Fluorescent “OFF–ON” Sensors for the Detection of Sn²⁺ Ions Based on Amine-Functionalized Rhodamine 6G

These structurally isomeric rhodamine 6G-based amino derivatives are designed to detect Sn2+ ions. The receptors exhibit rapid fluorescent “turn-on” responses towards Sn2+. The absorption (530 nm) and fluorescent intensity (551 nm) of the receptors increase when increasing the concentration of Sn2+. The hydrazine derivative exhibits more rapid sensitivity towards Sn2+ than the ethylene diamine derivative, indicating that the presence of an alkyl chain in the diamine decreases the sensitivity of the receptors towards Sn2+. The presence of carbonyl groups and terminal amino groups strongly influences the sensitivity of the chemosensors toward Sn2+ by a spirolactam ring-opening mechanism. The receptors exhibit 1:1 complexation with Sn2+ as evidenced by Job plot, and the corresponding limit of detection was found to be 1.62 × 10−7 M. The fluorescence images of the receptors and their complexes reveal their potential applications for imaging of Sn2+ in real/online samples

Fluorescent “OFF–ON” Sensors for the Detection of Sn2+ Ions Based on Amine-Functionalized Rhodamine 6G

These structurally isomeric rhodamine 6G-based amino derivatives are designed to detect Sn2+ ions. The receptors exhibit rapid fluorescent “turn-on” responses towards Sn2+. The absorption (530 nm) and fluorescent intensity (551 nm) of the receptors increase when increasing the concentration of Sn2+. The hydrazine derivative exhibits more rapid sensitivity towards Sn2+ than the ethylene diamine derivative, indicating that the presence of an alkyl chain in the diamine decreases the sensitivity of the receptors towards Sn2+. The presence of carbonyl groups and terminal amino groups strongly influences the sensitivity of the chemosensors toward Sn2+ by a spirolactam ring-opening mechanism. The receptors exhibit 1:1 complexation with Sn2+ as evidenced by Job plot, and the corresponding limit of detection was found to be 1.62 × 10−7 M. The fluorescence images of the receptors and their complexes reveal their potential applications for imaging of Sn2+ in real/online samples

Ultrasonic mediated dual-site phase transfer catalyzed polymerization of N-butenyl isatin in two phase system- a kinetic study

Use of ultrasound as an additional source for promoting polymerization reactions has gained great attention. Phase transfer catalyst (PTC) along with ultrasonication in polymerization process is an attractive methodology to achieve good yield and realizing principles of green chemistry. Herein, we reported the facile polymerization of synthesized novel N-butenyl isatin (NBI) at 60 ± 2 °C with and without ultrasonic irradiation (45 kHz; 550 W) using dual-site phase transfer catalyst (1, 4-bis (triethyl methyl ammonium) benzene dibromide, TEMABDB) and potassium peroxydisulphate (PDS or PPS) as initiator. Ultrasonication (US) promotes the formation of reactive radicals, which can be utilized effectively in phase transfer polymerization process. Hence, the rate was multi-folded (twice) in comparison with silent condition. The effect of sonication frequency and various reaction parameters on the polymerization process were investigated in both conditions. An enhancement of reaction rate under sonication was validated by activation parameter. Synthesized monomer and poly (N-butenyl isatin) was characterized by different spectral methods. Facile polymerization of N-butenyl isatin by sonication aided dual-site PTC. Green approach and mild conditions used for polymerization of NBI. Sonication lifts the rate significantly in comparison with standard condition. Effects of variables in polymerization rate were explored in both conditions. Poly (N-butenyl isatin) was analyzed by different spectral techniques.</p

Solution, Solid State, and Film Properties of a Structurally Characterized Highly Luminescent Molecular Europium Plastic Material Excitable with Visible Light

International audienceThe synthesis and X-ray crystal structure of the ligand L (4,7-dicarbazol-9-yl-[1,10]-phenanthroline) are reported, as well as those of the molecular complex, [Eu(tta)3(L)] (1), (tta = 2-thenoyl trifluoroacetylacetonate). Their photophysical properties have been investigated both in solution and in the solid state. It was shown that the ligands used for designing 1 are well-suited for sensitizing the EuIII ion emission, thanks to a favorable position of the triplet state as investigated in the GdIII complex [Gd(tta)3(L)], (2). The low local symmetry of the EuIII ion shown by the X-ray crystal structure of 1 is also revealed by luminescence spectroscopy. Because of interesting volatility and solubility properties, 1 is shown to behave as a real molecular material that can be processed both by thermal evaporation and from solution. When doped in poly(methylmethacrylate) (PMMA), 1 forms air-stable and highly red-emitting plastic materials that can be excited in a wide range of wavelengths from the UV to the visible part of the electromagnetic spectrum (250-560 nm). Absolute quantum yields of 80% have been obtained for films comprising 1-3% of 1. Ellipsometry measurements have been introduced to gain information on physical data of 1. They have been performed on thin films of 1 deposited by thermal evaporation and gave access to the refractive index, n, and the absorption coefficient, k, as a function of the wavelength. A value of 1.70 has been found for n at 633 nm. These thin films also show interesting air-stability