Homogeneously Alloyed CdSe_1–<i>x</i>S_<i>x</i> Quantum Dots (0 ≤ <i>x</i> ≤ 1): An Efficient Synthesis for Full Optical Tunability

Homogeneously Alloyed CdSe_1–<i>x</i>S_<i>x</i> Quantum Dots (0 ≤ <i>x</i> ≤ 1): An Efficient Synthesis for Full Optical Tunabilit

Speciation of Copper(II) Complexes in an Ionic Liquid Based on Choline Chloride and in Choline Chloride/Water Mixtures

A deep-eutectic solvent with the properties of an ionic liquid is formed when choline chloride is mixed with copper­(II) chloride dihydrate in a 1:2 molar ratio. EXAFS and UV–vis–near-IR optical absorption spectroscopy have been used to compare the coordination sphere of the cupric ion in this ionic liquid with that of the cupric ion in solutions of 0.1 M of CuCl₂·2H₂O in solvents with varying molar ratios of choline chloride and water. The EXAFS data show that species with three chloride ions and one water molecule coordinated to the cupric ion as well as species with two chloride molecules and two water molecules coordinated to the cupric ion are present in the ionic liquid. On the other hand, a fully hydrated copper­(II) ion is formed in an aqueous solution free of choline chloride, and the tetrachlorocuprate­(II) complex forms in aqueous choline chloride solutions with more than 50 wt % of choline chloride. In solutions with between 0 and 50 wt % of choline chloride, mixed chloro–aquo complexes occur. Upon standing at room temperature, crystals of CuCl₂·2H₂O and of Cu­(choline)­Cl₃ formed in the ionic liquid. Cu­(choline)­Cl₃ is the first example of a choline cation coordinating to a transition-metal ion. Crystals of [choline]₃[CuCl₄]­[Cl] and of [choline]₄[Cu₄Cl₁₀O] were also synthesized from molecular or ionic liquid solvents, and their crystal structures were determined

Mouchet et al., 2016, Proc. R. Soc. B, Primary Data

Reflectance spectra; Excitation spectra; Emission spectra; Time-resolved Fluorescence Intensity - Further information: see related article

Speciation of Copper(II) Complexes in an Ionic Liquid Based on Choline Chloride and in Choline Chloride/Water Mixtures

A deep-eutectic solvent with the properties of an ionic liquid is formed when choline chloride is mixed with copper­(II) chloride dihydrate in a 1:2 molar ratio. EXAFS and UV–vis–near-IR optical absorption spectroscopy have been used to compare the coordination sphere of the cupric ion in this ionic liquid with that of the cupric ion in solutions of 0.1 M of CuCl₂·2H₂O in solvents with varying molar ratios of choline chloride and water. The EXAFS data show that species with three chloride ions and one water molecule coordinated to the cupric ion as well as species with two chloride molecules and two water molecules coordinated to the cupric ion are present in the ionic liquid. On the other hand, a fully hydrated copper­(II) ion is formed in an aqueous solution free of choline chloride, and the tetrachlorocuprate­(II) complex forms in aqueous choline chloride solutions with more than 50 wt % of choline chloride. In solutions with between 0 and 50 wt % of choline chloride, mixed chloro–aquo complexes occur. Upon standing at room temperature, crystals of CuCl₂·2H₂O and of Cu­(choline)­Cl₃ formed in the ionic liquid. Cu­(choline)­Cl₃ is the first example of a choline cation coordinating to a transition-metal ion. Crystals of [choline]₃[CuCl₄]­[Cl] and of [choline]₄[Cu₄Cl₁₀O] were also synthesized from molecular or ionic liquid solvents, and their crystal structures were determined

Speciation of Copper(II) Complexes in an Ionic Liquid Based on Choline Chloride and in Choline Chloride/Water Mixtures

A deep-eutectic solvent with the properties of an ionic liquid is formed when choline chloride is mixed with copper­(II) chloride dihydrate in a 1:2 molar ratio. EXAFS and UV–vis–near-IR optical absorption spectroscopy have been used to compare the coordination sphere of the cupric ion in this ionic liquid with that of the cupric ion in solutions of 0.1 M of CuCl₂·2H₂O in solvents with varying molar ratios of choline chloride and water. The EXAFS data show that species with three chloride ions and one water molecule coordinated to the cupric ion as well as species with two chloride molecules and two water molecules coordinated to the cupric ion are present in the ionic liquid. On the other hand, a fully hydrated copper­(II) ion is formed in an aqueous solution free of choline chloride, and the tetrachlorocuprate­(II) complex forms in aqueous choline chloride solutions with more than 50 wt % of choline chloride. In solutions with between 0 and 50 wt % of choline chloride, mixed chloro–aquo complexes occur. Upon standing at room temperature, crystals of CuCl₂·2H₂O and of Cu­(choline)­Cl₃ formed in the ionic liquid. Cu­(choline)­Cl₃ is the first example of a choline cation coordinating to a transition-metal ion. Crystals of [choline]₃[CuCl₄]­[Cl] and of [choline]₄[Cu₄Cl₁₀O] were also synthesized from molecular or ionic liquid solvents, and their crystal structures were determined

