A New Fluorescent Chemosensor for Copper Ions Based on Tripeptide Glycyl−Histidyl−Lysine (GHK)
ABSTRACT [structure: see text]. A new fluorescent chemosensor for Cu2+ ions was synthesized by modifying the tripeptide glycyl-histidyl-lysine (GHK) with 9-carbonylanthracene via the standard Fmoc solid-phase peptide synthesis method. While significant fluorescence quenching was observed from the molecule upon binding with Cu2+, addition of Fe2+, Co2+, Ni2+, and Zn2+ to the peptide solution caused a minimum fluorescence emission spectral change, indicating a high specificity of this chemosensor for Cu2+ ions. Effects of pH were also investigated.
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- "The two units are linked to each other in such a way that the binding of an imidazolate anion to the ionophore causes considerable changes in the fluorescence of the fluorophore. Such changes can be intensity, intensity ratio, anisotropy, time-domain lifetime or phase-modulation lifetime, etc (Zheng et al., 2001). The high sensitivity and abundance of fluorophores makes fluorescence technique among one of the most promising tools for chemo-and biosensor development. "
ABSTRACT: Metalloporphyrin Complexes play significant roles in many biological and catalytic systems. The diversity of their functions is due in part to the variety of metals that bind in the "pocket" of the porphyrin ring system. Two kinds of metalloporphyrin derivatives, Cu (II) and Zn (II) protoporphyrins (PP), were microscale synthesized ((1) and (2)) and characterized by spectroscopic methods and magnetic measurements. A PP ligand bound to each metal center in a tetradentate fashion including four amine nitrogen atoms in the equatorial planes. These complexes were found to recognize imidazolyl groups of histidine and histamine derivatives as guest molecules by coordination and additional non-covalent interactions. These added analytes displace the selective fluorescent indicator, which when released to the solution displays its full fluorescence. Thus, analyte recognition is signaled by the sharp appearance of the fluorescence of the indicators. The binding affinities of (1) and (2) to histidine and histamine were investigated and accounted for different complexation properties. Moreover, we demonstrated that careful choice of a fluorescent indicator with tuned affinity toward the receptor can provide discrimination in sensing of a desired substrate and the role that the metal coordination plays on the hypsochromic shift and loss of fluorescence distincted characteristics of hypsoporphyrins were also discussed.
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ABSTRACT: The new twistophane macrocycles 2 and 3 have been synthesised; these compounds are composed of a cyclically conjugated dehydrobenzoannulene framework that incorporates 6,6'-connected-2,2'-bipyridine moieties for the purpose of coordinating metal ions. The cyclophanes were characterised by spectroscopic techniques, and shown by molecular mechanics calculations to be helically twisted and chiral molecules that may exist in several possible ground state conformations. UV/vis spectroscopic studies revealed that 2, 3 and precursor 9 bind with different selectivities to particular members of the following small group of metal analytes: CuII, AgI, HgII, Tl1 and PdII. Significantly, 2, 3 and 9 signal the presence of CuII ions through fluorescence emission quenching output responses. Furthermore, cyclophane 3 exhibited a particularly sensitive protontriggered chromogenic fluorescence response. With respect to their unique structural features, high analyte selectivity coupled with their enhanced and characteristic fluorescence emission responses, these molecules are among the first examples representing a new lead class of chemosensory materials. Compounds 2, 3 and 9 and derivatives thereof may, therefore, be expected to find many future applications in the detection of metal-based environmental pollutants, biologically important trace elements and monitoring proton fluxes.Chemistry 11/2002; 8(22):5250-64. DOI:10.1002/1521-3765(20021115)8:22<5250::AID-CHEM5250>3.0.CO;2-Q · 5.73 Impact Factor