RESUMO
A highly selective femtomolar level sensing of inorganic arsenic(III) as arsenious acid has been accomplished in water medium and in living-systems (on pollen grains of Tecoma stans; Candida albicans cells (IMTECH No. 3018) and Peperomia pellucida stem section) using a non-toxic fluorescent probe of a Cu(II)-complex.
Assuntos
Arsênio/análise , Corantes Fluorescentes/química , Espectrometria de Fluorescência , Poluentes Químicos da Água/análise , Bignoniaceae/química , Bignoniaceae/metabolismo , Candida albicans/química , Complexos de Coordenação/química , Cobre/química , Microscopia de Fluorescência , Peperomia/química , Peperomia/metabolismo , Caules de Planta/química , Caules de Planta/metabolismo , Pólen/química , Pólen/metabolismoRESUMO
A naphthalene-thiophene hybrid molecule (Z)-1-((thiophen-2-ylmethylamino)methylene)naphthalen-2(1H)-one () was prepared by condensation of 2-thiophenemethylamine and 2-hydroxy-1-naphthaldehyde. According to FTIR, (1)H NMR spectrometry and single crystal X-ray analysis, exists in the cis-keto-amine tautomeric form. behaves like a molecular AND type binary logic gate with two inputs viz. Zn(2+) and OAc(-) ions whereby the fluorescence of the system turns on. The structures of and its zinc acetate complex were also optimized by DFT calculations. binds Zn(2+) in a 1 : 1 ratio with an association constant K(a) = 2.05 × 10(4) M(-1), and detects Zn(2+) as low as 3 × 10(-8) M. is useful for the detection of intracellular Zn(2+) under a fluorescence microscope.
Assuntos
Acetatos/química , Corantes Fluorescentes/química , Naftalenos/química , Tiofenos/química , Zinco/química , Candida albicans/isolamento & purificação , Cristalografia por Raios X , Íons/química , Microscopia de Fluorescência , Conformação Molecular , Teoria Quântica , EstereoisomerismoRESUMO
An Al(3+) selective ratiometric fluorescent probe (L) has been synthesized by condensation of 4,5-diaminopyrimidine with 1-pyrenecarboxaldehyde. The structure of L has been confirmed by single crystal X-ray analysis. In the presence of Al(3+), L exhibits a considerable excimer emission at 445 nm along with the decrease of its monomer emission at 368 nm in DMSO-H2O (4 : 1, v/v). The lowest detection limit for Al(3+) is 0.24 µM. Furthermore, L can permeate through the cell membrane and detects intracellular Al(3+) ions under a fluorescence microscope.
Assuntos
Alumínio/análise , Microscopia de Fluorescência , Pirenos/química , Pirimidinas/química , Bacillus/citologia , Candida/citologia , Cristalografia por Raios X , Corantes Fluorescentes/química , Íons/química , Conformação MolecularRESUMO
A visible light excitable rhodamine based probe operates as a SCN(-) selective fluorescent "turn-on" sensor for living cell imaging with a detection limit of 0.01 µM, which is much lower than the normal SCN(-) level in the human body. A "lock" and "key" model has been proposed to explain the fluorescence enhancement of the rhodamine probe in the presence of SCN(-).
Assuntos
Corantes Fluorescentes/química , Luz , Rodaminas/química , Espectrometria de Fluorescência , Tiocianatos/análise , Candida albicans/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/patologia , Humanos , Microscopia de Fluorescência , Fumar , Tiofenos/químicaRESUMO
A new colorimetric fluorescent receptor for H(2)PO(4)(-) is reported in this communication. The receptor can detect dihydrogen phosphates optically by developing a color change from yellow to green. Acute spectral responses to H(2)PO(4)(-) in HEPES buffer (DMSO-HEPES 1:9) have been observed. The selectivity zone in terms of pH of the receptor for H(2)PO(4)(-) is attributed to the fitness in the acidity (pK(a)) of receptor with H(2)PO(4)(-). Hydrogen bonding plays the key role here which is confirmed by (1)H NMR titration. The receptor also has good potential for bio-imaging. The mode of interaction has also been established by ab initio calculation.