Bright and Stable CdSe/CdS@SiO₂ Nanoparticles Suitable for Long-Term Cell Labeling

We report on the synthesis of luminescent CdSe/CdS@SiO₂ nanoparticles and their application to cell labeling. The main novelty of these nanoparticles is the use of newly developed “flash” CdSe/CdS quantum dots (QDs), which are obtained through a new fast and efficient synthesis method recently reported. These core–shell QDs are encapsulated in silica nanoparticles through a water-in-oil microemulsion process, resulting in CdSe/CdS@SiO₂ nanoparticles with good morphology and controlled architecture. The main asset of these luminescent nanoparticles is their high photoluminescent quantum yield, which is equal to that of the original CdSe/CdS QDs and remains unchanged even after several months of storage in water. Thanks to the remarkable stability of their optical property in aqueous environment and to their low levels of toxicity, the high potential of these nanoparticles for long-term cell labeling is demonstrated

Synthesis, Crystal Structures, and Luminescence Properties of Carboxylate Based Rare-Earth Coordination Polymers

Rare-earth coordination polymers or lanthanide–organic frameworks with hitherto unreported crystal structures have been obtained on the basis of the “light” lanthanides Pr, Nd, Sm, and Eu in combination with terephthalic acid and using a slightly altered literature synthesis procedure. Rietveld refinement has shown that powder XRD patterns of such compounds are largely dominated by the positions of the heavy elements, pointing to isostructural networks for all four terephthalate-based materials. An in-depth luminescence study has been performed on the reported MOFs, showing rare praseodymium and samarium emission in the visible spectrum, aside from the strong europium luminescence and the near-infrared emission from both a terephthalate and 2,5-pyridinedicarboxylate based neodymium-MOF

Controlled fluorescence in a beetle's photonic structure and its sensitivity to environmentally induced changes, Mouchet et al. Controlled fluorescence in a beetle's photonic structure and its sensitivity to environmentally induced changes

Supplementary materia

“Flash” Synthesis of CdSe/CdS Core–Shell Quantum Dots

We report on the “flash” synthesis of CdSe/CdS core–shell quantum dots (QDs). This new method, based on a seeded growth approach and using an excess of a carboxylic acid, leads to an isotropic and epitaxial growth of a CdS shell on a wurtzite CdSe core. The method is particularly fast and efficient, allowing the controllable growth of very thick CdS shells (up to 6.7 nm in the present study) in no more than 3 min, which is considerably shorter than in previously reported methods. The prepared materials present state-of-the-art properties with narrow emission and high photoluminescence quantum yields, even for thick CdS shells. Additionally, Raman analyses point to an alloyed interface between the core and the shell, which, in conjunction with the thickness of the CdS shell, results in the observed considerable reduction of the blinking rate

Bipyridine-Based Nanosized Metal–Organic Framework with Tunable Luminescence by a Postmodification with Eu(III): An Experimental and Theoretical Study

A gallium 2,2′-bipyridine-5,5′-dicarboxylate metal–organic framework, Ga­(OH)­(bpydc), denoted as COMOC-4 (COMOC = Center for Ordered Materials, Organometallics and Catalysis, Ghent University) has been synthesized via solvothermal synthesis procedure. The structure has the topology of an aluminum 2,2′-bipyridine-5,5′-dicarboxylate – the so-called MOF-253. TEM and SEM micrographs show the COMOC-4 crystals are formed in nanoplates with uniform size of 30–50 nm. The UV–vis spectra of COMOC-4 in methanol solution show maximal electronic absorption at 307 nm. This results from linker to linker transitions as elucidated by time-dependent density functional theory simulations on the linker and COMOC-4 cluster models. When excited at 400 nm, COMOC-4 displays an emission band centered at 542 nm. Upon immersion in different solvents, the emission band for the framework is shifted in the range of 525–548 nm depending on the solvent. After incorporating Eu³⁺ cations, the emission band of the framework is shifted to even shorter wavelengths (505 nm). By varying the excitation wavelengths from 250 to 400 nm, we can fine-tune the emission from red to yellowish green in the CIE diagram. The luminescence behavior of Eu³⁺ cations is well preserved and the solid-state luminescence lifetimes of τ₁ = 45 μs (35.4%) and τ₂ = 162 μs (64.6%) are observed