Copper-Catalyzed Cascade Multicomponent Reaction of Azides, Alkynes, and Selenium: Synthesis of Ditriazolyl Diselenides.

A copper-catalyzed cascade multicomponent reaction for synthesizing ditriazolyl diselenides from azides, terminal alkynes, and elemental selenium has been developed. The present reaction features utilizing readily available and stable reagents, high atom-economy, and mild reaction conditions. A possible mechanism is proposed.

Oxidative Dehydrogenative Coupling of Thiols with Alkanes for the Synthesis of Sulfoxides.

An oxidative dehydrogenative coupling of thiols with alkanes via direct C(sp3)-H bond functionalization to form a new C-S bond and S═O double bond was developed. The present reaction features the use of readily available reagents and high step- and atom-efficiency, thus providing an efficient access to sulfoxides. A possible mechanism is proposed.

Highly efficient and air-stable Eu(II)-containing azacryptates ready for organic light-emitting diodes.

Divalent europium 5d-4f transition has aroused great attention in many fields, in a way of doping Eu2+ ions into inorganic solids. However, molecular Eu2+ complexes with 5d-4f transition are thought to be too air-unstable to explore their applications. In this work, we synthesized four Eu2+-containing azacryptates EuX2-Nn (X = Br, I, n = 4, 8) and systematically studied the photophysical properties in crystalline samples and solutions. Intriguingly, the EuX2-N8 complexes exhibit near-unity photoluminescence quantum yield, good air-/thermal-stability and mechanochromic property (X = I). Furthermore, we proved the application of Eu2+ complexes in organic light-emitting diodes (OLEDs) with high efficiency and luminance. The optimized device employing EuI2-N8 as emitter has the best performance as the maximum luminance, current efficiency, and external quantum efficiency up to 25470 cd m-2, 62.4 cd A-1, and 17.7%, respectively. Our work deepens the understanding of structure-property relationship in molecular Eu2+ complexes and could inspire further research on application in OLEDs.

Self-Repairing Tin-Based Perovskite Solar Cells with a Breakthrough Efficiency Over 11.

The development of tin (Sn)-based perovskite solar cells (PSCs) is hindered by their lower power conversion efficiency and poorer stability compared to the lead-based ones, which arise from the easy oxidation of Sn2+ to Sn4+ . Herein, phenylhydrazine hydrochloride (PHCl) is introduced into FASnI3 (FA = NH2 CH  NH2 + ) perovskite films to reduce the existing Sn4+ and prevent the further degradation of FASnI3 , since PHCl has a reductive hydrazino group and a hydrophobic phenyl group. Consequently, the device achieves a record power conversion efficiency of 11.4% for lead-free PSCs. Besides, the unencapsulated device displays almost no efficiency reduction in a glove box over 110 days and shows efficiency recovery after being exposed to air, due to a proposed self-repairing trap state passivation process.

A Family of Highly Emissive Lanthanide Complexes Constructed with 6-(Diphenylphosphoryl)picolinate.

We report a novel family of lanthanide complexes Ln(DPPOP)3 (Ln = Pr, Nd, Sm, Eu, Tb, Dy, Er, and Yb) employing anionic tridentate (O∧N∧O) ligand 6-(diphenylphosphoryl)picolinate (DPPOP). Crystal structures of the complexes reveal that each lanthanide ion is nine-coordinated by three tridentate ligands. In the crystals, 1D channels are found, which can absorb and eliminate water reversibly. DPPOP possesses high triplet energy and can sensitize a series of lanthanide ions. An energy transfer mechanism is proposed through the higher excited states of the lanthanide ions. In the solid state, remarkably high quantum yields in the visible range are obtained: 81% for Eu(III), 97% for Tb(III), 13% for Dy(III), and 4% for Sm(III) complex.

Correction: Highly efficient room-temperature phosphorescence achieved by gadolinium complexes.

Correction for 'Highly efficient room-temperature phosphorescence achieved by gadolinium complexes' by Boxun Sun et al., Dalton Trans., 2019, 48, 14958-14961.

Highly efficient room-temperature phosphorescence achieved by gadolinium complexes.

A new family of room temperature phosphorescent materials with emission lifetimes in microseconds has been reported in this work. Phosphorescence of gadolinium complexes with emission color from blue to orange has been obtained at room temperature with a maximum photoluminescence quantum yield of 66%, benefiting from appropriate molecular structures and favorable encapsulation methods.

Quantum Yields over 80% Achieved in Luminescent Europium Complexes by Employing Diphenylphosphoryl Tridentate Ligands.

Four tridentate europium(III) complexes containing a diphenylphosphoryl group are prepared with strong bonding between the ligands and centered ion, convinced by crystal structures. Compared to their parent bidentate complexes, the tridentate complexes display improved and exceptionally high photoluminescence quantum yields (PLQYs) in powder (all over 80%, best 91%), as well as in a CH2Cl2 solution and poly(methyl methacrylate) films, benefiting from compact, stable, and saturated coordination.

Water-Soluble and Highly Luminescent Europium(III) Complexes with Favorable Photostability and Sensitive pH Response Behavior.

Two highly luminescent and water-soluble Eu(III) complexes, Eu1 and Eu2, based on novel carboxyl-functionalized 1,5-naphthyridine derivatives 8-hydroxy-1,5-naphthyridine-2-carboxylic acid (H2L1) and 7-cyano-8-hydroxy-1,5-naphthyridine-2-carboxylic acid (H2L2), respectively, are designed and synthesized. The crystal structure of Eu2 indicates that the central Eu(III) ion is nine-coordinated by three tridentate ligands (O^N^O). Both Eu1 and Eu2 show strong luminescence in aqueous solution with quantum yields (lifetimes) of 28% (1.1 ms) and 14% (0.76 ms), respectively. The chelates display unique UV-light stability in solution and remain highly emissive after 100 min of strong UV irradiation (∼300 W·m-2 at 345 nm). Moreover, they exhibit reversible luminescence intensity changes with varied pH values, and the response mechanism is investigated. "Turn-on" of the Eu(III) emission upon increasing pH is realized by ligand structure change from keto to enol anion form, resulting in red-shifted absorption band and suppressed quenching from solvents and N-H vibration upon deprotonating. The results show that these novel Eu(III) complexes are quite intriguing for potential application as bioimaging agents and pH probes.