An INHIBIT logic gate from a thiophene derivative using iron and zinc ions as the input: tuning the efficiency on moving from naphthalene to anthracene to pyrene for the green luminescent detection of the intracellular iron.

A pyrene-thiophene conjugate has been used for the efficient detection of intracellular irons through the generation of bright green luminescence. Amongst three different probes being reported, it is observed that the efficiency for the naked eye green luminescent detection of iron increases on moving from naphthalene to anthracene to pyrene. The developed technique may be very useful to monitor iron and zinc supplementation as single micronutrients in living systems through the construction of an INHIBIT logic gate.

Selective sensing of Hg²âº using rhodamine-thiophene conjugate: red light emission and visual detection of intracellular Hg²âº at nanomolar level.

Rhodamine-thiophene conjugate (L) has been synthesized and characterized by (1)H NMR, FTIR and mass spectra. L shows a large enhancement in emission intensity in presence of Hg(2+). Moreover, naked eye color of L becomes intense red in presence of Hg(2+). The lowest detection limit for Hg(2+) is 1 × 10(-9)M in HEPES buffer (0.1M in EtOH/water, 1/1, v/v, pH 7.4). Hg(2+) induced chelation enhanced fluorescence (CHEF) is associated with spirolacram ring opening of the rhodamine unit. Trace level intracellular Hg(2+) is visualized under fluorescence microscope.

Rhodamine-based fluorescent probe for Al3+ through time-dependent PET-CHEF-FRET processes and its cell staining application.

Rhodamine-diformyl p-cresol conjugate (L) has been developed as a novel Al(3+)-selective fluorometric and colorimetric sensor based on the FRET mechanism for the first time. L can selectively detect Al(3+) through time-dependent PET-CHEF and FRET processes. This phenomenon is nicely reflected from (1)H NMR, fluorescence lifetime, and fluorescence cell imaging studies. The probe can detect Al(3+) as low as 5 × 10(-9) M in HEPES-buffered EtOH:water (0.1 M, 4:1, v/v, pH 7.4). The probe shows pH-dependent emission properties viz. an intense red emission (585 nm) at acidic pH and an intense green fluorescence (535 nm) at basic pH. Thus, L can also be used as a pH sensor via tunable wavelength.

Nickel(II)-induced excimer formation of a naphthalene-based fluorescent probe for living cell imaging.

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.

pH dependent separation of uranium by chelation chromatography using pyridine 2,6-dimethanol as a chelator: single crystal X-ray structural confirmation of the chelated uranium complex.

A very effective sorbent material which exhibits exceptional capture of hexavalent uranium from other actinides and lanthanides at microg g(-1) level, features pyridine 2,6-dimethanol immobilized onto alumina. The maximum sorption capacity for dioxouranium(VI) was found as 1.96 mmol g(-1) at pH 3.0. The adsorbed uranium complex was eluted completely by 0.05 mol L(-1) (NH(4))(2)CO(3) solution and the concentration of hexavalent dioxouranium ion was monitored spectrophotometrically using Arsenazo III. The structure of the chelated uranium complex has been confirmed by single crystal X-ray structure analysis and Fourier transform infrared red (FTIR) spectroscopy. Thermo gravimetric analysis/differential thermo gravimetric analysis (TGA/DTG) of the chelated uranium complex was performed. The method is reproducible with a relative standard deviation (RSD) of 1.2% (N=10) and the three sigma detection limits (N=15) 1.2 microg mL(-1) respectively. A pre-concentration factor, almost 500, for uranium was achieved. Interferences from Th(4+), Mn(2+), Ni(2+) and Cu(2+) ions were masked with ethylene diamine tetra acetic acid (di-sodium salt) (Na(2)EDTA) in the aqueous phase. The developed method has been tested for uranium recovery and estimation in some certified reference materials and environmental samples.