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| 題名: | N,N,O-蠍狀三牙基配位銅錯合物合成及C−H鍵活化反應研究;Synthesis and Characterization of Copper N,N,O-Scorpionate Complexes and Study of C−H Activation |
| 作者: | 李佳珊;Li,Jia-shan |
| 貢獻者: | 化學學系 |
| 關鍵詞: | 蠍狀配位子;C−H 鍵活化;銅金屬蛋白;Scorpionate ligand;C−H activation;copper-containing protein |
| 日期: | 2014-08-14 |
| 上傳時間: | 2014-10-15 14:39:03 (UTC+8) |
| 出版者: | 國立中央大學 |
| 摘要: | 為了模擬銅金屬蛋白活性中心的結構與功能，本研究合成具有N,N,O配位能力的異蠍狀三牙基配位子Lithium 2,2-bis(3,5-di-tert-butylpyrazol-1-yl)acetate Li(bdtbpza) (3)。使用pyrazole來模擬組胺酸(Histidine)的imidazole，且在環上加上取代基異丁基(tert-butyl)藉此模擬生物蛋白鍊的龐大立體障礙。配位子Li(bdtbpza) (3)與二價銅金屬鹽類Cu(NO3)2．2.5H2O進行錯合反應，依長晶溫度不同可得到單核銅錯合物[CuII(bdtbpza)(NO3)] (4)及雙核銅錯合物[CuII2(bdtbpza)2(NO3)2] (5)。將錯合物(4)加入還原劑鋅汞齊於不同溶劑中可得到錯合物[ZnII2(bdtbpza)2(NO3)2] (6)與[CuI3(bdtbpza)3ZnII(NO3)2] (7)，另外以一價銅金屬鹽類[Cu(CH3CN)4](PF6)與Li(bdtbpza) (3)反應可直接合成一價銅錯合物[CuI3Li(bdtbpza)3(MeOH)](PF6) (8)。
本論文以模擬銅的氧合酵素為主要研究，將錯合物(4)進行還原反應後形成的一價銅錯合物、錯合物(7)及(8)進行C−H 鍵活化及氧合反應，皆可得到相同的產物[Cu2II(bdtbpzaO)2] (9)。以錯合物(8)為起始物進行氧合反應除了得到錯合物(9)外，也得到新的氧合反應產物[CuII(bdtbpzaOH)(DMF)](PF6) (10)。利用UV-Vis吸收光譜及ESI-Mass光譜追蹤C−H 鍵活化的反應過程。室溫UV-Vis光譜追蹤中，錯合物(4)的d−d transition的吸收度隨時間的增加而增強，且波長逐漸往高能量方向移動﹔錯合物(8)於室溫(30 oC)ESI-MS光譜追蹤其離子峰m/z = 599.3推測是反應中間物雙核CuII−peroxide。而低溫(−55 oC)的UV-Vis光譜追蹤於357 nm生成的吸收峰推測可能是來自於CuII−superoxide或是CuII−peroxide的吸收，亦可能是產物錯合物(9)與(10)的吸收。將C−H 鍵活化及氧合反應得到的產物錯合物(9)，進行去金屬化反應可得[Na2(bdtbpzaO)2] (11)，可作為其他雙核金屬錯合物的起始物。
;In order to mimic the active site structure and function of copper proteins, the N,N,O-hetroscorpionate ligand, Lithium 2,2-bis(3,5-di-tert-butylpyrazol-1-yl)acetate (3) has been synthesized. Pyrazole rings of ligand were used to mimic imidazole of histidine. A sterically constrained group like tert-butyl group is added to each pyrazole rings that in order to mimic the bulky protein peptide chains. Treatment of ligand Li(bdtbpza) (3) with divalent cupric salt, Cu(NO3)2．2.5H2O, resulted in the formation of two complexes [CuII(bdtbpza)(NO3)] (4) and [CuII2(bdtbpza)2(NO3)2] (5). The conversion between complexes (4) and (5) is temperature-dependent. Complex (4) was achieved at ambient temperature while complex (5) was obtained at low temperature (< −20 oC). The reaction of complex (4) and zinc amalgam in different solvents led to different structures i.e. [ZnII2(bdtbpza)2(NO3)2] (6) from DMF and [CuI3(bdtbpza)3ZnII(NO3)2] (7) from THF. On the other hand, copper(I) complex [CuI3Li(bdtbpza)3(MeOH)](PF6) (8) was synthesized by using [Cu(CH3CN)4](PF6) as the starting metal source.
To study copper oxygenases, reduction of complex (4) or (5) and further conducting with O2(g) process C−H activation and oxygenation to [Cu2II(bdtbpzaO)2] (9), which was also got from a reaction of CuI-containing complex (7) or (8) with O2(g). Interestingly, the reaction of complex (8) and O2(g) not only achieved the dimeric product, (9), but isolated another monomeric product, [CuII(bdtbpzaOH)(DMF)](PF6) (10) was. The activation process is monitored by UV-Vis spectra and ESI-Mass spectra. In the activation of complex (4) at ambient temperature, the time-course UV-Vis showed the absorbance of d−d transition increasing with lengthening time, and the wavelength shifted to higher energy gradually. In the time-course UVVis spectra at −55 oC, the activation of complex (8) exhibited an increasing intensity of the absorption band at 357 and 659 nm. This absorption spectrum was similar to that of complex (9); therefore, it cannot be absolutely assigned as the result from neat CuII−superoxide, CuII−peroxide, complex (9) or (10). In the experiment of tracking ESI-Mass, the fragement, m/z = 599.3, was considered to be copper(II)peroxide. The demetallation of the product (9) from CH activation gave a new ligand, [Na2(bdtbpzaO)2] (11), which allows us to extent another new model chemistry. |
| 顯示於類別: | [化學研究所] 博碩士論文
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