A microwave-assisted method for the preparation of a wide color range of 2,3,3-trimethylindolenine-based squaraines and their intermediates is described. This practical approach allows the rapid preparation of both symmetrical and nonsymmetrical squaraine dyes, reducing reaction time from days to minutes with more than 2-fold improvement in product yields when compared to conventional methods.
We report on the design, fabrication, and characterization of optical sensors based on Bloch surface waves propagating at the truncation edge of one-dimensional photonic crystals. The sensors can be simultaneously operated in both a label-free mode, where small refractive index changes at the surface are detected, and a fluorescence mode, where the fluorescence from a novel heptamethyne dye label in the proximity of the surface is collected. The two modes operate in the near-infrared spectral range with the same configuration of the optical reading apparatus. The limit of detection is shown to be smaller than that of equivalent surface plasmon sensors and the fluorescence collection efficiency is such that it can be efficiently analyzed by the same camera sensor used for label-free operation.
Imidazolium based porous cationic polymers were synthesized using an innovative and facile approach, which takes advantage of the Debus-Radziszewski reaction to obtain meso-/microporous polymers following click-chemistry principles. In the obtained set of materials, click based-porous cationic polymers have the same cationic backbone whereas they bear the commonly used anions of imidazolium poly(ionic liquid)s. These materials show hierarchical porosity and good specific surface area. Furthermore, their chemical structure was extensively characterized using ATR-FTIR and SS-NMR spectroscopies, and HR-MS. These polymers show good performance towards carbon dioxide sorption, especially those possessing the acetate anion. This polymer can uptake 2 mmol/g of CO2 at 1 bar and 273 K, a value which is among the highest recorded for imidazolium poly(ionic liquid)s. These polymers were also modified in order to introduce N-heterocyclic carbene along the backbone. Carbon dioxide loading in the carbene containing polymer is in the same range of the non-modified versions, but the nature of the interaction is substantially different. Combined use of in-situ FTIR spectroscopy and micro-calorimetry evidenced a chemisorption phenomenon that brings to the formation of an imidazolium carboxylate zwitterion
Terpyridine and quaterpyridine-based complexes allow wide light harvesting of the solar spectrum. Terpyridines, with respect to bipyridines, allow for achieving metal-complexes with lower band gaps in the metal-to-ligand transition (MLCT), thus providing a better absorption at lower energy wavelengths resulting in an enhancement of the solar light-harvesting ability. Despite the wider absorption of the first tricarboxylate terpyridyl ligand-based complex, Black Dye (BD), dye-sensitized solar cell (DSC) performances are lower if compared with N719 or other optimized bipyridine-based complexes. To further improve BD performances several modifications have been carried out in recent years affecting each component of the complexes: terpyridines have been replaced by quaterpyridines; other metals were used instead of ruthenium, and thiocyanates have been replaced by different pinchers in order to achieve cyclometalated or heteroleptic complexes. The review provides a summary on design strategies, main synthetic routes, optical and photovoltaic properties of terpyridine and quaterpyridine ligands applied to photovoltaic, and focuses on n-type DSCs.
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