A dipodal molecular probe for naked eye detection of trivalent cations (Al3+, Fe3+and Cr3+) in aqueous medium and its applications in real sample analysis and molecular logic gates

A simple and low cost multifunctional colorimetric receptor L has been designed, synthesized and characterized by 1H-NMR, IR spectroscopy, ESI-MS spectrometry and elemental analysis. The chemosensor L can selectively detect three biologically and environmentally important trivalent metal ions (Al3+, Fe3+and Cr3+) both visually and spectrophotometrically in CH3CN-H2O (1 : 1, v/v) solution in the presence of other biologically relevant metal ions. The Job's plot analyses indicate the 2 : 2 binding stereochemistry for Al3+, Fe3+ and Cr3+ ions with L, which was further confirmed by 1H-NMR and ESI-MS studies. The binding constant values were found to be 2.9 × 104 M-1 for Al3+, 1.079 × 105 M-1 for Fe3+ and 1.366 × 105 M-1 for Cr3+ respectively. The detections limits of the sensor for Al3+ (2.8 × 10-7 M), Fe3+ (1.9 × 10-7 M) and Cr3+ (2.5 × 10-7 M) are far below than the limit set by the World Health Organization (WHO) for drinking water. Moreover, colorimetric test kits for rapid detection of Al3+, Fe3+, and Cr3+ could be successively applied for all practical purposes, indicating its potential use in environmental samples. It has also been used in building molecular logic gates.

A uniquely fabricated Cu(ii)-metallacycle as a reusable highly sensitive dual-channel and practically functional metalloreceptor for Fe3+ and Ca2+ ions: an inorganic site of cation detection

Dimeric Cu(ii)-complex developed from disulfane ligand, serves as dual-channel metalloreceptor for Fe³⁺/Ca²⁺ and detection of Fe³⁺ in real water samples.

Hydrazinopyrimidine derived novel Al3+ chemosensor: molecular logic gate and biological applications

For the first time, a hydrazinopyrimidine based chemosensor has been designed for sensing Al³⁺ through CHEF-PET-ESIPT fluorescence mechanisms and by building an ‘INHIBIT’ molecular logic gate.

A multi-responsive thiosemicarbazone-based probe for detection and discrimination of group 12 metal ions and its application in logic gates

A new simple 3-in-1 multi-response thiosemicarbazone-based chemosensor has been synthesized and characterized.

A rhodamine-based fluorescent chemosensor for Al3+: is it possible to control the metal ion selectivity of a rhodamine-6G based chemosensor?

A rhodamine derivative 3′,6′-bis(ethylamino)-2-(2-(2-hydroxy-5-methylbenzylideneamino)ethyl)-2′,7′-dimethylspiro[isoindoline-1,9′-xanthen]-3-one has been found to be highly selective and sensitive chemosensor for Al³⁺ ion.

Sequential Detection of CN- and HSO4- Anions in an Aqueous Environment Utilizing a New Colorimetric Azoimine Receptor: Mimicking Logic Gate Behaviour and a Security Keypad Lock

A new isonicotiamide-based azoimine receptor has been successfully devised and synthesised for dual-recognition of CN− and HSO4− anions in aqueous media (3 : 2 DMSO–water solution). The devised azomethine probe detected lethal cyanide ions under UV-vis spectroscopy through the rapid appearance of an orange colour. More importantly, the colour and spectroscopic changes of the devised chemosensor could be revived upon the addition of HSO4− to the sensor containing cyanide ions. Furthermore, other surveyed anions failed to induce a similar response. Interestingly, based on changes in absorption intensity at a particular wavelength in the presence of two aforementioned anions, as two chemical inputs, an INHIBIT logic gate has been elaborated. Moreover, the reversibility of the sensory system provided an opportunity to present a sequential logic circuit at a molecular level. In accession, the target chemosensor could operate as a molecular keypad lock with sequential chemical inputs of CN− and HSO4− anions.

Signalling probes appended with two rhodamine derivatives: inter-component preferences, Fe(iii)-ion selective fluorescence responses and bio-imaging in plant species

Molecular probes (1 and 2) incorporating two different xanthene dyes exhibited Fe(iii) selective dual mode signaling responses.