Borate Fluoride and Fluoroborate in Alkali-Metal Borate Prepared by an Open High-Temperature Solution Method

By incorporation of the largest-electronegativity F atoms into borate, two novel halogen-containing borates, Li₆RbB₂O₆F and K₃B₃O₃F₆, have been synthesized. Interestingly, Li₆RbB₂O₆F is the first borate fluoride in alkali-metal borate. Meanwhile, K₃B₃O₃F₆ appears to be the first confirmed alkali-metal fluoroborate crystal grown by a high-temperature solution in air

Borate Fluoride and Fluoroborate in Alkali-Metal Borate Prepared by an Open High-Temperature Solution Method

By incorporation of the largest-electronegativity F atoms into borate, two novel halogen-containing borates, Li₆RbB₂O₆F and K₃B₃O₃F₆, have been synthesized. Interestingly, Li₆RbB₂O₆F is the first borate fluoride in alkali-metal borate. Meanwhile, K₃B₃O₃F₆ appears to be the first confirmed alkali-metal fluoroborate crystal grown by a high-temperature solution in air

Borate Fluoride and Fluoroborate in Alkali-Metal Borate Prepared by an Open High-Temperature Solution Method

By incorporation of the largest-electronegativity F atoms into borate, two novel halogen-containing borates, Li₆RbB₂O₆F and K₃B₃O₃F₆, have been synthesized. Interestingly, Li₆RbB₂O₆F is the first borate fluoride in alkali-metal borate. Meanwhile, K₃B₃O₃F₆ appears to be the first confirmed alkali-metal fluoroborate crystal grown by a high-temperature solution in air

Computer-Assisted Design of a Superior Be₂BO₃F Deep-Ultraviolet Nonlinear-Optical Material

Deep-ultraviolet (DUV) nonlinear-optical (NLO) materials generating coherent DUV light by a direct second-harmonic-generation (SHG) process have long been pursued as industrially useful lasers. For several decades, KBe₂BO₃F₂ (KBBF) has been regarded as the best DUV-NLO material; it is characterized by a short DUV phase-matching edge of 161 nm and a large SHG coefficient of 0.47 pm/V. However, it suffers a strong layering tendency, hindering the growth of large crystals for commercial use. Here, we use a computer-aided swarm structure searching technique to design an alternative DUV-NLO material with a new atmospheric-pressure phase Be₂BO₃F₂ with a <i>P</i>6̅2<i>c</i> space group (γ-BBF) that outperforms the DUV-NLO properties of KBBF. The predicted DUV phase-matching edge and SHG coefficient of γ-BBF are 152 nm and 0.70 pm/V, respectively. The structure of γ-BBF reduces the layering tendency compared with KBBF because of the absence of K atoms in the γ-BBF crystal. Our work paves the way for superior DUV-NLO materials that can be grown as large crystals for commercial applications

Prediction and Characterization of NaGaS₂, A High Thermal Conductivity Mid-Infrared Nonlinear Optical Material for High-Power Laser Frequency Conversion

Infrared nonlinear optical (IR NLO) crystals are the major materials to widen the output range of solid-state lasers to mid- or far-infrared regions. The IR NLO crystals used in the middle IR region are still inadequate for high-power laser applications because of deleterious thermal effects (lensing and expansion), low laser-induced damage threshold, and two-photon absorption. Herein, the unbiased global minimum search method was used for the first time to search for IR NLO optical materials and ultimately found a new IR NLO material NaGaS₂. It meets the stringent demands for IR NLO materials pumped by high-power laser with the highest thermal conductivity among common IR NLO materials able to avoid two-photon absorption, a classic nonlinear coefficient, and wide infrared transparency

Novel Ultrasound-Promoted Parallel Synthesis of Trifluoroatrolactamide Library via a One-Pot Passerini/Hydrolysis Reaction Sequence and Their Fungicidal Activities

An ultrasound-promoted one-pot Passerini/hydrolysis reaction sequence has been developed for the synthesis of trifluoroatrolactamide derivatives using a diverse range of trifluoroacetophenones and isonitriles in acetic acid. Parallel synthesis in a centrifuge tube using a noncontact ultrasonic cell crusher was used in this study as an efficient method for the rapid generation of combinatorial trifluoroatrolactamide libraries, and subsequent biochemical evaluation of the resulting compounds indicated that they possessed excellent broad-spectrum fungicidal activities. <i>N</i>-(4-chlorophenyl)-2-(4-ethylphenyl)-3,3,3-trifluoro-2-hydroxypropanamide and <i>N</i>-(4-chlorophenyl)-3,3,3-trifluoro-2-hydroxy-2-(4-methoxyphenyl)­propanamide, in particular, showed significant fungicidal activities against all of the fungal species tested in the current study

