含氮氧多牙基之銅錯合物的合成、結構、催化反應與槲黃素氧化酶活性中心模擬之研究

Abstract

為了合成槲黃素氧化酶金屬活性中心的擬態化合物，本研究合成一含雙吡啶胺多牙基配子2,6-bis(3-bis(2-pyridinylmethyl)- aminopropanamide)toluene (BBPAT)，由此配子成功地合成出兩個二價銅錯合物[Cu2(BBPAT)](ClO4)4•2H2O (1)和[Cu2(BBPAT)(CH3OH)2]- (CF3SO3)4 (2)，並利用元素分析、紅外光和紫外光/可見光光譜儀及X-光結構解析法完成錯合物的鑑定。 由紅外光光譜可發現錯合物1在液態及固態時的光譜略有差異，在固態光譜中，於1657 cm-1有ㄧ個醯胺的C=O吸收峰，而在液態光譜中此吸收峰卻移動到了1676 cm-1，且配子的C=O吸收峰在1672 cm-1的位置，與錯合物醯胺的C=O吸收峰相當接近。故推測當錯合物在溶液狀態時，與銅離子鍵結的C=O，有可能被溶劑分子所取代，如此，將使受質(3-hydroxyflavone)有更多空間可與銅離子配位，以便於進行催化反應。 最後，將受質3-hydroxyflavone溶於二甲基甲醯胺中，加熱溶液至120 ºC並加入氧氣，接著將錯合物2 (5 mol %) 加入反應溶液中進行氧化反應，反應24小時後。經由管柱層析法及GC/MS將混合物分離鑑定得到產物為3-(dimethylamino)-3-phenyl-3H-chromene- 2,4-dione，2-(dimethylamino)-2-phenylbenzofuran-3(2H)-one，benzoic acid，N,N’-dimethylbenzamide以及2-hydroxybenzil。A polydentate ligand with two symmetric side arms, 2,6-bis(3-bis- (2-pyridinylmethyl)aminopropanamide)toluene (BBPAT), was prepared to construct mimics for the active site of the quercetin 2,3-dioxygenase (2,3-QD). Two copper(II) complexes, [Cu2(BBPAT)](ClO4)4 (1) and [Cu2(BBPAT)(CH3OH)2](CF3SO3)4 (2), were synthesized and characterized by elemental analysis, IR and UV/Vis spectroscopies, and X-ray crystallography. One absorption band at 1657 cm-1, corresponding to the carbonyl groups of amide of BBPAT, was observed in the solid IR spectrum (KBr) of complex 1. Interestingly, the absorption band was shifted to 1676 cm-1, close to that of free ligand at 1672 cm-1, as the IR spectrum of 1 was performed in CH3CN. We suspected that the carbonyl groups of BBPAT was dissociated from the copper centers, and the resulting open site of each copper was occupied by a solvent molecule. Once the substrate, 3-hydroxyflavone, was added to the solution of complexes 1 and 2, the coordinated solvent molecules were substituted by the substrate. After the dry DMF solution of 3-hydroxyflavone was heated to 120 °C and bubbled with dioxygen, complex 2 (5 mol %) was added to the DMF solution. The reaction mixture were kept at 120 ºC and stirred for 24 hours, and the resulting solution was separated by column chromatography. Five products, 3-(dimethylamino)-3-phenyl-3H- chromene-2,4-dione, 2-(dimethylamino)-2-phenylbenzofuran-3(2H)-one, benzoic acid, N,N’-dimethylbenzamide and 2-hydroxybenzil were isolated and analyzed by GC/MS spectroscopy.