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A novel fluorescent probe based 1,8-naphthalimide (NFH) for fluoride naked-eye recognition was synthesized, and it displayed high selectivity and sensitivity. The color and fluorescence changes of probe NFH can be observed only in presence of F − among various anions (F − , Cl − , Br − , I − , AcO − , NO 3 − , HSO 4 − , H 2 PO 4 − ). Furthermore, 1 H NMR titration indicated the deprotonation of acylhydrazone ( NH C O) which was induced by the interaction of F − ions and NH moieties. Theoretical calculation based on DFT explored the photoinduced electron transfer (PET) signaling mechanism of NFH toward F − which explained the striking fluorescent quenching of probe NFH after being treated with F − ions. [ABSTRACT FROM AUTHOR]

Based on benzothizazole and 1,8-naphalimide, a novel colorimetric and fluorescent probe (probe 1 ) for fluoride ion was synthesized by Schiff base reaction. The striking yellow-to-blue color change of the probe 1 in the CH 3 CN was observed with the naked eyes only in presence of F − among the eight anions (F − , Cl − , Br − , I − , NO 3 − , HSO 4 − , H 2 PO 4 − , AcO − ). Besides that, upon addition of F − , both of the absorption and emission peaks shifted to near-infrared region (NIR) (>600 nm) in UV–vis and fluorescent spectra, and the detection limit reached as low as 0.41 μM. Furthermore, the 1 H NMR titration and theoretical calculation based on TD-DFT indicated that the fluoride ion induced deprotonation of the probe 1 through hydrogen bonding interaction between amino group of probe 1 and fluoride ion. [ABSTRACT FROM AUTHOR]

A novel coumarin-based compound 1 featuring thiosemicarbazone as binding unit, was reported as a colorimetric and fluorescent probe for the detection of fluoride anion. The addition of F − to a solution of probe 1 in tetrahydrofuran resulted in evident naked-eye color change from green-yellow to orange-red under daylight and obvious fluorescence quenching within 3 s. And the detection limit toward F − was calculated to be as low as 2.16 × 10 −7 mol/L. 1 H NMR titrations proved that the interaction between 1 and fluoride ion: hydrogen bond at low fluoride ion concentration, deprotonation at high fluoride ion concentration. Besides, it exhibited highly sensitivity and selectivity for F − over other examined ions (Cl − , Br − , I − , AcO − , NO 3 − , HSO 4 − , H 2 PO 4 − ) in tetrahydrofuran solution. [ABSTRACT FROM AUTHOR]

A new near-infrared colorimetric and ratiometric fluorescent chemodosimeter for Hg 2+ detection was devised, with a donor-acceptor-donor (D-A-D) molecular configuration and containing a dithioacetal group served as a sensing unit, and with a large stokes shift over 160 nm. The oxidation reaction of Hg 2+ broke the electron-donating interaction of dithioacetal moiety, and the obstruction in the intramolecular charge transfer (ICT) induced remarkable changes in the absorption and emission spectra. The sensor exhibited splendid selectivity and anti-interference performance towards Hg 2+ over other cations (K + , Na + , Ag + , Fe 2+ , Co 2+ , Mn 2+ , Zn 2+ , Ca 2+ , Pb 2+ , Ni 2+ , Mg 2+ , Cu 2+ , Al 3+ , Fe 3+ ). The mechanism was investigated by absorption and emission spectra together with 1 H NMR titration. [ABSTRACT FROM AUTHOR]

A new colorimetric fluorescent probe, 3-benzothiazolyl-coumarin-7-yl picolinate (P1) , based on coumarin derivative has been designed and synthesized to detect Cu 2+ in CH 3 CN-water (1:1,v/v) solution. The probe showed highly selective and sensitive fluorescence enhancement response towards Cu 2+ via selective hydrolysis reaction of the picolinate moiety followed by generating a strongly fluorescent 3-benzothiazolyl-7-hydroxycoumarin ( 2 ) moiety, whereas other competing metal cations (Na + , K + , Mg 2+ , Ag + , Fe 3+ , Pb 2+ , Mn 2+ , Ca 2+ , Ni 2+ , Cr 3+ , Zn 2+ , Sn 2+ , Hg 2+ , Al 3+ , Pd 2+ , Pt 2+ , Co 2+ , Au 3+ ) did not possess the property. Upon the addition of Cu 2+ , the color of P1 changed from colorless to yellow-green, and gave an emission at around 470 nm. Moreover, the detection limit toward Cu 2+ was calculated to be as low as 23.9 nM. [ABSTRACT FROM AUTHOR]

A chemical sensor containing triphenylamine and benzothiadiazole for cyanide anions detection was designed and synthesized, whose structural feature is a donor-acceptor-donor (D-A-D) molecular configuration, which is substituted with a dicyanovinyl group served as a sensing unit. The nucleophilic addition of cyanide ion to the dicyanovinyl moiety was activated in the principle of Michael addition, which broken the electron-withdrawing interaction of dicyanovinyl moiety. The obstruction in the intramolecular charge transfer (ICT) induced remarkable changes in the absorption and emission spectra. The sensor exhibited splendid selectivity and anti -interference performance towards CN − over other anions (F − , Cl − , Br − , I − , NO 2 − , NO 3 − , HCO 3 − , H 2 PO 4 − , HS − , HSO 3 − , NCO − , SCN − , SO 3 2− , SO 4 2− , HPO 4 2− , CO 3 2− ). The mechanism was investigated by absorption and emission spectra together with 1 H NMR titration. [ABSTRACT FROM AUTHOR]

Two novel 2,1,3-benzothiadiazole derivatives, used as colorimetric and fluorescent sensors for fluoride ion were designed, synthesized and characterized. These sensors contained single hydrogen-bond functional groups, which acted as interacting sites for fluoride ion. Both sensors displayed a red color in dimethyl sulfoxide solution. Binding studies revealed that they showed noticeable colorimetric and fluorescent responses only to F − among the eight anions tested (F − , Cl − , Br − , I − , AcO − , H 2 PO 4 − , HSO 4 − and NO 3 − ). 1 H NMR titration proved that the interaction between compounds and fluoride ion: hydrogen bond at low fluoride ion concentration, deprotonation at high fluoride ion concentration. Moreover, those compounds showed high sensitivity and selectivity for fluoride ion by inhibiting the excited state intramolecular proton transfer processes, and the detective processes could be followed by direct visual observation. [ABSTRACT FROM AUTHOR]

In view of palladium contaminants and their adverse effects on human health, it is valuable to develop an effective probe for palladium. In this work, a coumarin-based colorimetric and turn-on fluorescent probe, Cou-1 , for highly selective and sensitive detection of palladium was designed based on the Tsuji–Trost allylic reaction. Upon the addition of palladium to the solution of probe, the probe gave an emission peak at around 498 nm as well as displayed a selective chromogenic behavior toward palladium from colorless to yellow-green, which could be easily observed by the naked eye. Moreover, compared with typical transition metal cations and other common cations used, Cou-1 showed great selectivity toward palladium. Further, the detection limit toward palladium was calculated to be as low as 17.4 nM. [ABSTRACT FROM AUTHOR]