Synthesis of new tripodal receptors—a ‘PET’ based ‘off–on’ recognition of Ag+

A ruthenium(iii) complex derived from N,N′-bis(salicylidene)ethylenediamine as a chemosensor for the selective recognition of acetate and its interaction with cells for bio-imaging: experimental and theoretical studies

A ruthenium(iii) complex ofN,N′-bis(salicylidene)ethylenediamine (L¹) was used as chemosensor for the recognition of acetate in cells for bio-imaging.

An ultrasound-assisted ion association dispersive liquid–liquid microextraction coupled with micro-volume spectrofluorimetry for chromium speciation

A micro-volume spectrofluorimetric coupled ultrasound-assisted ion association dispersive liquid–liquid microextraction (USA-IA-DLLME) procedure for the total determination and speciation of chromium(iii & vi) species has been presented.

Nanomolar fluorogenic detection of Al(III) by a series of Schiff bases in an aqueous system and their application in cell imaging

Three positional isomers of a Schiff base containing -OH as end groups have been synthesized and evaluated for selective Al(III) detection due to inhibition of ESIPT, PET and activation of CHEF in 70% aqueous medium. Devoid of any conventional fluorophore, these sensors have nanomolar detection limits with high quantum yields and naked eye sensing of Al(III). Moreover, these probes have been demonstrated to enable the Al(III) detection in live human HeLa cells and rat C6 glioma cells using a confocal microscope.

Fluorescence sensing systems for gold and silver species

Here, we provide an overview of the reported fluorescent detection systems for gold and silver species, and discuss their sensing properties with promising features.

NHC macrometallocycles of mercury(ii) and silver(i): synthesis, structural studies and recognition of Hg(ii) complex 4 for silver ion

Seven NHC macrometallocycles (Hg(ii) and Ag(i)) were prepared, and the recognition of Ag⁺ using (NHC)₂–Hg–I₂ (4) as a host was studied.

Organic–inorganic nanohybrids and their applications in silver extraction, chromogenic Cu2+ detection in biological systems, and hemolytic assay

An organic–inorganic nanohybrid material is prepared for chemosensor development in aqueous media.

Pyrene pyridine-conjugate as Ag selective fluorescent chemosensor

A new pyrene pyridine conjugate (PPC) has been developed as a selective fluorescent sensor for Ag⁺ion.

Surfactant Sensitized Calix[4]arenes Fluorescence Quenching Method for Speciation of Cr(VI)/Cr(III) in Water Samples

The surfactant sensitized spectrofluorimetry for speciation of chromium (Cr(VI)/Cr(III)) was developed. The analytical procedure was that the fluorescence intensity of l4,10,16,22-tetramethoxyl resorcinarene carboxylic acid derivatives (TRCA) could be selectively quenched by Cr(VI) and the fluorescence quenching value (ΔF=FTRCA-FCr(VI)-TRCA) was increased in cetyltrimethylammonium bromide (CTAB). The main influence factors on the fluorescence quenching (ΔF) were investigated in detail. Under the optimal conditions, the linear range of calibration curve for the determination of Cr(VI) was 0.10~5.00 μg/mL, and the detection limit was 0.024 μg/mL with RSD=2.10% (c=1.0 μg/mL, n=3). The concentration of Cr(III) was calculated by subtracting Cr(VI) from the total chromium determined after oxidizing Cr(III) to Cr(VI). The preliminary sensitized mechanism was discussed with the inclusion constant (K) of TRCA-Cr(VI), the fluorescence quantum yield of TRCA, and IR spectra characterization. The method has been applied to the speciation analysis of Cr(VI)/Cr(III) in water samples.

Dual channel selective fluorescence detection of Al(III) and PPi in aqueous media with an 'off-on-off' switch which mimics molecular logic gates (INHIBIT and EXOR gates)

In this study, we have synthesized a simple Schiff base type isophthaloyl salicylaldehyde hydrazone (ISH) moiety which selectively detects Al(III) and PPi with a fluorescence enhancement at two different wavelengths in aqueous solution. The sensing phenomenon is also reversible and thus the sensor beautifully mimics logic gates (INHIBIT and EXOR gates).

Recent progress in fluorescent and colorimetric chemosensors for detection of precious metal ions (silver, gold and platinum ions)

Due to the wide range of applications and biological significance, the development of optical probes for silver, gold and platinum ions has been an active research area in the past few years. This tutorial review focuses on the recent contributions concerning the fluorescent or colorimetric sensors for these metal ions, and is organized according to their structural classifications (for Ag(+) detection) and unique mechanisms between the sensors and metal ions (for Au(3+) and Pt(2+) detection).

An easy assembled fluorescent sensor for dicarboxylates and acidic amino acids

Two mesitylene based neutral receptors 1 and 2 bearing two thiourea binding sites were constructed as fluorescent probes for sensing dicarboxylates. Their binding affinities toward dicarboxylates, aspartate and glutamate have been investigated in acetonitrile solution by fluorescence titration experiments. Both fluorescent sensors exhibited some ability to discriminate the antipodal forms of aspartate and glutamate.

A multifunctional tripodal fluorescent probe: "off-on" detection of sodium as well as two-input AND molecular logic behavior

A simple tripodal sensor (3) with multifunctional capability has been synthesized in three steps. The sensor, a naphthalene-functionalized Schiff base, displays selectivity for sodium over other important physiological and environmentally important cations through changes in the emission spectra at lambda(max) 355 nm when excited at 270 nm. Interestingly, the combined addition of both sodium and potassium produced a new band at lambda(max) 445 nm, while the addition of sodium or potassium alone produced negligible changes at this wavelength. Therefore, the conditions of a two-input AND logic operator were also satisfied.

Fluorescent recognition of potassium and calcium ions using functionalised CdSe / ZnS quantum dots

Schiff base receptor 1a has been synthesised and attached to the surface of preformed CdSe/ZnS Quantum Dots (QDs) to form QD-conjugate 2a. While 1a was determined to be selective for Mg2+, 2a demonstrated selectivity for both K+ and Ca2+ when tested against a range of physiologically and environmentally relevant cations by changes in the fluorescence spectra. Thus, the nanoparticle surface functions as a scaffold for the organisation of receptors enabling semi-selective binding. The fluorescence response was shown to be linear between 15-50 microM for K+ and 2-35 microM for Ca2+. It was also demonstrated that 2a could measure both K+ and / or Ca2+ in solutions containing both ions.