Assuntos
Candida albicans/química , Corantes Fluorescentes/química , Fosfatos/análise , Bases de Schiff/química , Candida albicans/citologia , Colorimetria , Corantes Fluorescentes/síntese química , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Estrutura Molecular , Teoria Quântica , Bases de Schiff/síntese química , Solventes/química , Água/químicaRESUMO
Ni(2+)-induced intramolecular excimer formation of a naphthalene-based novel fluorescent probe, 1-[(naphthalen-3-yl)methylthio]-2-[(naphthalen-6-yl)methylthio]ethane (L), has been investigated for the first time and nicely demonstrated by excitation spectra, a fluorescence lifetime experiment, and (1)H NMR titration. The addition of Ni(2+) to a solution of L (DMSO:water = 1:1, v/v; λ(em) = 345 nm, λ(ex) = 280 nm) quenched its monomer emission, with subsequent enhancement of the excimer intensity (at 430 nm) with an isoemissive point at 381 nm. The fluorescence lifetime of free L (0.3912 ns) is much lower than that of the nickel(2+) complex (1.1329 ns). L could detect Ni(2+) as low as 1 × 10(-6) M with a fairly strong binding constant, 2.0 × 10(4) M(-1). Ni(2+)-contaminated living cells of plant origin could be imaged using a fluorescence microscope.
Assuntos
Corantes Fluorescentes/química , Magnoliopsida/citologia , Naftalenos/química , Níquel/análise , Cátions Bivalentes/análise , Cátions Bivalentes/química , Corantes Fluorescentes/síntese química , Microscopia de Fluorescência/métodos , Modelos Moleculares , Naftalenos/síntese química , Níquel/química , Pólen/citologiaRESUMO
A thiophene-coumarin hybrid molecule, (6E)-6-((thiophen-2-yl)methyleneamino)-2H-chromen-2-one (TMC) has been prepared and its single crystal X-ray structure is reported. TMC can selectively detect Cr(3+) in presence of other common cations. Both TMC and its Cr(3+) complex are well characterized by different spectroscopic techniques like (1)H NMR, QTOF-MS ES(+), FTIR and elemental analysis as well. TMC exhibits fluorescence enhancement upon binding Cr(3+) in CH(3)CN-HEPES buffer (0.02 M, pH 7.4) (4:6, v/v) medium. Detection limit of the method is 1 × 10(-6)M. Binding constant is estimated with the Benesi-Hildebrand method and the value 8 × 10(4) indicates a fairly strong interaction between TMC and Cr(3+). Speciation studies have been performed in a fast and environment friendly way using least sample volume, less hazardous chemicals and solvents. Cr(3+) assisted restricted rotation around the imine bond and inhibited photo-induced electron transfer from the N,S-donor sites to the coumarin unit are responsible for fluorescence enhancement. TMC is capable to detect intracellular Cr(3+) in living cells.
Assuntos
Cromo/análise , Técnicas Citológicas/métodos , Diagnóstico por Imagem/métodos , Corantes Fluorescentes/química , Células , Cumarínicos , Cristalografia por Raios X , Estrutura Molecular , TiofenosRESUMO
An efficient Hg(2+) selective fluorescent probe (vanillin azo coumarin, VAC) was synthesized by blending vanillin with coumarin. VAC and its Hg(2+) complex were well characterized by different spectroscopic techniques like (1)H NMR, QTOF-MS ES(+), FTIR and elemental analysis as well. VAC could detect up to 1.25 µM Hg(2+) in aqueous methanol solution through fluorescence enhancement. The method was linear up to 16 µM of Hg(2+). Negative interferences from Cu(2+), Ni(2+), Fe(3+), and Zn(2+) were eliminated using EDTA as a masking agent. VAC showed a strong binding to Hg(2+) ion as evident from its binding constant value (2.2×10(5)), estimated using Benesi-Hildebrand equation. Mercuration assisted restricted rotation of the vanillin moiety and inhibited photoinduced electron transfer from the O, N-donor sites to the coumarin unit are responsible for the enhancement of fluorescence upon mercuration of VAC. VAC was used for imaging the accumulation of Hg(2+) ions in Candida albicans cells.