出Cu(TMSPS3)配位基團內的電子密度補償效應 (S→Cu)，一方面穩定了中心的三價銅離子，一方面也削弱了其軸位配基結合對靜電作用的需求。氰根配位的衍生物 [PPN][Cu(TMSPS3)(CN)] (錯合物5) 是由錯合物1和NaOH於CH3CN中反應而得；並藉NMR、UV–vis、IR等光譜跡象歸結：應有cyanomethide配位的三價銅中間體存在，從而引發CH3CN溶劑的C–CN鍵斷裂。此外，Sc(OTf)3會將錯合物1所配位的氯離子拔除，使三價銅片段裸露並導致二聚體[Cu(TMSPS3)]2 (錯合物6) 的形成。以上結果有助於未來高價銅催化劑的開發。
並列摘要
A trigonal bipyramidal copper(III) complex, [PPN][Cu(TMSPS3)(Cl)] (complex 1), was synthesized following our previous studies. Basing on the correlation between yields and preparation conditions as well as DFT calculations, we propose a thermodynamically favored copper(II) disproportionation occurs within a TMSPS3–Cu2Cl4 intermediate, producing complex 1 and a copper(I) side-product. UV–vis titrations of complex 1 with various additive ligands, such as N3− (Keq = 18), DABCO (8), pyridine (0.13) and 2,6-lutidine (0.0010), comply 1:1 ligand–chloride exchange in solution, hence clarifying the semi-stability of complex 1 in solution phase. Derivatized [PPN][Cu(TMSPS3)(N3)] (complex 2), [Cu(TMSPS3)(DABCO)] (complex 3) and [PPN][Cu(TMSPS3)(NCS/Cl)] (complex 4/1) were then accordingly synthesized. Cu and S K-edge X-ray absorption spectra of complexes 1–3 reveal the elevated LUMO (3dz2 feathered) in TBP ligand field with their +3 oxidation state of copper and the Cu–thiolate covalency. These indicate the electron density compensation (S→Cu) within Cu(TMSPS3) moiety, which not only stabilizes copper(III) center but also supresses the electrostatic demand for the axial ligand binding. A cyano derivative, [PPN][Cu(TMSPS3)(CN)] (complex 5), was isolated from the reaction of complex 1 with NaOH in CH3CN; and a cyanomethide-bound copper(III) intermediate is evidenced by NMR, UV–vis, and IR spectra, responsible for the C–CN bond cleavage of CH3CN solvent. Additionally, chloride of complex 1 is abstracted by Sc(OTf)3, which exposes the copper(III) moiety and leads the formation of dimeric [Cu(TMSPS3)]2 (complex 6). These results facilitate further development of high-valent copper catalysts.
參考文獻
1. David L. Nelson, Michael. M. Cox Lehninger Principles of Biochemistry, 6/ed; W. H. Freeman & Company: New York, 2012; pp 158–172.
2. John. T. Groves, Robert C. Haushalter, Mikio Nakamura, Thomas E. Nemo, B. J. Evans J. Am. Chem. Soc. 1981, 103, 2884–2886.
3. James E. Penner-Hahn, Kim Smith Eble, Thomas J. McMurry, Mark Renner, Alan L. Balch, John T. Groves, John H. Dawson, Keith O. Hodgson J. Am. Chem. Soc. 1986, 108, 7819–7825.
4.(a) Hans-Petter Hersleth, Ulf Ryde, Patrik Rydberg, Carl Henrik Görbitz, K. Kristoffer Andersson J. Inorg. Biochem. 2006, 100, 460–476. (b) Jonathan Rittle, Michael T. Green Science 2003, 299, 1037–1039.
5. Johannes Hohenberger, Kallol Ray, Karsten Meyer Nat. Commun. 2012, 3, No. 720.