Advanced Materials Research Vol. 1078

Abstract: A new unsymmetrical photochromic diarylethene 1-(2,5-dimethyl-3-thiazolyl)-2-[2-methyl-5-phenyl-(4-vinyl)-3-thiophene] perfluorocyclopentene (1o) was designed and constructed successfully. And its photochromic reactivity, HPLC, kinetics were also investigated systematically. Upon alternating irradiation with UV and visible light in solution, this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions. Diarylethene 1 changed the color from colorless to orange, in which absorption maxima were observed at 596 nm in acetonitrile. What is more, the photoconversion ratio of 1 is 37%.

Abstract: A new unsymmetrical photochromic diarylethene 1-[(2-methyl-3-benzothiophene)]-2-[2-methyl-5-(1,3-dioxolane)-3-thienyl] perfluorocyclopentene (1o) has been synthesized. In the meantime, its photochromic, kinetics and fluorescence properties were investigated in detail. The results showed this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light in solution [1]. The two isomers differ from each other not only in their absorption spectras, but also in many changes of various physical and chemical properties, such as dielectric constant, refractive index, as well as oxidation/reduction potential, etc [2]. Diarylethene 1 changed the color from colorless to pink upon irradiation with 297 nm UV light, in which absorption maxima were observed at 516 nm in acetonitrile.

Abstract: An asymmetrical photochromic diarylethene1-(2-Methyl-3-benzothiophene)-2-[2-methyl-5-(3-fluoro-4-chloro) phenyl-3-thienyl] perfluorocyclopentene (1o) was synthesized and its phtochromic, fluorescent properties were investigated in detail. This compound exhibited remarkable photochromism, upon irradiation with 297 nm UV light, the colorless solution of 1o turned to violetred with a new visible absorption band centered at 538 nm (ε = 1.17 × 10⁴ L mol^-1 cm^-1) attributable to the closed-ring isomer 1c. The kinetic experiments showed that the cyclization and cycloreversion processes were zeroth and first order reaction, respectively. Moreover, diarylethene 1o also exhibited obviously fluorescence switches along with the photochromism.The emission intensity of diarylethene 1o in a photostationary state was quenched to ca. 27% in hexane.

Abstract: A novel unsymmetrical photochromic diarylethene compound 1-(2-methyl-3-benzothienyl)-2-[3-methyl-2-thienyl] perfluorocyclopentene was designed and constructed successfully. Its optoelectronic properties have been discussed systematically, such as photochromic, fluorescence switch, kinetics experiments in hexane solution and PMMA. The consequences showed that this compound exhibited good reversible photochromism. The maxima absorption of compound closed-ring isomer 1c is 468nm. Upon irradiation with 297nm UV light, Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers upon irradiation with 297 nm UV light.

Abstract: A novel asymmetrical photochromic diarylethene 1-(2-methyl-3-benzothienyl)-2-[2-methyl-5-(3-trifluoromethyl)-3-thienyl] perfluorocyclopentene was synthesized and its photochromic and fluorescent properties were also investigated. The compound exhibited remarkable photochromism, changing from colorless to red after irradiation with UV light and the open-ring isomer of the diarylethene 1 exhibited relatively remarkable fluorescence in hexane solution. The cyclization/cycloreversion process of the compound was determined to be the zeroth/first order reaction.

Abstract: A new fluorescent switch based on a photochromic diarylethene, 1-[2-methyl-5-(4-hydroxymethylphenyl)-3-thienyl]-2-[2-methyl-5-(4-azidomethylphenyl)-3-thienyl] perfluorocyclopentene has been synthesized, And its properties have been discussed systematically in acetonitrile solution and in PMMA, such as photochromic, fluorescence switch and kinetics experiments, and its optoelectronic properties, The results showed that this compound exhibited reversible photochromism and the maxima absorption of compound closed-ring isomer 1c is 590 nm. Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers.

Abstract: The effect of microwave irradiation way on hydrolytic depolymerization of poly (ethylene terephthalate) (PET) was studied at 175°C, 180°C and 185°C. Based on this study, an additional experiment that the intermittent radiation time was one tenth of total reaction time (intermittent radiation (1/10)) was conducted to research the microwave energy utilization. The results showed that the energy efficiency increased as the temperature rose. And the energy utilization of intermittent radiation (1/10) was 16.7% higher than that of the continuous radiation at 175°C.

Abstract: Using anion ligand phenoxyacetic acid (HPOA) and neutral ligand 2,4,6-tri(2-pyridyl)-s-triazine (TPTZ), a series of novel europium complexes EuxYy(TPTZ)2(POA)6·6H2O. The luminescence spectra, luminescence lifetimes and emission quantum efficiencies of the complexes were studied. The results show that doping appropriate amount of Y3+ can significantly increase the luminescence intensities, prolong the luminescent lifetime and improve the emission quantum efficiencies.

Abstract: The development of biological materials provides a new method for the treatment of meniscus injury of the knee joint, and has broad application prospects. Meniscus of knee joint peripheral region blood supply, with self-repair function, non blood supply area is not self-repair function, when the damage appears select biomaterial implanted prosthetic treatment, according to the source is divided into natural scaffolds and artificial synthetic polymer scaffold materials, application compatibility, elastic, according to the toughness, strength and other properties of biological materials and human body, select the appropriate biological materials to replace therapy.

Abstract: The seepage underground is rather complicated in the low permeability reservoir and the heavy oil reservoir. One important point to note is that the seepage in these reservoirs does not follow Darcy's law, which brings difficulty to the development of oil field. Study on low velocity non-Darcy percolation theory, the impact on oil production index is analyzed. The key is the summary of the application in order to provide theoretical references for the rational exploitation of the relevant oil fields.