Structurally simple azo based chromogenic R1 for the selective sensing of cyanide ion in aqueous medium.

Structurally simple azo linked Schiff base R1 was synthesized and characterized using IR, H NMR and mass spectroscopic techniques. The selective sensing of cyanide anion over other anions such as fluoride, chloride, bromine, iodide, acetate, nitrate, hydrogen sulphate and dihydrogenphosphate was revealed by naked-eye color change and UV-vis spectra. Addition of CN ions to the R1 showed a dramatic change in color from pale yellow to intense yellow along with the formation of a new band at 415nm in the absorption spectrum even in 100% aqueous medium.

Highly Fluorescent Imidazole Probes for the Pico Molar Detection of CN(-) ion and Application in Living Cells.

A series of four imidazole based fluorescent receptors (R1-R4) containing two different signaling units were synthesized for the sensing of specific anions. R1 and R2 act as excellent colorimetric sensors via color change from yellow to orange and pink in presence of F (-) , AcO (-) and CN (-) ions. R1 and R2 show intramolecular charge transfer (ICT) band at 414 nm and 434 nm and were red shifted into 500 nm and 510 nm respectively, with the addition of above anions.

Colorimetric detection of in situ metal acetates and fluorides by a bipyridyl-linked Schiff base.

Here, we present a new bipyridyl moiety linked Schiff base (bipy-1) that is well characterized using spectroscopic techniques. Colorimetric and UV-vis titrations were used to study the photophysical properties of bipy-1 in the presence of various tetrabutyl ammonium salt of anions and metal salts containing different counter cations. bipy-1 showed selective recognition of dimethyl sulphoxide solution of tetrabutyl ammonium salt of F(-) ion accompanied with a UV-vis band at 529 nm and interesting binding of aqueous Co, Ni, and Cu acetates/fluorides, as confirmed by distinct color changes from fluorescent green to pink or orange and a strong band around 480-510 nm in the UV-vis spectrum.

Naked eye sensing of toxic metal ions in aqueous medium using thiophene-based ligands and its application in living cells.

Thiophene-based diimine (R1) and monoimine (R2) were synthesized in a single step, and their cation binding affinity was tested using colorimetric and UV-vis spectral studies. R1 selectively shows a colorimetric turn-on response for Pb(2+), Hg(2+) ions and colorimetric turn-off with Sn(2+) ions, and R2 shows visual response for Cu(2+) and Hg(2+) over other examined metal ions in aqueous medium. R1 forms 1:1 complex with Pb(2+), Hg(2+), and Sn(2+) and exhibits fluorescence quenching, whereas R2 shows 2:1 complex with Hg(2+), Cu(2+) and shows fluorescence enhancement.

Simple azo-based salicylaldimine as colorimetric and fluorescent probe for detecting anions in semi-aqueous medium.

A series of novel, highly sensitive, and selective azo-based anion sensors 1-3 have been designed and synthesized from the condensation reaction between 4-amino azo benzene and three different aldehydes. The structure of the sensors 1-3 were confirmed by IR, HRMS, (1)H NMR, and (13)C NMR spectroscopic methods. Colorimetric naked-eye analysis revealed the anion detection by receptors 2 and 3 as color changes from yellow to pink and yellow to orange, respectively.

Pyrrole based Schiff bases as colorimetric and fluorescent chemosensors for fluoride and hydroxide anions.

An efficient colorimetric sensor with pyrrole-NH moiety as binding site and nitro group as a signaling unit has been synthesized by a one step procedure and characterized by spectroscopic techniques, which displays excellent selectivity and sensitivity for fluoride and hydroxide ions. The hydrogen bonding with these anions provides remarkable colorimetric responses. (1)H NMR and FT IR studies has been carried out to confirm the hydrogen bonding.