Intermolecular interactions, photocatalysis and THz-TDS interrelationships for lanthanide phosphine oxide complexes based on {PW12}.

A series of rare earth complexes containing (α-PW12O40)3- and PO ligand are synthesized by water bath in 70 °C, [Ln(OPPh3)4(H2O)3](PW12O40)·4CH3CN (Ln = La, Pr, Nd, Sm, Gd, Tb, Ho 1-7) (OPPh3 = Triphenylphosphine oxide, {PW12} = phosphotungstic acid). The precise structures are confirmed by X-ray single crystal diffraction and the result shows all complexes are isostructural. Complexes 1-7 are fully characterized by PXRD, FT-IR, TGA, UV diffuse reflectance spectra and terahertz time-domain spectroscopy (THz-TDS). Complex 3 exhibits the highest photocatalytic degradation efficiency for methylene blue (MB) in this series of complexes. The experimental results showed that the photodegradation efficiency can remain constant at the level of 95% after five consecutive cycles. The photocatalytic reaction kinetics and mechanism of complexes were investigated. Additionally, complexes also exhibit photocatalytic hydrogen evolution activity. THz-TDS was used to characterize the complexes and its raw materials, the characteristic peaks of OPPh3 (broad peak at 1.20 THz) and phosphotungstic acid (sharp peaks at 0.23, 0.32 THz) were obtained.

Facile high yield, excellent catalytic performance of polyoxometalate-based lanthanide phosphine oxide complexes: Syntheses, structures, photocatalysis and THz spectra.

Water pollution, which continuously threatens human health and the sustainable development of society, has become a major concern. Photocatalytic degradation is an effective strategy to remove organic dyes from wastewater. For this strategy, it is crucial to select the appropriate catalyst. Using triphenylphosphine oxide (OPPh3) as the ligand, phosphomolybdic acid as the anion template, three new lanthanide complexes [Ln(OPPh3)4(H2O)3](PMo12O40)∙4C2H5OH (1-3) (Ln = Sm, Gd, Tb) were synthesized. The raw materials for the reaction are cheap and readily available. The convenient synthesis method is environmentally friendly, with high yield (70%-80%). Complexes 1-3 are all seven-coordinated mononuclear structures centered on lanthanide ions, [PMo12O40]3- anions and solvent molecules are not coordinated with metal ions. These mononuclear structures eventually form complicated 3D supramolecular structures through hydrogen bonds, Mo-O … π or C-H … π weak interactions. Complexes 1-3 photocatalytic degradation of MB have high removal rates, as catalysts have enough stability to be reused, and can be used as excellent catalysts for the degradation of dye molecules in sewage. Among them, the removal rate of MB by photodegradation of complex 2 was highest (99.50%). In addition, the effects of different initial concentrations of MB solution and different types of organic dyes on the photocatalysis experiment were investigated. The photocatalytic reaction mechanism of complexes 1-3 was also studied. Due to the similar structures of complexes 1-3, they have almost the same THz absorption spectra with different absorption intensity, which may be attributed to the difference of the number of weak interactions. Therefore, terahertz spectroscopy can be used as a sensitive method to distinguish and determine small differences between lanthanide-organic complexes. This is the first time that this spectrum has been used to characterize lanthanide phosphine oxide complexes modified by [PMo12O40]3-.

Photo-induced variation of magnetism in coordination polymers with ligand-based electron transfer.

Photo-induced variation of magnetism from ligand-based electron transfer has been extensively studied because of its potential applications in magneto-optical memory devices, light-responsive switches, and high-density information storage materials. In this review, we discussed the progress in the photo-induced variation of magnetism in coordination polymers with ligand-to-metal charge transfer (LMCT), ligand-to-ligand charge transfer (LLCT) and internal ligand charge transfer (ILCT), which provides fundamentals for the rational design of multi-functional materials. We also discussed the design and synthetic strategy of such molecule-based materials and gave views on the current challenges and growth trends in this field.

[Seed rain, soil seed bank and seedling regeneration of Quercus aliena var. acureserrata in different slope directions on the middle Qinling Mountains, China]. / ç§¦å²­ä¸­æ®µä¸åŒå¡å‘é”é½¿æ Žç§å­é›¨ã€åœŸå£¤ç§å­åº“ä¸Žå¹¼è‹—æ›´æ–°.

We studied the seed rain, seed pool quantity and quality dynamics, and seedling develop-ment of natural Quercus aliena var. acureserrata forests in different slopes (sunny, semi-sunny, semi-shady and shady slope) of the middle Qinling Mountains, China. The results showed that seed rain of Q. aliena var. acureserrata generally began at mid-August, peaked from mid-late September to early October, and ended in mid-early November. The dissemination process, occurrence time, and composition of seed rain in four slopes were different. The seed rain intensity of the semi-sunny slope was the highest, which was 134.13 seeds·m-2, followed by sunny slope, semi-shady slope, and shady slope. The seed rain on the sunny slope occurred first, and the duration of the whole and peak period were the longest. The seed rain on the shady slope occurred at the latest, and the duration of the whole and peak period were the shortest. The seed viability and mature seeds proportion were semi-sunny slope > sunny slope > semi-shady slope > shady slope. From the end of the seed rain to the August of the next year, the size of soil seed bank was semi-sunny slope > sunny slope > semi-shady slope > shady slope. The number of mature, immature and nibbled seeds and seed vigor of soil seed bank showed a decreasing trend with time, while the number of moldy seeds increased. The seeds in soil seed bank mainly existed in the litter layer, followed by the 0-2 cm soil layer, with few seeds in the 2-5 cm soil layer. The seedling density of Q. aliena var. acureserrata was significantly different among the four slopes. The semi-sunny slope, with the highest seedling density, was more suitable for seed germination and seedling growth of Q. aliena var. acureserrata than other slopes.

Copper-Mediated Aminoazidation, Aminohalogenation, and Aminothiocyanation of ß,γ-Unsaturated Hydrazones: Synthesis of Versatile Functionalized Pyrazolines.

A versatile method for the rapid synthesis of diverse functionalized pyrazolines has been developed based on copper-mediated aminofunctionalization of ß,γ-unsaturated hydrazones. The scope of this strategy encompasses a range of difunctionalization reactions: aminoazidation, aminohalogenation, and aminothiocyanation. These reactions provide straightforward access to a series of useful pyrazoline building blocks containing various functional groups that are hard to access traditionally.