Journal of The Chinese Chemical Society最新文献

The photophysical features of 3-(benzo[d]oxazol-2-yl)-2-hydroxy-5-methoxy benzaldehyde (BOHMB) were investigated through experimental (J. Phys. Chem. A 2019, 123, 10,246–10,253) and theoretical (Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2022, 266, 120,406) methods. However, the effect of substituent groups on the excited state proton transfer process has not been studied. In this work, the excited state intramolecular proton transfer (ESIPT) dynamics and photophysical properties of BOHMB with different substituent groups were investigated by density-functional theory (DFT) and time-dependent DFT (TDDFT) methods at CAM-B3LYP/6-311G(d,p) level. The primary parameters related to hydrogen bonding and infrared vibration frequency were obtained to understand the ESIPT properties of BOHMB derivatives. The results indicate that the excited-state intramolecular hydrogen bond (ESIHB) strengthening behaviors, and the intramolecular hydrogen bond O1–H2···O3 for 1a in the S₁ state is the strongest among BOHMB derivatives. From the calculated potential energy curves, it can be inferred that the substitution and position of NH₂ and NO₂ groups will regulate the excited-state energy barrier and thus affect the ESIPT process. The molecular absorption peak and fluorescence peak are affected by different substituting groups and different positions.

This study achieves successful synthesis of organ-ometallic Cp* cobalt complexes with 1,4-diisocyanobenzene as a linear bridging ligand, over-coming solubility challenges. Investigating stepwise and self-assembly pathways, it results in characterized rectangular tetranuclear Cp*Co/1,4-diisocyanobenzene complexes using X-ray diffraction and various spectro-scopic techniques. More details about this figure will be discussed by Dr. Sodio C. N. Hsu and his co-workers on page 376–384 in this issue.

BiOBr_xCl_1-x solid solution with oxygen vacancies was synthesized using a simple one-step hydrothermal method. The sample was characterized using comprehensive characterization techniques, and the results showed that the solid solution material was successfully prepared. Adjusting the relative proportion of halogens in BiOBr_xCl_1-x solid solution has a significant impact on the morphology, optical properties, and photocatalytic activity of the sample, and oxygen vacancies are introduced into the material. The presence of oxygen vacancies improves the separation efficiency of charge carriers and facilitates the activation of oxygen molecules into superoxide radicals. Among them, BiOBr_0.2Cl_0.8 showed flower-like microspheres morphology and exhibited the best photocatalytic activity. After 30 min of dark adsorption and 1 h of simulated sunlight exposure, the removal rate of methyl orange (MO) was 92.5%, which was 2.38 times higher than that of pure BiOBr (38.9%) and 2.09 times higher than that of pure BiOCl (44.3%), respectively.

To extract V⁵⁺ ions from the ferruginous siltstone in the Abu Zeneima region of Southwestern Sinai, Egypt, a chelating polyimine ligand (PVAm-Ben) was synthesized via a condensation reaction involving polyvinyl amine and α-hydroxy ketone (Benzoin). The structure of PVAm-Ben underwent comprehensive characterization employing various techniques, namely; FT-IR, ¹H-NMR, ¹³C-NMR, and GC/MS analyses. Experimental factors controlling such as pH, time, initial concentration, dosage, temperature, and stripping, were systematically optimized to enhance measurement accuracy. Under conditions of 25°C, 0.015 mol/L, and 30 minutes, PVAm-Ben/C₂H₄Cl₂ exhibited remarkable retention capacity at pH 3. Linear regression analysis results suggested the release of a mole of H⁺ during the extraction process. The stability constant (log β = 2.1882) of the PVAm-Ben/V⁵⁺ complex was determined, yielding a value of 154.24. The stoichiometry mechanism between PVAm-Ben and V⁵⁺ ions displayed a linear correlation (slope: 0.9922), signifying 1 mole of PVAm-Ben reacting with 1 mole of vanadium. The pseudo-second-order kinetic model indicated an exothermic, spontaneous, and advantageous extraction process at low temperatures. Efficient stripping of PVAm-Ben/C₂H₄Cl₂ loaded with vanadium was achieved using 0.05 M NaOH with a 99% efficiency rate. Ultimately, enhanced variables were employed to yield a V₂O₅ concentrate with a vanadium content of 55% and a purity level of 98.21%.

Two Hyptis plants endemic to Taiwan, H. rhomboides and H. suaveolens, contained xanthine oxidase inhibitors. To chemically investigate more herbs of the same genus, this study aimed to explore bioactive constituents from Hyptis spicigera leaf and the aerial part of H. brevipes, which would also enrich the chemotaxonomic basis for the Hyptis plants. The EtOH extract of the plant materials was fractionated by liquid-liquid partitioning, followed by separation over various chromatography. High-performance liquid chromatography-solid phase extraction-nuclear magnetic resonance hyphenation, a sustainable and environmentally friendly instrument, was applied to accelerate the chemical investigation of each subfraction. Eighteen isolates from Hyptis spicigera leaf and 14 compounds from H. brevipes aerial part were characterized. Of these, 12 compounds are rosmarinic acid derivatives, of which 9′-O-methyl melitrate A (10) and sagecoumarin methyl ester (22) are tentatively identified as new compounds. In total, 25 compounds were separated and characterized from Hyptis spicigera leaf and H. brevipes aerial part. Of these, seven of them (2–4, 11, 12, 18, 20) are in common between these two species, and 17 isolates (2–4, 8-14, 22, 23, and 26-30) are phenylpropanoids which are commonly distributed in the Labiatae family.

Sodium (E)-3-hydroxy-4-((2-hydroxynaphthalen-1-yl)diazenyl)naphthalene-1-sulfonate (Calcon, CAL), is employed for the first time as a reversible colorimetric chemosensor to detect and measure Ce³⁺ and H₂PO₄⁻ sequentially in the aqueous medium. The detection process has two steps. The interaction of CAL and Ce³⁺ in the first step with a noticeable color shift from purple to blue. Further, the reaction between CAL-Ce³⁺ and H₂PO₄⁻ shows a clear color return from blue back to initial purple similar to that for CAL. The UV–visible examination of this color return reveals that H₂PO₄⁻ removes Ce³⁺ and restores CAL content. The results showed that CAL and CAL-Ce³⁺ had a strong binding affinity and adequate detection limits for the Ce³⁺ and H₂PO₄⁻, respectively. For Ce³⁺, the linear range and detection limit are 1.20 × 10⁻⁶-1.02 × 10⁻⁴ and 2.0 × 10⁻⁷molL⁻¹, while for H₂PO₄⁻, they are 2.0 × 10⁻⁷-8.7 × 10⁻⁶ and 3.0 × 10⁻⁸ molL⁻¹. Finally, we measured these two ions in real samples using this methodology. Furthermore, the examination of the suggested receptor's logical behavior revealed that it can operate as a colorimetric chemosensor of the INHIBIT type, receiving chemical inputs and producing a UV–visible absorbance signal as the output. If Ce³⁺ and H₂PO₄⁻ inputs are added in proper order, the receptor may also function as a molecular “keypad lock.”