High quantum yield boron-doped carbon dots: a ratiometric fluorescent probe for highly selective and sensitive detection of Mg2+ ions

Highly fluorescent boron-doped carbon dots were synthesized from catechol and naphthalene boronic acid by a solvothermal method. They showed violet luminescence under UV illumination and were explored for highly selective detection of Mg2+ ions, with an LOD of ~39 μM.

Synthesis, crystal structure, and photoluminescence of a lithium isothiocyanate compound with 18-crown-6

The investigation of the supramolecular interactions between the lithium isothiocyanate salt and 18-crown-6 (18C-6) in commercial tetrahydrofuran leads to the formation of a lithium compound, LiNCS(H2O)(18C-6) (1). In the crystal structure the asymmetric unit contains two similar LiNCS(H2O)(18C-6) molecules. Solid-state photoluminescence experiments have shown that compound 1 emits violet luminescence, and its possible emission mechanism was investigated in detail based on theoretical calculations.

Sr1/2Ce5/14□1/7WO4: a new modulated ternary scheelite compound

For the first time, a ternary tetragonal scheelite structure tungstate with strontium and cerium cations, (Sr,Ce)WO4, was synthesized. As much as 35% Ce could be inserted into the structure, leaving 1\over 7 of the (Sr,Ce) cation sites vacant. Partial ordering of Sr and Ce, with atomic displacements, were shown by high-resolution electron microscopy. Two-dimensional incommensurate modulations occur in this material, in small domains 20 nm in size. The band gap of this compound is significantly lower than the band gap of SrWO4and this was related to the distortions of WO4and (Sr,Ce)O8polyhedra. The band gap value of 3.2 eV makes Sr1/2Ce5/14□1/7WO4a promising candidate for violet luminescence.

Synthesis, crystal structure, and photoluminescence of a dumbbell-like sodium dicyanamide compound with 15-crown-5

Gaseous diffusion of n-hexane into the reaction mixture of sodium dicyanamide NaN(CN)2 with 15-crown-5 in tetrahydrofuran leads to a sodium dicyanamide compound [Na(15-crown-5)]N(CN)2 (1). Compound 1 exhibits a centrosymmetric dumbbell-like structure constructed by dicyanamide ligands double-bridging [Na(15-crown-5)]+ moieties with a μ-1,5 coordination mode. Solid-state photoluminescence experiments have shown that compound 1 emits violet luminescence, and its possible emission mechanism was investigated in detail based on theoretical calculations.

syn-BN-heteroacene cored conjugated oligomers with finely tuned blue-violet luminescent properties

Starting from dibrominated syn-BN-heteroacenes, a series of BN-containing conjugated oligomers with blue-violet luminescence was synthesized.

Feathery and network-like filamentous textures as indicators for the re-crystallization of quartz from a metastable silica precursor at the Rusey Fault Zone, Cornwall, UK

Hydrothermal quartz crystals, which occur in the Rusey Fault Zone (Cornwall, UK), show feathery textures and network-like filamentous textures. Optical hot-cathodoluminescence (CL) analysis and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) investigations on quartz samples revealed that positions exhibiting feathery textures (violet luminescence) contain higher amounts of Al and Li than quartz positions without feathery textures (blue luminescence), while concentrations of Al and Li are significantly lower in feathery textures. Both Al and Li correlate negatively with Si. Raman spectroscopy investigations revealed the presence of a weak peak at 507–509 cm−1 in quartz affected by feathery textures, which we attribute to the presence of ≤ 5 % moganite, a microcrystalline silica polymorph, intergrown with chalcedony. The combined occurrence of feathery textures and network-like filamentous textures in quartz samples from the Rusey Fault Zone points to the presence of a metastable silica precursor (i.e., amorphous silica or silica gel) before or during the crystallization.