ABSTRACT
Graphene quantum dot-covalently appended terpyridine, GQDs-tpy, was synthesized and characterized by X-ray photoelectron spectroscopy, FTIR spectroscopy and transmission electron microscopy. GQDs-tpy was found to act as multifunctional chemosensors: a highly selective colorimetric chemosensor for Fe2+ as evidenced by an obvious color change from colorless to pink, and a typical fluorescence enhanced probe for Zn2+ over 13 metal cations even in practical water samples. Moreover, two-input XOR, INHIBIT and IMPICATION logic gates as well as four-input OR and NOR logic gates were constructed according to the characteristic responses of GQDs-tpy to a sequence of cations.
Subject(s)
Graphite/chemistry , Logic , Pyridines/chemistry , Quantum Dots/chemistry , Molecular Conformation , Optical PhenomenaABSTRACT
A ruthenium(II) complex [Ru(bpy)2(HL(1))](ClO4)2·3H2O {bpy=2,2'-bipyridine and HL(1)=2-(2,6-di(pyridin-2-yl)pyridin-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline}, denoted as RuHL(1), was synthesized and characterized by elemental analysis, proton nuclear magnetic resonance spectroscopy, and mass spectrometry. The pH effects on the UV-visible (UV-vis) absorption and emission spectra and the luminescence lifetimes of RuHL(1) have been studied, and their ground- and excited-state acid ionization constants were derived. The complex was found to exhibit pH-induced "off-on-off" luminescence switching properties via protonation/deprotonation of the grafted imidazole and terpyridyl groups. A pH-induced emission on-off intensity ratio of 166 was observed as pH was increased from 2.00 to 5.44, which is one of the largest values observed among imidazole-containing Ru(II) complex-based acidic-pH-induced pH luminescence switches. RuHL(1) also strongly binds to calf thymus DNA in mixed binding modes involving classic intercalation and partial intercalation, as determined by UV-vis absorption and emission spectrophotometric DNA titration, ethidium bromide displacement, DNA denaturation and DNA viscosity measurements.
