Facile synthesis of diiodoheteroindenes and understanding their Sonogashira cross-coupling selectivity for the construction of unsymmetrical enediynes.

Electrophile-promoted cyclizations of functionalized alkynes offer a useful tool for constructing halogen-substituted heterocycles primed for further derivatization. Preinstallation of an iodo-substituent at the alkyne prior to iodo-cyclization opens access to di-iodinated heterocyclic precursors for the preparation of unsymmetrical heterocycle-fused enediynes. This general approach was used to prepare 2,3-diiodobenzothiophene, 2,3-diiodoindole, and 2,3-diiodobenzofuran, a useful family of substrates for systematic studies of the role of heteroatoms on the regioselectivity of cross-coupling reactions.

Development of Fluorescent Isocoumarin-Fused Oxacyclononyne - 1,2,3-Triazole Pairs.

Fluorescent isocoumarin-fused cycloalkynes, which are reactive in SPAAC and give fluorescent triazoles regardless of the azide nature, have been developed. The key structural feature that converts the non-fluorescent cycloalkyne/triazole pair to its fluorescent counterpart is the pi-acceptor group (COOMe, CN) at the C6 position of the isocoumarin ring. The design of the fluorescent cycloalkyne/triazole pairs is based on the theoretical study of the S1 state deactivation mechanism of the non-fluorescent isocoumarin-fused cycloalkyne IC9O using multi-configurational ab initio and DFT methodologies.

Heterometallic Europium(III)-Lutetium(III) Terephthalates as Bright Luminescent Antenna MOFs.

A new series of luminescent heterometallic europium(III)-lutetium(III) terephthalate metal-organic frameworks, namely (EuLu)bdc·nHO, was synthesized using a direct reaction in a water solution. At the Eu concentration of 1-40 at %, the MOFs were formed as a binary mixture of the (EuLu)bdc and (EuLu)bdc·4HO crystalline phases, where the Lnbdc·4HO crystalline phase was enriched by europium(III) ions. At an Eu concentration of more than 40 at %, only one crystalline phase was formed: (EuLu)bdc·4HO.

Ultrasound-Assisted Synthesis of Luminescent Micro- and Nanocrystalline Eu-Based MOFs as Luminescent Probes for Heavy Metal Ions.

The luminescent coarse-, micro- and nanocrystalline europium(III) terephthalate tetrahydrate (Eubdc·4HO) metal-organic frameworks were synthesized by the ultrasound-assisted wet-chemical method. Electron micrographs show that the europium(III) terephthalate microparticles are 7 μm long leaf-like plates. According to the dynamic light scattering technique, the average size of the Eubdc·4HO nanoparticles is equal to about 8 ± 2 nm.

Gd-Doping Effect on Upconversion Emission of NaYF: Yb, Er/Tm Microparticles.

β-NaYF microcrystals co-doped with Yb, Er/Tm, and Gd ions were synthesized via a hydrothermal method using rare-earth chlorides as the precursors. The SEM and XRD data show that the doped β-NaYF form uniform hexagonal prisms with an approximate size of 600-800 nm. The partial substitution of Y by Gd results in size reduction of microcrystals.

Reductive and Coordinative Effects of Hydrazine in Structural Transformations of Copper Hydroxide Nanoparticles.

Shape-specific copper oxide nanostructures have attracted increasing attention due to their widespread applications in energy conversion, sensing, and catalysis. Advancing our understanding of structure, composition, and surface chemistry transformations in shaped copper oxide nanomaterials during changes in copper oxidation state is instrumental from both applications and preparative nanochemistry standpoints. Here, we report the study of structural and compositional evolution of amorphous copper (II) hydroxide nanoparticles under hydrazine reduction conditions that resulted in the formation of crystalline CuO and composite CuO-NH branched particles.