Browsing by Author "Du, Kun-Ju"

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Colorimetric sensing of Cu(II) by 2-methyl-3-[(pyridin-2-ylmethyl)-amino]-1,4-naphthoquinone: Cu(II) induced deprotonation of NH responsible for color changes
(2009)
Wu, Shu-Pao
;
Huang, Ray-Yui
;
Du, Kun-Ju
;
應用化學系
;
Department of Applied Chemistry
1,4-Naphthoquinone based chemosensors 1 and 2 detect only the presence of Cu(2+) ions among other transition metal ions by changing color from orange to dark blue. Chemosensors 1 and 2 function as tridentate ligands, which bind Cu(2+) ions through three functional groups: an amine nitrogen, a pyridine nitrogen and a quinone oxygen. On addition of Cu(2+), both 1 and 2 exhibit a 168 nm red shift in absorption wavelength (pH 7.0). The effect on pH by the formation of these Cu(2+) complexes was determined by UV-vis spectroscopic pH titration. In the pH range of 6-7.5, a maximum was observed at 634 nm and exhibited the formation of deprotonated 1-Cu(2+) and 2-Cu(2+) complexes. A reversible color change (orange-blue-orange) was observed when chemosensor 1 was mixed with Cu(2+) in CH(3)CN. This represents a reversible process of deprotonation and re-protonation of the 1-Cu(2+) complexes and also demonstrates the short half-life of thr deprotonated 1-Cu(2+) complexes in CH(3)CN.
Colorimetric sensing of Cu(II): Cu(II) induced deprotonation of an amide responsible for color changes
(2010)
Wu, Shu-Pao
;
Du, Kun-Ju
;
Sung, Yi-Ming
;
應用化學系
;
Department of Applied Chemistry
9,10-Anthraquinone-based chemosensor 1 indicates the presence of Cu(II) ions among other transition metal ions with high selectivity by a color change from yellow to dark red. Chemosensor 2 shows binding toward Cu(II), Ni(II) and Co(II) with color changes from yellow to dark red, red and pale green, respectively. Especially, Co(II) binding with chemosensor 2 causes significantly green fluorescence. On addition of Cu(II), 1 and 2 exhibit 76 and 80 nm red shifts in absorption wavelength (pH 7.0). The effect on pH by the formation of these 1-Cu(II) and 2-Cu(II) complexes was determined by UV-vis spectroscopic pH titration. In the pH range of 6-7.5, a maximum absorption was observed at 473 nm and exhibited the formation of deprotonated 1-Cu(II) and 2-Cu(II) complexes.