A colorimetric and fluorometric NBD-based chemosensor for highly selective recognition of palladium(ii) cations

A chemosensor NBD-PMA with colorimetric and fluorometric responses for Pd²⁺ cations has been described.

Promising ESIPT-based fluorescence sensor for Cu2+ and CN− ions: investigation towards logic gate behaviour, anticancer activities and bioimaging application

An excited state intramolecular proton transfer (ESIPT) process-based novel chromogenic and fluorogenic probe (2) was synthesized with the aim of sequential in situ detection of Cu²⁺ and CN⁻ ions under aqueous and biological conditions.

A novel fluorescein-based colorimetric probe for Cu2+ detection

A new colorimetric probe, 5-chlorosalicylaldehyde fluorescein hydrazone (CSFH), has been synthesized and characterized by, FT-IR, NMR, mass elemental analysis and X-ray single crystal diffraction.

A simple and reversible fluorescent probe based on NBD for rapid detection of hypochlorite and its application for bioimaging

A simple and reversible fluorescent probe bearing 7-nitrobenz-2-oxa-1,3-diazole and a selenomorpholine fragment was designed and synthesized.

A colorimetric chemosensor for the sequential detection of copper ion and amino acids (cysteine and histidine) in aqueous solution

A simple and selective colorimetric chemosensor was reported for the sequential detection of Cu²⁺, cysteine and histidine.

4-(8-Quinolyl)amino-7-nitro-2,1,3-benzoxadiazole as a new colorimetric probe for rapid and visual detection of Hg2+

4-Amino-7-nitro-2,1,3-benzoxadiazole (ANBD) usually serves as a scaffold for developing fluorescent probes. In this paper, however, ANBD has been used as a chromogenic unit to design a new colorimetric probe, 4-(8-quinolyl)amino-7-nitro-2,1,3-benzoxadiazole (1), for rapid and visual detection of Hg(2+). The reaction of 1 with Hg(2+) in NaH(2)PO(4)-Na(2)HPO(4) buffer (pH 7.0) containing 70% (v/v) acetonitrile forms a 1:1 complex, accompanying a red shift of the absorption maximum from 482 nm to 557 nm and a distinct color change from orange to violet. Moreover the color reaction exhibits a high selectivity and sensitivity to Hg(2+) only, instead of other common metal ions. This behavior may be ascribed to the formation of a specific 1-Hg(2+) complex, which is supported by (1)H NMR titration experiments. The present study is not only a supplement to the detection method of Hg(2+), but also a merit to the chemistry of 4-amino-7-nitro-2,1,3-benzoxadiazole.

Colorimetric detection of copper ions based on a supramolecular complex of water-soluble polythiophene and ATP

A colorimetric probe for the detection of copper(II) ions in aqueous media by the naked eye has been developed based on a supramolecular complex comprised of a cationic polythiophene derivative and ATP with a detection limit as low as 0.05 mM.

Nickel(II) and iron(III) selective off-on-type fluorescence probes based on perylene tetracarboxylic diimide

Two novel "turn-on" fluorescent probes with perylene tetracarboxylic diimide (PDI) as the fluorophore and two different di-(2-picolyl)-amine (DPA) groups as the metal ion receptor (PDI-1 and PDI-2) were successfully synthesized with satisfactory yields. PDI-1 exhibited high selectivity toward Ni(2+) in the presence of various other metal cations including Zn(2+), Cd(2+) and Cu(2+) which were expected to interfere significantly. A 1 : 2 stoichiometry was found for the complex formed by PDI-1 and Ni(2+) by a Job's plot and by non-linear least square fitting of the fluorescence titration curves. By introducing an extra diamino ethylene group between DPA and the phenyl bridge, the receptor was modified and the high selectivity of the sensor toward Ni(2+) shifted to Fe(3+). The enhancement factor of the fluorescence response of PDI-2 to Fe(3+) was as high as 138. The binding behavior of the receptors in these two compounds is affected significantly by the PDI fluorophores. Most interestingly, both Ni(2+) and Fe(3+) are paramagnetic metal ions, which are known as fluorescence quenchers and are rarely targeted with "turn-on" fluorescence probes. This result suggests that PDIs are favorable fluorophores for a "turn-on" fluorescence probe for paramagnetic transition metal ions because of their high oxidation potential.

Molecular logic and computing

Molecular substrates can be viewed as computational devices that process physical or chemical 'inputs' to generate 'outputs' based on a set of logical operators. By recognizing this conceptual crossover between chemistry and computation, it can be argued that the success of life itself is founded on a much longer-term revolution in information handling when compared with the modern semiconductor computing industry. Many of the simpler logic operations can be identified within chemical reactions and phenomena, as well as being produced in specifically designed systems. Some degree of integration can also be arranged, leading, in some instances, to arithmetic processing. These molecular logic systems can also lend themselves to convenient reconfiguring. Their clearest application area is in the life sciences, where their small size is a distinct advantage over conventional semiconductor counterparts. Molecular logic designs aid chemical (especially intracellular) sensing, small object recognition and intelligent diagnostics.

Fluorescent CXCR4 chemokine receptor antagonists: metal activated binding

A novel rhodamine-azamacrocycle conjugate has been synthesised that can be activated to bind to a specific cell surface receptor by complexation of a copper(ii) ion.

The copper(ii) complex of a novel rhodamine-azamacrocycle conjugate binds to the CXCR4 chemokine receptor and competes effectively against anti-CXCR4 monoclonal antibodies. The copper macrocycle unit adopts a trans-II configuration in the solid state.

Carbohydrate-Based Switch-On Molecular Sensor for Cu(II) in Buffer: Absorption and Fluorescence Study of the Selective Recognition of Cu(II) Ions by Galactosyl Derivatives in HEPES Buffer

[graph: see text] 1-(Beta-D-galactopyranosyl-1'-deoxy-1'-iminomethyl)-2-hydroxynaphthalene (L1), possessing an ONO binding core, was found to be selective for Cu2+ ions in N-[2-hydroxyethyl]piperazine-N'-[2-ethanesulfonic acid] buffer, at concentrations < or = 580 ppb, at physiological pH by eliciting switch-on behavior, whereas the other ions, viz., Mg2+, Ca2+, Mn2+, Fe2+, Co2+, Ni2+, Zn2+, and Cd2+, caused no significant change in the fluorescence. Whereas the binding characteristics were ascertained by absorption spectroscopy, the species formed were shown by Q-TOF ES MS.

Hg2+-Selective OFF−ON and Cu2+-Selective ON−OFF Type Fluoroionophore Based upon Cyclam

[structure: see text]. A new cyclam derivative having two different fluorophores of pyrene and NBD subunits was prepared, and its Hg2+- and Cu2+-selective signaling behaviors were investigated. The detection limits for the analysis of Hg2+ and Cu2+ ions were found to be 7.9 x 10(-6) and 2.6 x 10(-7) M in aqueous acetonitrile solution (H2O-CH3CN = 10:90, v/v), respectively. The compound also exhibited a selective Hg2+/Cu2+-induced OFF-ON-OFF type of signaling pattern that can be utilized for the construction of functional supramolecular switching systems.