The Rh(iii)-catalysed C–H/N–H annulation of 2-thienyl- and 2-phenyl-quinazolin-4(3H)-ones with diphenylacetylene

2-Thienyl/phenyl substituted quinazolin-4(3H)-ones were converted into 4,5-diphenyl-7H-thieno[2′,3′:3,4]pyrido[2,1-b]quinazolin-7-ones or amide alcoholysis product via Rh(iii)-catalyzed reaction of with diphenylacetylene.

GB, Latiyan S, Jain S. Remarkably selective biocompatible turn-on fluorescent probe for detection of Fe3+ in human blood samples and cells

The robust nature of a biocompatible fluorescent probe is demonstrated, by its detection of Fe³⁺ even after repeated rounds of quenching (reversibility) by acetate in real human blood samples and cells in vitro.

Facile fluorescent labeling of a polyacrylamide-based hydrogel film via radical initiation enables selective and reversible detection of Al3

Stimuli-responsive hydrogels have attracted significant attention for their promising characteristics and have been used in diverse platforms developed for practical applications. When processed as films, these hydrogels show enhanced properties, including faster responses and higher loading capacities, and enhanced interfacial interactions. In this study, we prepared a functional polyacrylamide hydrogel film containing a rhodamine-based probe. The probe plays two fundamental roles: in the fabrication of the film via redox-initiated radical polymerization and in providing a fluorescence response to Al³⁺. The amine-containing probe initiated the polymerization reaction at room temperature; the resulting film synthesized through the one-step reaction was transparent and stretchable, elongating by more than five times under tensile tension. The fluorogenic probe in the film showed a sensitive, selective response to Al³⁺ with a detection limit of 1.5 μM. Furthermore, after detection, the addition of ethylenediaminetetraacetic acid (EDTA) to the film turned off the fluorescence from the probe; this facilitated reversible fluorescence sensing when the film was repeatedly exposed to Al³⁺, as expected. The facile preparation method can be expanded to incorporate other multi-functional amine probes that can impart hydrogel films with autonomous, responsive systems.

A New Polymer-Based Fluorescent Chemosensor Incorporating Propane-1,3-Dione and 2,5-Diethynylbenzene Moieties for Detection of Copper(II) and Iron(III)

A novel conjugated polymer (PDBDBM) was developed by the polymerization of 1,4-dioctyloxy-2,5-diethynylbenzene with 1,3-bis(4-bromophenyl)propane-1,3-dione based on Pd-catalyzed Sonogashira-coupling reaction. The obtained polymer PDBDBM exhibited bright green photoluminescence under UV irradiation. According to the metal ion titration experiments, PDBDBM showed high sensitivity and selectivity for detection of Cu2+ and Fe3+ over other metal ions. The fluorescent detection limits of PDBDBM were calculated to be 5 nM for Cu2+ and 0.4 μM for Fe3+ and the Stern⁻Volmer quenching constant for Cu2+ and Fe3+ were found to be 1.28 × 10⁸ M-1 and 2.40 × 10⁴ M-1, respectively. These results indicated that the polymer can be used as a potential probe for Cu2+ and Fe3+ detection.

The influences of different substituents on spectral properties of rhodamine B based chemosensors for mercury ion and application in EC109 cells

Six rhodamine-based “turn-on” fluorescence chemosensors (L1–L6) with different substituents for mercury (Hg2+) were readily synthesized and investigated; they displayed high selectivity and chelation enhanced ratiometric fluorescence change and colorimetric change with Hg2+ among the metal ions examined. Based on UV and fluorescence spectral data, the effects of different substituents on spectral properties of the probes were presented and discussed. The detection limit of Hg2+ to probe L1 was as low as 50 nmol/L because of its electron-donating group. Theoretical calculation also supported the process of reaction. Confocal laser scanning microscopy experiments showed that probe could be used to detect Hg2+ in living cells.

Rhodamine B-based ordered mesoporous organosilicas for the selective detection and adsorption of Al(iii)

A novel “Off–On” solid chemosensor for Al³⁺ was constructed by combining ordered mesoporous silica with a rhodamine B derivative.

2-(Alkylamino)-3-aryl-6,7-dihydrobenzofuran-4(5H)-ones: Improved Synthesis and their Photophysical Properties

Furans are an important class of compounds and exhibit a diverse range of activities and properties. As such, improved synthetic access to furans is an important research goal. In the present report, a solvent- and catalyst-free reaction between 5,5-dimethyl-1,3-cyclohexanedione (dimedone), an aryl aldehyde and an isocyanide under microwave irradiation is presented. This method is significantly improved from previously described protocols in terms of applicability of wide ranging aryl aldehydes, better yields, shorter reaction times, facile work up and essentially no need of column chromatography. The photophysical properties of this series of compounds were studied for their possible applicability in the field of metal ion sensors. In solution, two compounds, 2-(cyclohexylamino)-3-(1H-indol-3-yl)-6,6-dimethyl-6,7-dihydrobenzofuran-4(5H)-one (1 i) and 2-(tert-butylamino)-3-(1H-indol-3-yl)-6,6-dimethyl-6,7-dihydrobenzofuran-4(5H)-one (1 j), underwent an observable color change from yellow to colorless in the presence of aluminum(III) ions. Further studies to investigate the UV absorption and luminescence behavior of these compounds revealed their utility as "naked-eye sensors" for aluminum detection.

Green synthesis of multifunctional carbon dots from coriander leaves and their potential application as antioxidants, sensors and bioimaging agents

In the present study, a facile one-step hydrothermal treatment of coriander leaves for preparing carbon dots (CDs) has been reported. Optical and structural properties of the CDs have been extensively studied by UV-visible and fluorescence spectroscopic, microscopic (transmission electron microscopy, scanning electron microscopy) and X-ray diffraction techniques. Surface functionality and composition of the CDs have been illustrated by elemental analysis and Fourier transform infrared spectroscopy (FTIR). Quenching of the fluorescence of the CDs in the presence of metal ions is of prime significance, hence CDs have been used as a fluorescence probe for sensitive and selective detection of Fe(3+) ions. Eventually, biocompatibility and bioimaging aspects of CDs have been evaluated on lung normal (L-132) and cancer (A549) cell lines. Qualitative analysis of cellular uptake of CDs has been pursued through fluorescence microscopy, while quantitative analysis using a flow cytometer provided an insight into the concentration and cell-type dependent uptake of CDs. The article further investigates the antioxidant activity of CDs. Therefore, we have validated the practicality of CDs obtained from a herbal carbon source for versatile applications.

A fluorescent “turn on” chemosensor based on Bodipy–anthraquinone for Al(iii) ions: synthesis and complexation/spectroscopic studies

A fluorescent “turn on” Al(iii) chemosensor based-on bodipy–anthraquinone with two triazole ring was prepared and studied for its complexation and spectroscopic properties.