二價銅離子化學偵測分子之開發及評估

Abstract

這個計畫主要是設計二價銅離子化學偵測分子，分別以胜肽(peptide)及萘酚醌 (naphthoquinone) 為主，用以偵測二價銅離子。以胜肽為主的化學偵測分子，使用的胜 肽為GG、GGG、GH、GGH、HG、HGG、HGH、HGGG 及HGHGH，並連接發色團或 螢光團。所使用發色團為2, 4-dinitroaniline，螢光團為dansyl amine 和fluorescein。另 一類化學偵測分子是以萘酚醌(naphthoquinone)為主，並接上各種金屬螯合基。過渡金屬 離子VO2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+ 及Zn2+，用來測試所設計化學偵測分子對這些離 子的反應。對於連接發色團的分子，二價銅離子鍵結將使顏色改變；對於連接螢光團的 分子，二價銅離子鍵結將使螢光減弱。所設計化學偵測分子對二價銅離子的靈敏度 (sensitivity)及pH 的影響，亦是研究的重點。

In this proposal, we design two series of Cu2+ chemosensors based on peptide (part A) and naphthoquinone (part B). In Part A, peptides such as GG, GGG, GH, GGH, HG, HGG, HGH, HGGG, HGHGH are used as Cu2+ binding motifs. Each peptide is connected with a chromophore (2, 4-dinitroaniline) or two fluorophores (dansyl amine and fluorescein). The selectivity of each chemosensor is evaluated by UV-Vis and fluorescence spectra. Several transition metal ions, such as VO2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+ and Zn2+ are used in evaluation of metal ion selectivity. The pH effect on metal ion binding is also discussed in studies. In Part B, 2-methyl-1,4-naphtho-quinone is used as a chromogenic center. The molecules are designed by linkage of 2-methyl-1,4-naphthoquinone with metal-binding ligands. Bidentate, tridentate and tetradentate ligands are used as Cu2+ binding motifs. Cu2+ binding within ligands makes Cu2+ close enough to form a bond or interact with the oxygen atom in naphthoquinone and results in a significant red shift. Transition metal ions, such as Zn2+, Cu2+, Ni2+, Co2+, Fe2+, Fe3+, Mn2+, VO2+ are used in binding study.