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101.
Chen Jiu-ju Yang Hai-bin Chang Lian-xia Fu Wu-you Zeng Yi Zhu Hong-yang Zou Guang-tian 《Frontiers of Physics in China》2007,2(1):92-95
The effect of ultrasound irradiation on molybdenum trioxide has been investigated. Under ultrasonic irradiation, spherical-like
MoO3 nanoparticles were obtained, while bulk-like MoO3 nanoparticles were prepared without ultrasonic irradiation. The changes in the physicochemical properties of MoO3 have been investigated using techniques such as X-ray powder diffraction (XRD), field emission scanning electron microscopy
(FE-SEM) and ultraviolet and visible spectroscopy (UV-vis). The physicochemical changes of MoO3 due to ultrasound irradiation have been attributed to the sonochemical cavity collapse onto the molybdenum trioxide particles.
The ultrasonically prepared particles can also greatly improve the photochromism efficiency.
相似文献
102.
可见光驱动光环化的荧光turn-on型二芳基乙烯分子开关是超分辨显微成像的理想材料, 但目前关于该类型分子的报道仍较少. 本工作合成了一种基于苯并[b]萘并[1,2-d]噻吩(BNTP)的405 nm可见光驱动光环化的荧光turn-on型二芳基乙烯分子BNTP-BTTO4, 同时系统研究了该分子的光物理性能与稳定性, 并借助密度泛函理论(DFT)计算厘清了分子实现可见光驱动光环化及荧光turn-on原因. 另外, 本研究发现BNTP引入后分子表现出比参比分子Ph-BTTO4更优异的抗疲劳性、热稳定性和光稳定性, 尤其是在历经200 min 405 nm可见光照射后, BNTP-BTTO4(c)吸收强度只下降4%, 光稳定性大幅提升. 本研究为设计开发性能优异的可见光驱动光环化的荧光turn-on型二芳基乙烯提供了新的思路. 相似文献
103.
Kazuyuki Horie Seiichiro Murase Satoshi Takahashi Madoka Teramoto Hidemitsu Furukawa 《Macromolecular Symposia》2003,195(1):201-208
The molecular design for large photo-induced refractive index changes in transparent visible light region was proposed and realized with norbornadiene polymers and poly(vinyl cinnamate). The patterning of pure refractive-index contract on their transparent films was made with near-field scanning optical microscopy (NSOM). Reversible fluorescence patterning on polymer films is also presented by using controlled energy transfer from a fluorescent pyromethene to a photochromic diarylethene. 相似文献
104.
Lucie Čechová Dr. Juraj Filo Dr. Martin Dračínský Dr. Chavdar Slavov Dazhong Sun Dr. Zlatko Janeba Dr. Tomáš Slanina Prof. Dr. Josef Wachtveitl Dr. Eliška Procházková Dr. Marek Cigáň 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(36):15720-15724
Photochromic systems with an ultrahigh rate of thermal relaxation are highly desirable for the development of new efficient photochromic oscillators. Based on DFT calculations, we designed a series of 5-phenylazopyrimidines with strong push–pull character in silico and observed very low energy barriers for the thermal (Z)-to-(E) isomerization. The structure of the (Z)-isomer of the slowest isomerizing derivative in the series was confirmed by NMR analysis with in situ irradiation at low temperature. The substituents can tune the lifetime of thermal back isomerization from hundreds of microseconds to several nanoseconds (8 orders of magnitude). The photoswitching parameters were extracted from transient absorption techniques and a dominant rotation mechanism of the (Z)-to-(E) thermal fading was proposed based on DFT calculations. 相似文献
105.
106.
