RESUMO
Near-infrared (NIR) fluorophores have promoted the development of materials for bioimaging, but traditional NIR dyes usually suffer from aggregation-caused quenching (ACQ), impeding their applications. Herein, we propose two difluoroboron ß-diketonate complexes TBO and TBS, consisting a donor-acceptor (D-A) structure with triphenylamine (TPA) moiety as an electron donors and difluoroboron as well as furan or thiophene building block as an electron acceptor. The theoretical calculation and optical data shows that both of them have intramolecular charge transfer (ICT) characteristics. Such ICT characteristics endow them with both solvatochromism and dual-state emission (DSE) properties. In the solvent CH2Cl2, the emission wavelength of TBO ranges from 550 nm to 750 nm, with a low fluorescence quantum yield (Φ = 7.0 %). However, in the less polar solvent hexane, the emission wavelength blue-shifts, with an increased Φ reaching up to 18 %. Moreover, TBO and TBS exhibit mechanochromic characteristics and rare multi-channel fluorescence emission phenomena at solid-state. Their solid-state samples can emit fluorescence in four spectral bands with maximum emission wavelengths at 300 nm, 400 nm, 600 nm, and 770 nm under excitation at 240 nm. These unique optical properties are expected to be utilized for detecting polarity of system and deformation. Moreover, according to the results of cell imaging and flow cytometry, TBO molecular were easily internalized into Hela cells and distributed in the cytoplasm with strong red fluorescence. Therefore, this research inspires more insight into development of NIR luminogens for biomedical imaging.
RESUMO
In this work, ionic liquid (IL) of 1-propyl-3-methyl imidazolium chloride-functionalized silica-mesostructured cellular foam (MCF) was prepared. The obtained MCF-IL was used to construct the Fe(CN)63--confined electrode (MCF-IL-Fe(CN)63-/PVA) and H2O2 electrochemical behavior on the electrode was investigated. It was found that H2O2 was oxidized on the freshly prepared electrode while catalytically electro-reduced on the acid pretreated one. Cyclic voltametric results revealed that the real catalyst for catalytic reduction of H2O2 was Prussian blue (PB) rather than Fe(CN)63-. The electrocatalytic ability of the acid-pretreated MCF-IL-Fe(CN)63-/PVA electrode offered a wide linear range for H2O2 detection. The present study on H2O2 electrochemical behavior on an MCF-IL-Fe(CN)63-/PVA electrode might provide useful information for further developing integrated Fe(CN)63--mediated biosensors as H2O2 is extensively involved in the classic reaction containing oxidase enzymes.