Organic polymorphs based on an AEE-active tetraphenylethene salicylaldehyde Schiff-base derivative: the effect of molecular conformation on luminescence properties.

An aggregation-enhanced emission (AEE)-active tetraphenylethene salicylaldehyde Schiff-base derivative, TPE-Nap, was prepared using a facile synthesis. The AEE property of TPE-Nap was studied by luminescence and absorption spectra, and was attributed to the C[double bond, length as m-dash]N isomerization restriction and the excited-state intramolecular proton transfer (ESIPT) process. Polymorphs TPE-Nap-Y and TPE-Nap-O were prepared from TPE-Nap, and their emission color and intensity were compared.

A cyanide-sensing detector in aqueous solution based on anion-π interaction-driven electron transfer.

A "turn on" fluorescent and colorimetric sensor, HAT(CN)6, was developed for the light-up detection of cyanide. It was implemented through its strong anion-π interaction, inducing thermal CN- → HAT(CN)6 electron transfer, to give the dianion product [HAT(CN)6]2-, which exhibits unexpected fluorescence. The sensor shows high selectivity, rapid response and a low detection limit towards CN- in aqueous solution, hence indicating its enormous potential in practical applications.

Fluorescence light-up detection of cyanide in water based on cyclization reaction followed by ESIPT and AIEE.

Schiff base 1 (2,4-di-tert-butyl-6-((2-hydroxyphenyl-imino)-methyl)phenol) containing two hydroxyl groups could undergo an oxidative cyclization reaction and then generate hydroxyphenylbenzoxazole (HBO) 2 when CN was present as a catalyst. The multistep cyclization reaction was proved by spectroscopy, H NMR, C NMR and mass spectra. C[double bond, length as m-dash]N isomerization is the predominant decay process of the excited states, so sensor 1 is weakly emissive in solution at ambient temperature.

Gelation-driven selection in dynamic covalent C[double bond, length as m-dash]C/C[double bond, length as m-dash]N exchange.

Knoevenagel barbiturate derivatives bearing long alkyl chains were proven to form organogels in suitable solvents based on supramolecular interactions. Their reaction with imines allows for component exchange through C[double bond, length as m-dash]C/C[double bond, length as m-dash]N recombination. The effect of various parameters (solvents, chain length, and temperature) on the C[double bond, length as m-dash]C/C[double bond, length as m-dash]N exchange reaction has been studied.

Single sensor for multiple analytes in different optical channel: Applying for multi-ion response modulation.

A Schiff-base, (2,4-di-tert-butyl-6-((2-hydroxyphenyl-imino)-methyl)phenol) (L), has been improved to function as a simultaneous multi-ion probe in different optical channel. The probe changes from colorless to orangish upon being deprotonated by F, while the presence of Al significantly enhances the fluorescence of the probe due to the inhibition of CN isomerization, cation-induced inhibition of excited-state intramolecular proton transfer (ESIPT), and chelation enhanced fluorescence (CHEF). Dual-channel "off-on" switching behavior resulted from the sequential input of F and Al, reflecting the balance of independent reactions of Al and F with L and with one another.

A novel cascade strategy with supramolecular and chemodosimetric methods for designing a fluorescent ratiometric detector hypersensitive to trace water.

An intensely fluorescent zinc-salicylideneimine complex (-Zn(II)) was developed as a fluorescent ratiometric detector for the quantitative determination of trace water contents both in THF and methanol. It works based on a water-triggered cascade process: the dissociation reaction of the supramolecular ensemble and the subsequent hydrolysis reaction of its ligand.

An efficient phase-selective gelator for aromatic solvents recovery based on a cyanostilbene amide derivative.

Two novel low molecular weight organogelators (LMOGs) 1 and 2 composed of a cholesteryl group, an amide group and various terminal cyanostilbene moieties were synthesized. They could form stable gels in p-xylene. In particular, 2 with more extended π-conjugation length showed remarkable gelation ability in many aromatic solvents, chloroform and chloroform-containing mixed solvents at a relatively low concentration.

A highly selective fluorescent sensor for Al³⁺ and the use of the resulting complex as a secondary sensor for PPi in aqueous media: its applicability in live cell imaging.

An easy-to-make salicylimine (L) bearing an "O-N-O"-coordination site was used as a highly selective fluorescent sensor for Al(3+) and PPi in aqueous solution. Sensor L showed a significant fluorescence enhancement in the presence of Al(3+) over other competitive metal ions. It works based on the Al(3+)-induced formation of a 1 : 1 L-Al(3+) complex, producing a chelation-enhanced fluorescence effect, the fluorescence quantum yield reached 0.

A real-time fluorescent sensor specific to Mg2+: crystallographic evidence, DFT calculation and its use for quantitative determination of magnesium in drinking water.

An "off-the-shelf" fluorescence "turn-on" Mg(2+) chemosensor 3,5-dichlorosalicylaldehyde (BCSA) was rationally designed and developed. This proposed sensor works based on Mg(2+)-induced formation of the 2 : 1 BCSA-Mg(2+) complex. The coordination of BSCA to Mg(2+) increases its structural rigidity generating a chelation-enhanced fluorescence (CHEF) effect which was confirmed by single crystal XRD studies of the BSCA-Mg(2+) complex and TD/DFT calculations.

A dual channel optical detector for trace water chemodosimetry and imaging of live cells.

A novel 3-5-dichlorosalicylaldehyde Schiff base chemodosimeter (compound 1) for water is designed and synthesized, and it works based on a water-triggered reaction of a Schiff base. Addition of trace amounts of water into 1 in various organic solvents leads to a fluorescence turn-on response and a simultaneous dual-channel signal modulation (both in the fluorescence and absorption spectra). Especially, 1 is found to be an outstanding fluorescence enhancement water sensor in methanol with an extremely low detection limit of 22 ppm.