Hoseop Yun

Organic terahertz (THz) crystals exhibit complex and often unpredictable relationships among their chemical structures, crystal structures, and physical properties. This complexity makes it highly challenging to optimize crystals for efficient THz generation. Here, we introduce a design strategy based on isomorphic ionic organic crystal families to develop new organic nonlinear optical crystals that efficiently generate ultra-broadband THz waves extending up to 15 THz. Using three nonlinear optical cationic chromophores with different interionic assembly types, each combined with three molecular anions featuring different substituents (non-polar methyl or polar chloro and bromo groups), we investigated nine ionic crystals, including four reported here for the first time. The crystal members within each isomorphic crystal family show nearly identical crystal structures (i.e., isomorphic crystal structures), all of them achieving top-level macroscopic second-order optical nonlinearity and efficient ultrabroad THz wave generation capabilities. Remarkably, their physical (and terahertz) properties within each isomorphic crystal family differ dramatically according to a certain order of the introduced anions, and this ordering trend persists across all three isomorphic crystal families. These results provide a crucial advancement in the design and prediction of macroscopic properties in ionic organic THz and nonlinear optical crystals, marking an important step toward rational crystal design exhibiting enhanced physical properties.

Organic–inorganic copper(I) halide complexes have attracted attention due to their optoelectronic properties and non‐toxic nature. In this study, we systematically synthesized copper(I) halide melamine complexes as single crystals, (CuBr(melamine) and CuI(melamine)) and polycrystalline powders, CuBr_xI_1‐x(melamine) (0 ≤ x ≤ 1). The crystal structures of CuBr(melamine) and CuI(melamine) are isotypic with a triclinic space group P , where copper(I) is connected with three adjacent halides along the a‐axis and a single melamine ligand along the c‐axis, forming an infinite stair‐chain structure. The photoluminescence emission peaks of CuBr_xI_1‐x(melamine) (0 ≤ x ≤ 1) show a red shift from 455 nm to 520 nm with the substitution of Br for I. This finding explains the structure–property relationship of organic–inorganic copper(I) halide complexes and provides guidelines for developing new organic–inorganic optoelectronic materials.

In this study, a dabigatran etexilate edisylate (DBE) was prepared by the reaction crystallization of dabigatran etexilate (DBG) and edisilic acid. According to single crystal X-ray diffraction (SXRD), it was revealed that two DGB were combined with one edisylate and associated with one water for DBE monohydrate. Additionally, the hot stage microscopy showed that the DBE monohydrate was transformed to DBE amorphous solid and then finally shifted to the DBE anhydrate in solid-state. Using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and a hygroscopic test, it was confirmed that the phase transformation of DBE monohydrate to DBE anhydrate was irreversible. Additionally, any other crystal form of DBE anhydrate was not available because it was the most stable phase.

Asymmetric construction of C(sp³)–C(sp³) bond with good stereocontrol of the two connecting carbon centres retaining all carbon or hydrogen substituents is a challenging target in transition metal catalysis. Transition metal-catalysed reductive coupling of unsaturated π-substrates is considered as a potent tool to expediently develop the molecular complexity with high atom efficiency. However, such an asymmetric and intermolecular process has yet to be developed fully. Herein, we report an efficient strategy to reductively couple two prochiral conjugate alkenes using a copper-catalysed tandem protocol in the presence of diboron. Notably, this transformation incorporates a wide range of terminal and internal enynes as coupling partners and facilitates highly diastereo- and enantioselective synthesis of organoboron derivatives with multiple adjacent stereocentres in a single operation.

Iridium(NHC)-catalyzed transfer hydrogenation (TH) of CO₂ and inorganic carbonates with glycerol were conducted, demonstrating excellent turnover numbers (TONs) and turnover frequencies (TOFs) for the formation of formate and lactate. Regardless of carbon sources, excellent TOFs of formate were observed (CO₂: 10,000 h⁻¹ and K₂CO₃: 10,150 h⁻¹). Iridium catalysts modified with the triscarbene ligand showed excellent catalytic activity at 200 °C and are a suitable choice for this transformation which requires a high temperature for high TONs of formate. On the basis of the control experiments, the transfer hydrogenation mechanism of CO₂ was proposed.

The new pentanary thiophosphate, K₂PdPS₄I was prepared with the use of the reactive halide flux and the crystal structure of the compound was determined by single‐crystal X‐ray diffraction method. The structure of K₂PdPS₄I is comprised of anionic infinite one‐dimensional [PdPS₄⁻] chains separated from one another by the K⁺ ions. In addition, The K⁺ ions surround the I⁻ ions through ionic interactions, but there is no direct contact between I⁻ and S²⁻ ions. Although the title compound, K₂PdPS₄I can be regarded as a combination of KPdPS₄ and KI, the one‐dimensional [PdPS₄⁻] chain found in the title compound is different from that of the previously reported KPdPS₄. The bond valence calculations and the structural features indicate that the charge balance of the title compound should be described as [K⁺]₂[Pd²⁺][P⁵⁺][S²⁻]₄[I⁻].