First Principle Assisted Prediction of the Birefringence Values of Functional Inorganic Borate Materials

Prediction of the birefringence values of borate is very essential for developing new optical materials in UV range. In this paper, the birefringence values of five lead borates, Pb₈B₉O₂₁F, PbBiBO₄, Pb₃BO₄F, Pb₆B₃O₁₀Cl, and Pb₂BO₃F with network B–O structure or isolated BO₃ groups, are calculated by the first principle method. The calculations show that PbBiBO₄, Pb₃BO₄F, and Pb₂BO₃F have the large birefringence, greater than 0.1. Pb₂BO₃F, especially, is the first compound with large birefringence above 0.08 among positive uniaxial borate crystals. It is found that the parallel arrangement of fundamental building units is not the only light anisotropy active character. In the further research of Pb₂BO₃F, polarization disproportionation via a visualized model is first put forward for identifying the origin of large birefringence, which will be helpful to search for new optical materials with suitable birefringence

Discovery of Novel Benzoxaborole-Containing Streptochlorin Derivatives as Potential Antifungal Agents

Streptochlorin is a kind of indole alkaloid derived from marine microorganisms. It is a promising lead compound due to its potent bioactivity in preventing many phytopathogens, as shown in our previous study. To explore the potential applications of this natural product, a series of novel benzoxaborole-containing streptochlorin derivatives were designed and synthesized through a one-step and catalyst-free reaction in water at room temperature. All target compounds were first screened for their antifungal profiles in vitro against six common phytopathogenic fungi. The results of bioassay revealed that most of the designed compounds exhibited more significant antifungal activities against Botrytis cinrea, Gibberella zeae, Rhizoctorzia solani, Colletotrichum lagenarium, and alternaria leaf spot under the concentration of 50 μg/mL, and this is highlighted by compounds 4i and 5f, which demonstrated impressive antifungal effects against G. zeae and R. solani, with their corresponding EC50 values 0.2983 and 0.2657 μg/mL, which are obviously better than positive control flutriafol and boscalid (5.2606 and 1.2048 μg/mL, respectively). Scanning electron microscopy on the hyphae morphology showed that compound 5b might cause mycelial abnormalities of G. zeae. 3D-QSAR studies of CoMFA and CoMSIA were carried out on 29 target compounds with antifungal activity against B. cinrea. The analysis results indicated that introducing appropriate electronegative groups at the 5-position of benzoxaborole and the 4,5-positions of the indole ring could effectively improve the anti-B. cinrea activity. Moreover, compound 5b showed good antifungal activities in vivo against Phytophthora capsici. Molecular docking was further explored to ascertain the practical value of the active compound as a potential inhibitor of LeuRS. The abovementioned results indicate that the designed benzoxaborole-containing streptochlorin derivatives could be further studied as template molecules of novel antifungal agents

Na₃Ba₂(B₃O₆)₂F: Next Generation of Deep-Ultraviolet Birefringent Materials

Birefringent materials are of great importance in optical communication and the laser industry, as they can modulate the polarization of light. Limited by their transparency range, few birefringent materials, except α-BaB₂O₄ (α-BBO), can be practically used in the deep ultraviolet (UV) region. However, α-BBO suffers from a phase transition and does not have enough transparency in the deep UV region. By introducing the relatively small alkali metal Na⁺ cation and the F^– anion to keep the favorable structural features of α-BBO, we report a new birefringent crystal Na₃Ba₂(B₃O₆)₂F (NBBF), which has the desirable optical properties. NBBF not only maintains the large birefringence (Δ<i>n</i> = <i>n</i>_o – <i>n</i>_e = 0.2554–0.0750 from 175 nm to 3.35 μm) and extends its UV cutoff edge to 175 nm (14 nm shorter than α-BBO) but also eliminates the phase transition and has the lowest growth temperature (820 °C) among birefringent materials. These results demonstrate that NBBF is an attractive candidate for the next generation of deep UV birefringent materials