title: Dipyrrolylquinoxaline-bridged Schiff bases: a new class of fluorescent sensors for mercury(II).
abstract: Novel 2,3-bis(1H-pyrrol-2-yl)quinoxaline-functionalized Schiff bases were prepared and characterized as new fluorescent sensors for mercury(II) ion. The X-ray crystal structures of compounds 4, 5, 4a and 5a were determined. The binding properties of 4 and 5 for cations were examined by UV-vis and fluorescence spectroscopy. The UV-vis and fluorescence data indicate that a 1 : 1 stoichiometric complex is formed between compound 4 (or 5) and mercury(II) ion, and the association constant is (3.81 +/- 0.7) x 10(5) M(-1) for 4 and (3.43 +/- 0.53) x 10(5) M(-1) for 5. The recognition mechanism between compound 4 (or 5) and metal ion was discussed based on their chemical construction and the fluorescence quenching effect when they interact with each other. Competition experiments revealed that compound 4 (or 5) has a highly selective response to mercury(II) ion in aqueous solution.
authors.affiliation: Department of Chemistry, Wuhan University, Wuhan, Hubei, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Xun-Jin
authors.initials: XJ
authors.lastname: Zhu
authors.forename: Wai-Yeung
authors.initials: WY
authors.lastname: Wong
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Guo
authors.forename: Wai-Kwok
authors.initials: WK
authors.lastname: Wong
authors.forename: Zao-Ying
authors.initials: ZY
authors.lastname: Li