A New Schiff Base Chemodosimeter: Selective Colorimetric and Fluorescent Detection of Fe (III) Ion.

A new efficient chemosensor 1 was prepared, for the detection of Fe(3+) in solutions as a colorimetric and fluorescent sensor. The visual and fluorescent behaviors of the receptor toward various metal ions were also explored. The receptor shows exclusive response toward Fe(3+) ions and also distinguishes Fe(3+) from other cations by color change and fluorescence enhancement in hydroalcoholic solution (MeOH/H2O = 9/1, v/v). Thus, the receptor can be used as a colorometric and fluorescent sensor for the determination of Fe(3+) ion. The fluorescence microscopy experiments showed that the chemosensor is efficient for detection of Fe(3+) in vitro, developing a good image of the biological organelles. Graphical Abstract ᅟ.

A New Schiff Base Chemodosimeter for Fluorescent Imaging of Ferric Ions in Living Cells.

A new and efficient chemodosimeter for ferric ions has been developed. The visual and fluorescent behaviors of the compound toward various metal ions were investigated: ferric ions are distinguished from other cations by selective color change and unusual fluorescence enhancement in mixed aqueous solution. Fluorescence microscopy experiments showed that this receptor is effective for detection of Fe(3+) in vitro, developing a good image of the biological organelles. The sensing mechanism is shown to involve a hydrolysis process.

Synthesis of alanine-based colorimetric sensors and enantioselective recognition of aspartate and malate anions.

Two chiral colorimetric sensors (1,2) were synthesized and characterized by spectroscopic techniques and their enantioselective recognition of chiral dicarboxylic anions (D/L-aspartate and D/L-malate) was examined by UV-vis and (1)H NMR spectroscopy. Interaction of the receptors 1 and 2 with the enantiomers of aspartate or malate caused different color changes, and they act as optical chemosensors for the recognition of D-aspartate vs. L-aspartate and d-malate vs.l-malate. Receptor 1 exhibits high enantioselective binding for aspartate anions [K(A(D))/K(A(L)) = 12.15].

A new pyrene-based Schiff-base: a selective colorimetric and fluorescent chemosensor for detection of Cu(II) and Fe(III).

A new receptor 1 was prepared, for the detection of Cu2+ and Fe3+ in solutions as a colorimetric and fluorescent sensor, respectively. Receptor 1 shows highly selective and sensitive recognition toward Cu2+ and Fe3+ by naked eye UV-Vis and fluorescent color changes in aqueous solution (DMSO/H2O=8/2, v/v), respectively. The sensitivity toward Cu2+ or Fe3+ was not interfered with by the presence of other metal ions such as Mg2+, Cd2+, Ag+, Zn2+, Ni2+, Co2+, Mn2+, Cr3+, Ca2+, Na+, Pb2+, K+, Fe2+, Li+ and Hg2+ ions. Receptor 1 can be used for semi-quantitative recognition of Cu2+ ions at ppm level. The fluorescence microscopy experiments showed that the receptor is efficient for detection of Fe3+ in vitro, developing a good image of the biological organelles.

A new selective colorimetric and fluorescent chemodosimeter for HSO4(-) based on hydrolysis of Schiff base.

Two new receptors 1 and 2 were prepared, and their chromogenic and fluorogenic behaviors toward various anions were investigated. Receptors 1 and 2 show exclusive response toward HSO4(-) ion and also distinguish HSO4(-) from other anions by different color changes in aqueous solution (CH3CN/H2O=4/1, v/v). Between them receptor 1 selectively exhibits a pronounced HSO4(-)-induced fluorescence enhancement. The detection limit for the HSO4(-) ion was determined as (0.24±0.03µM). Thus, the receptor 1 can be used as a colorimetric and fluorescent sensor for the determination of HSO4(-) ion. The sensing mechanism has been suggested to proceed via a hydrolysis process. The hydrolysis product has been isolated and further identified by (1)H NMR spectroscopy, ESI-MS analysis and X-ray diffraction.

A new dual functional sensor: highly selective colorimetric chemosensor for Fe3+ and fluorescent sensor for Mg2+.

A new artificial receptor 1 was synthesized for the detection of Fe(3+) and Mg(2+) in solution as a colorimetric and fluorescent sensor, respectively. The sensor exhibited highly selective and sensitive recognition towards Fe(3+) in CH(3)CN via color change from colorless to brown. Also it showed a significant fluorescence enhancement (70-fold) towards Mg(2+) in the mixture of solution CH(3)CN/H(2)O (8:2, v/v). The selectivity of either Fe(3+) or Mg(2+) was not interfered by the presence of other metal ions such as Cr(3+), Mn(2+), Co(3+), Ni(2+), Cu(2+), Ag(+), Cd(2+), Pb(2+), Ca(2+) and K(+) ions.

Colorimetric detection of cyanide with phenyl thiourea derivatives.

Three structurally simple thiourea derivatives 1-3 were prepared, and their chromogenic behaviors toward various anions were investigated in aqueous solution. Among them 1 showed good sensitivity and selectivity for cyanide ion and also can distinguish it from other anions by different color changes. Besides that, the receptor 1 has a sensitive detection limit (1.27 µM) for cyanide ion accordingly it can be used as a colorimetric sensor for the determination of cyanide ion. The use of the test strip of sensor 1 to detect cyanide ion was also reported.

A new selective colorimetric and fluorescent sensor for Hg(2+) and Cu(2+) based on a thiourea featuring a pyrene unit.

A new artificial receptor 1 was developed, and its chromogenic and fluorogenic behaviors toward various metal ions were investigated. Receptor 1 shows exclusively responses toward Hg(2+) and Cu(2+) ions. It selectively senses Hg(2+) and Cu(2+) ions through two different color changes in aqueous solution (DMSO/H(2)O=4/1) and also distinguishes them from other metal ions. In addition, receptor 1 also exhibits pronounced enhancements of the fluorescence, which can visually be discernible by an orchid fluorescence in the presence of Hg(2+) ions and a strong blue fluorescence in the presence of Cu(2+) ions.

Synthesis of colorimetric sensors for isomeric dicarboxylate anions: selective discrimination between maleate and fumarate.

Four new colorimetric receptors (1-4) were synthesized and characterized. Upon addition of maleate to receptor in DMSO, the appearance of the solution of receptor 1 showed a color change from dark-blue to dark-red, which can be detected by the naked eye at parts per million. Similar experiments were repeated using receptors 2-4; the solution showed a distinct color change from blue to violet for receptor 2 and from blue-green to purple for both receptors 3 and 4, when they are formed as complexes with maleate. The striking color changes are thought to be due to the deprotonation of the thiourea moiety of the 4-nitronaphthyl chromophore. Whereas, in the addition of fumarate to receptors 1-4, the color of the solution changed from dark-blue to bright yellow for receptor and did not induce any color change for receptors 2-4. Thus, for a distinct color change, receptors 1-4 can act as optical chemosensors for recognition of maleate versus fumarate. Especially, only receptor 1 has a unique color change for the recognition of fumarate, accordingly it can be used for detection of the fumarate anion. In this research it was also found that the performance of the receptor is highly dependent on the substituent group on the phenyl ring; a stronger electron-withdrawing group resulted in a receptor with a higher binding constant with the maleate anion.