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Facile and efficient photocatalysts using sunlight, as well as fast and sensitive surface-enhanced Raman spectroscopy (SERS) substrates, are urgently needed for practical degradation of tetracycline (TC). To meet these requirements, a new paradigm for PI/TiO2/Ag organic‒inorganic ternary flexible microfibers based on semiconducting titanium dioxide (TiO2), the noble metal silver (Ag) and the conjugated polymer polyimide (PI) was developed by engineering a simple method. Under sunlight, the photocatalytic characteristics of the PI/TiO2/Ag flexible microfibers containing varying amounts of Ag quantum dots (QDs) were evaluated with photocatalytic degradation of TC in aqueous solution. The results demonstrated that the amount of Ag affected the photocatalytic activity. Among the tested samples, PI/TiO2/Ag-0.07 (93.1%) exhibited a higher photocatalytic degradation rate than PI/TiO2 (25.7%), PI/TiO2/Ag-0.05 (77.7%), and PI/TiO2/Ag-0.09 (63.3%). This observation and evaluation conducted in the present work strongly indicated a charge transfer mechanism. Moreover, the PI/TiO2/Ag-0.07 flexible microfibers exhibited highly sensitive SERS detection, as demonstrated by the observation of the Raman peaks for TC even at an extremely low concentration of 10–10 moles per liter. The excellent photocatalytic performance and SERS detection capability of the PI/TiO2/Ag flexible microfibers arose from the Schottky barrier formed between Ag and TiO2 and also from the outstanding plasmonic resonance and visible light absorptivity of Ag, along with immobilization by the PI. The successful synthesis of PI/TiO2/Ag flexible microfibers holds significant promise for sensitive detection and efficient photocatalytic degradation of antibiotics. [ABSTRACT FROM AUTHOR]

Four ReI complexes with aggregation-induced phosphorescent emission (AIPE) were synthesized with the formula Re(CO)3(Bath- n)Br ( n = 1- 4), where Bath- 1 = 4,7-diphenyl-2-[4-(trimethylsilyl)-phenyl]-1,10-phenanthroline ( 1), Bath- 2 = 4,7-diphenyl-2-[4-(dimethylphenylsilyl)phenyl]-1,10-phenanthroline ( 2), Bath- 3 = 4,7-diphenyl-2-[4-(methyldiphenylsilyl)phenyl]-1,10-phenanthroline ( 3), and Bath- 4 = 4,7-diphenyl-2-[4-(triphenylsilyl)phenyl]-1,10-phenanthroline ( 4), and fully characterized. The single crystals of 1 and 3 were obtained in the monoclinic crystal system by diffusion of diethyl ether into their dichloromethane solutions. Complexes 1- 4 in pure THF ( c ≈ 10-5 mol L-1) mainly present π* → π emission at 370 nm and intraligand charge-transfer (ILCT) emission at 440 nm, whereas the powder samples of 1- 4 solely give lower energy 3MLCT (metal-to-ligand charge transfer) emission at approximately 560 nm. The lifetimes of the powder samples of 1- 4 were measured at room temperature to be 0.335 µs, 0.149 µs, 0.289 µs, and 1.301 µs, respectively. Additionally, the emission spectra and the UV/Vis absorption spectra of 1- 4 were analyzed in different THF/H2O mixtures to investigate their AIPE character. Furthermore, the ground states and the UV/Vis absorption spectra of 1- 4 were also theoretically simulated at the B3LYP/(LANL2DZ+6-31G) level. [ABSTRACT FROM AUTHOR]

The diimine compound 1-[(2′,3′,4′,5′-tetraphenylbiphenyl-4-yl)methyl]-2-(pyridin-2-yl)-1 H-benzo[ d]imidazole (Ph6PyMz) has been designed and synthesized in order to prepare [Cu(Ph6PyMz)(DPEphos)]BF4 {DPEphos = bis[2-(diphenylphosphanyl)phenyl] ether} and [RePh6PyMz(CO)3Br]. The molecular structures of [Cu(Ph6PyMz)(DPEphos)]BF4 and [RePh6PyMz(CO)3Br] were determined by single-crystal X-ray diffraction and IR spectroscopy, and their properties were systematically studied by thermal-stability analyses, photophysical analyses, and electrochemistry. It was found that [Cu(Ph6PyMz)(DPEphos)]BF4 and [RePh6PyMz(CO)3Br] mainly give triplet-ligand-to-ligand charge-transfer transition emission in CH2Cl2 solution and pure triplet-metal-to-ligand charge-transfer transition emission in the solid state. The different photophysical behaviors of [Cu(Ph6PyMz)(DPEphos)]BF4 and [RePh6PyMz(CO)3Br] in different states has been attributed to solvent effects and their higher freedom in CH2Cl2 solution. The energy levels of the highest-occupied and lowest-unoccupied molecular orbitals were measured to be -5.76 and -3.11 eV for [Cu(Ph6PyMz)(DPEphos)]BF4 and -5.69 and -3.42 eV for [RePh6PyMz(CO)3Br], respectively. Finally, the ground-state geometrical structures and the UV/Vis absorption spectra in CH2Cl2 solution were theoretically simulated for [Cu(Ph6PyMz)(DPEphos)]BF4 and [RePh6PyMz(CO)3Br]. [ABSTRACT FROM AUTHOR]

Herein, a series of polyimide (PI)/titanium dioxide (TiO 2 ) organic-inorganic flexible composite microfibers with high photocatalytic performance and good reusability were prepared by combining electrospinning technology and a hydrothermal method. Under simulated sunlight, the photocatalytic characteristics of the as-prepared PI nanofibers, TiO 2 nanorods, and PI/TiO 2 microfibers were evaluated with photocatalytic degradation of Rhodamine B (RhB) solution. Among the tested samples, PI/TiO 2 -3 mL hydrochloric acid-160 °C-14 h (PI/TiO-3-160-14) (100%) exhibited a superior photocatalytic degradation rate compared to pure PI (84.0%) and TiO 2 (62.2%). The enhancement of the photocatalytic performance was attributed to the Z-scheme heterojunction mechanism. When the interface was irradiated by simulated sunlight, the band edge bending, built-in electric field, and Coulomb interaction synergistically facilitated the separation and transport of electron-hole pairs in the heterojunction. This enhanced the oxidation and reduction abilities of the valence and conduction bands of PI/TiO 2 . These results were adequately verified by X-ray photoelectron spectroscopy (XPS) analyses and radical trapping experiments. Additionally, PI/TiO 2 microfibers also demonstrated excellent photocatalytic activity toward methylene blue (MB, 81.4%), methyl orange (MO, 95.9%), and malachite green (KG, 98.9%), underscoring the versatile applicability of PI/TiO 2 . Further supplementary investigations illustrated that PI/TiO 2 microfibers also possess excellent photostability during our extensive recycling photocatalytic experiments.