New cyano functionalized silanes: Synthesis, characterization and diphenylamine detection

Tetrahedral Silicon-Centered Dibenzoylmethanatoboron Difluorides: Synthesis, Crystal Structure, and Photophysical Behavior in Solution and the Solid State

Four tetrahedral silicon-centered derivatives of dibenzoylmethanatoboron difluoride (DBMBF₂ ) were synthesized and characterized. Their structural and optical features both in solution and the solid state were investigated by using X-ray crystallography, steady-state and time-dependent spectroscopy, and DFT-based calculations. In dilute solutions, the molar absorption coefficient increases from 40500 to 175200 M^-1  cm^-1 as the number of DBMBF₂ fragments in a molecule increases from one to four, while, in contrast, the nonradiative rate constant of fluorescence decay decreases from 0.49 to 0.34. In the solid state, absorption and emission spectra depend on the degree of crystallinity and microcrystal size. The tris-DBMBF₂ derivative forms fully overlapping dimeric structures that exhibit excimer-like fluorescence, which is accurately predicted by the quantum-chemical calculations. The mono-DBMBF₂ derivative exhibits fully reverse mechanofluorochromic behavior.

BSA-AuNPs@Tb-AMP metal-organic frameworks for ratiometric fluorescence detection of DPA and Hg2

An easy and effective strategy for synthesizing a ratiometric fluorescent nanosensor has been demonstrated in this work. Novel fluorescent BSA-AuNPs@Tb-AMP (BSA, bovine serum albumin; AMP, adenosine 5'-monophosphate; AuNPs, Au nanoparticles) metal-organic framework (MOF) nanostructures were synthesized by encapsulating BSA-AuNPs into Tb-AMP MOFs for the detection of 2,6-pyridinedicarboxylic acid (DPA) and Hg²⁺ . DPA could strongly co-ordinate with Tb³⁺ to replace water molecules from the Tb³⁺ center and accordingly enhanced the fluorescence of Tb-AMP MOFs. The fluorescence of BSA-AuNPs at 405 nm remained constant. While the fluorescence of BSA-AuNPs at 635 nm was quenched after Hg²⁺ was added, the fluorescence of Tb-AMP MOFs remained constant. Accordingly, a ratiometric fluorescence nanosensor was constructed for detection of DPA and Hg²⁺ . The ratiometric nanosensor exhibited good selectivity to DPA over other substances. The F₅₄₅ /F₄₀₅ linearly increased with increase of DPA concentration in the range of 50 nM to 10 μM with a detection limit as low as 17.4 nM. F₆₃₅ /F₄₀₅ increased linearly with increase of Hg²⁺ concentration ranging from 50 nM to 1 μM with a detection limit as low as 20.9 nM. Additionally, the nanosensor could be successfully applied for the determination of DPA and Hg²⁺ in running water.

Preparation and characterization of room temperature vulcanized silicone rubber using α-amine ketoximesilanes as auto-catalyzed cross-linkers

A series of α-amine ketoximesilanes were prepared and used as auto-catalyzed cross-linkers in one component room temperature vulcanized (RTV) silicone rubber.