Nino Malic Richard A. Evans 《Journal of polymer science. Part A, Polymer chemistry》2012,50(7):1434-1444
We report a conjugation system for the enhancement of photochromic dye performance in rigid matrices using widely available, cheap, chemically robust and compatible polymeric starting materials, namely poly(propylene oxide) (PPO) and poly(1,2‐butylene oxide). Conjugation of these soft (low Tg) polymers to an indeno‐fused naphthopyran photochromic dye, in a telechelic geometry, gives access to a wide range of accelerated and tuned fade speeds (decoloration) via variation in molecular weight. The t1/2 and t3/4 fade speeds for PPO conjugates (polymer molecular weights ranging between ca. 425 and 2000) are accelerated by 35–58 and 51–76%, respectively, compared with the nonconjugated control dye. Longer oligomers provide faster decoloration approaching that obtained in solution. The stability of the polyethers allows functionalization using a wide variety of chemistries, including harsh acid catalyzed transformations, providing an overall facile synthesis of photochromic dye‐polymer conjugates in high yield and purity. In addition, these polymers give easy access to conjugates with star‐type architectures, which provide an even further improvement in performance compared with their linear counterparts with less conjugated polymer needed per dye to achieve a given fade speed. © 2012 Commonwealth of Australia. J Polym Sci Part A: Polym Chem, 2012 相似文献
107.
108.
Dr. Satoshi Muratsugu Masa‐aki Kishida Dr. Ryota Sakamoto Prof. Dr. Hiroshi Nishihara 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(51):17314-17327
The photochemical properties and the mixed‐valence state of bis(ferrocenylethynyl)benzodimethyldihydropyrene ( 1 ) and other benzodimethyldihydropyrene (BzDHP) derivatives were investigated to understand the reversible photoswitching in the electronic communication of 1 . Absorption spectra of 1 were characterized by UV/Vis spectroscopy and calculated by using time‐dependent density functional theory (TD‐DFT), and the d orbitals of the ferrocene (Fc) moieties were shown to contribute to the occupied valence orbitals that were responsible for the photochromic behavior. 1 exhibited reversible photoisomerization in THF; however, photochromic behavior was not observed in dichloromethane. Analysis of redox potentials showed that the mixed‐valence state of 1 was more stable in dichloromethane than in THF. This is consistent with the observation that chemical oxidation led to an intervalence charge‐transfer (IVCT) band between the Fc moieties in the mixed‐valence state of 1 in dichloromethane, whereas such a band was not observed for one‐electron‐oxidized 1 in THF. Bis(pentamethylferrocenylethynyl)benzodimethyldihydropyrene ( 2 ) did not show photochromic behavior even in THF. The mixed‐valence state of 2 was much less stable than that of 1 in dichloromethane, and no obvious IVCT band was observed for one‐electron‐oxidized 2 in dichloromethane. The difference in the redox contribution of Fc and pentamethylferrocene (Me5Fc) to BzDHP played an important role for these redox and photochromic behaviors; this was supported by analysis of valence orbital energies from DFT calculations. Designing molecules that connect redox centers through the use of a photochromic linker with a redox potential close to that of the redox centers could constitute a useful approach for the production of photochromic redox‐active metal complexes with strong electronic communication. 相似文献
109.
V. F. Traven V. S. Miroshnikov T. A. Chibisova V. A. Barachevsky O. V. Venidiktova Yu. P. Strokach 《Russian Chemical Bulletin》2005,54(10):2417-2424
New indoline spiropyrans of the coumarin series were synthesized by the condensation of indoline and hydroxyformylcoumarin
derivatives. Spiropyrans, viz., derivatives of 8-formyl-7-hydroxy-4-methylcoumarin and 5-formyl-6-hydroxy-4-methylcoumarin, under irradiation are transformed
into open forms, which are recyclized in the dark. The compounds formed by the condensation of the indoline derivatives with
3-formyl-4-hydroxycoumarin have an open structure of the merocyanine dyes and are transformed into spiro forms neither in
the dark nor under irradiation with the visible light.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2342–2349, October, 2005. 相似文献
110.
An optical method is presented which permits the determination of the free surface velocity of liquid films flowing on curved surfaces. The feasibility of this technique, which involves the laser tomography and photochromic dye activation techniques, is demonstrated on an oil film flowing around a finned tube. Results for different tube geometries and flow conditions are presented. Advantages and limits of the laser photochromic velocimetry technique are discussed. 相似文献