Jisha Vadakkancheril S, Thomas Anu J, Ramaiah Danaboyina
Photosciences and Photonics, Chemical Sciences and Technology Division National Institute for Interdisciplinary Science and Technology (NIIST) CSIR, Trivandrum 695 019, India.
J Org Chem. 2009 Sep 4;74(17):6667-73. doi: 10.1021/jo901164w.
Chimeric dyads 1a and 1b based on dansyl and naphthalimide units linked through the polymethylene group were synthesized, and their photophysical and interactions with various metal ions were investigated under different conditions. These dyads showed dual emission centered at around 375 and 525 nm, respectively, due to the locally excited state of the naphthalimide chromophore and energy-transfer-mediated emission (FRET) from the dansyl moiety. When titrated with various metal ions, these systems exhibited unusual selectivity for Cu(2+) ions as compared to Na(+), Li(+), K(+), Zn(2+), Pb(2+), Hg(2+), Co(2+), Fe(2+), Cd(2+), Mg(2+), and Ba(2+) ions and signaled the binding event through inhibition of FRET mediated emission at 525 nm with concurrent enhancement in the emission intensity of the naphthalimide chromophore at 375 nm. The uniqueness of these dyads is that they form stable 2:1 stoichiometric complexes involving sulfonamide functionality and act as visual fluorescence ratiometric probes for the selective recognition of Cu(2+) ions.
合成了基于通过亚甲基连接的丹磺酰基和萘二甲酰亚胺单元的嵌合二元化合物1a和1b，并在不同条件下研究了它们的光物理性质以及与各种金属离子的相互作用。由于萘二甲酰亚胺发色团的局部激发态以及来自丹磺酰基部分的能量转移介导的发射（荧光共振能量转移，FRET），这些二元化合物分别在约375和525 nm处显示出双重发射。当用各种金属离子进行滴定分析时，与Na(+)、Li(+)、K(+)、Zn(2+)、Pb(2+)、Hg(2+)、Co(2+)、Fe(2+)、Cd(2+)、Mg(2+)和Ba(2+)离子相比，这些体系对Cu(2+)离子表现出异常的选择性，并通过抑制525 nm处的FRET介导发射以及同时增强375 nm处萘二甲酰亚胺发色团的发射强度来指示结合事件。这些二元化合物的独特之处在于它们形成了涉及磺酰胺官能团的稳定的2:1化学计量比配合物，并作为用于选择性识别Cu(+)离子可视荧光比率探针。
