Synthesis, crystal structure, hirshfeld surface analysis, DFT calculations and thermal properties of a new anilinium derivative chlorostannate(IV) hybrid compound

Evidence and Practical Applications of Site Occupancy Theory (SOT) of Eu3+ in Scheelite Compounds

The determination of the site occupancy of activators in phosphors is essential for precise synthesis, understanding the relationship between their luminescence properties and crystal structure, and tailoring their properties by modifying the host composition. Herein, one simple method was proposed to help determine the sites at which the doping of rare earth ions or transition metal ions occupies in the host lattice through site occupancy theory (SOT) for ions doped into the matrix lattice. SOT was established based on the fact that doping ions preferentially occupy the sites with the lowest bonding energy deviations. In order to provide detailed experimental evidence to prove the feasibility of SOT, several scheelite-type compounds were successfully synthesized using a high-temperature solid-phase method. When Eu3+ ions occupy a similar surrounding environment site, the photoluminescence spectra of the activators Eu3+ are similar. Therefore, by comparing the intensity ratio of photoluminescence spectra and the mechanism of all transitions of KEu(WO4)2, KY(WO4)2:Eu3+, Na5Eu(WO4)4, and Na5Y(WO4)4:Eu3+, it was proved that SOT can successfully confirm the site occupation when doped ions enter the matrix lattice. SOT was further applied to the sites occupied by Eu3+ ion-doped LiAl(MoO4)2 and LiLu(MoO4)2.

Brush-like Polyaniline with Optical and Electroactive Properties at Neutral pH and High Temperature

In this research, a brush-like polyaniline (poly(2-acrylamide-2-methyl-1-propanesulfonate)-g-polyaniline)-b-poly(N-vinylcarbazole) (BL PAni) was developed as a strategy to overcome the limited processability and dedoping above pH 4 of conventional polyaniline (PAni). For the BL PAni synthesis, RAFT polymerization (homopolymer), RAFT-mediated surfactant-free emulsion polymerization (block copolymer), and interfacial oxidative polymerization were applied to graft the PAni chains. NMR and FT-IR spectroscopies were performed to confirm the structural elucidation of the reaction pathways, while the thermal properties were analyzed by TGA and DSC. Notably, the BL PAni presents absorption throughout the visible region and up to the near-infrared, showing dedoping resistance at up to 80 °C and at a neutral pH. The absorption range of the BL PAni, block copolymer, and homopolymer were studied by UV–Vis spectroscopy in solid-state and dispersion/solution, highlighting BL PAni and poly(anilinium 2-acrylamide-2-methyl-1-propanesulfonate)-b-poly(N-vinylcarbazole) (PAAMP-b-PVK) due to the π-stacking between the anilinium and carbazole groups. The cyclic voltammetry confirmed the persistence of electroactivity at a pH near 7.