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991.
Mr. Chen Qian, Dr. Zhimin Ma, Mr. Jianwei Liu, Mrs. Xue Zhang, Prof. Shitao Wang and Prof. Zhiyong Ma. In this article, we report a newly designed molecule composed of a dihydroazulene (DHA) group and a phenothiazine (PTZ) moiety, which achieves aggregation-induced emission enhancement (AIEE), mechanochromism and “gated” solid-state photochromism upon stimulation by an external force. Grinding loosens intermolecular interactions in the crystal and causes a red-shift of fluorescence from 570 nm to 600 nm. Meanwhile, the ring-opening reaction of DHA unit is activated by grinding and a remarkable photochromism could be observed from the grinded powder. The reddish emission of the grinded powder peaked at 600 nm weakened gradually and finally became dark, and a new absorption band at 470 nm emerged in the absorption spectra. Time-dependent density functional theory (TD-DFT) calculation results reveal that the intramolecular intramolecular charge-transfer (ICT) process is replaced by a locally excited (LE) emission on the DHA group, which leads to the quenching of fluorescence. Its impressive photochromic property inspired us to a simple but effective way to develop an encryption system which can let the correct information be displayed upon external stimulation. 相似文献
992.
Dongyao Li Chunmiao Ma Prof. Junfeng Xiang Kai Zhang Ling Yang Prof. Quan Gan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(45):11663-11669
A strategy to reversibly switch the parallel/antiparallel helical conformation of aromatic double helices through the formation/breakage of a disulfide bond is presented. Single-crystal X-ray structures, NMR, and circular dichroism spectroscopy demonstrate that the double helices with terminal thiol groups favor an antiparallel helical arrangement both in the solid state and in solution, while the P/M bias of helicity induced by chiral segments from another extremity of the sequence is weak in this structural motif. The antiparallel helices can be rearranged to parallel helices through the disulfide connection of the sequences. This change enhances the bias of helical handedness and results in absolute chirality control of the double helices. The handedness-mediated process can be governed by the oxidation-reduction cycle, thereby switching the structural arrangement and the enhancement of chiral bias. In addition, we find that the sequences can dimerize into an intermolecular double helix with the disulfide connection. And the helical handedness is also fully controlled due to the head-to-head structural motif. 相似文献
993.
Zi-Qi Zhou Qi-Rui Shui Prof. Rui-Biao Fu Yuan-Bin Fang Prof. Zu-Ju Ma Prof. Xin-Tao Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(51):12976-12980
The discovery of new nonlinear optical (NLO) crystals with excellent properties is in urgently demand because of their ability to generate coherent light. Herein, we report an unique NLO lead bromide formate, KCs2[Pb2Br5 (HCOO)2], which has been synthesized by a mix-solvothermal method. KCs2[Pb2Br5(HCOO)2] exhibits strong phase-matching second-harmonic generation (SHG) response (6.5×KDP), large birefringence (0.16@ 1064 nm), and a wide transparent window in most visible light and mid-IR region. Interestingly, KCs2[Pb2Br5(HCOO)2] features a polar 3D lead-bromide framework in which adjacent Pb−Br layers containing coplanar Pb6Br6 rings are not only parallel to each other, but also orient in the same direction. These oriented arrangements are responsible for the strong SHG response and large birefringence that are elucidated by both local dipole moment and theoretical calculations. This research provides a new strategy to explore subsequent NLO crystals. 相似文献
994.
Gen Liu Xue Yu Rui Xu Xiaodong Zhu Yanqing Ma Prof. Lei Ma 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(70):17620-17627
Chemical bath deposition method has been used to synthesize a variety of ZnO morphology structures. However, the specificity and interaction of acetate and ammonium ions with ZnO crystal during the growth process remain elusive. This study contributes to understand the roles of ammonium acetate on the growth mechanism of ZnO in Zn(NO3)2-HMTA system. The growth process indicates that the nucleation experienced Zn2+-layered basic zinc salts (LBZs)-ZnO process, while the self-assembled unit changed from urchin-shaped, rod-shaped to a fully coupled twin-shaped structure with increasing ammonium acetate concentration. Ammonium acetate dominates the growth process by combing the ligand-ligand interaction of acetate ions binding to the same Zn-rich (0001) polar surface and ammonium ions regulating hexamethylenetetramine (HMTA) hydrolysis. Relatively regular hexagonal wurtzite structure and a dissolve-renucleation-regrowth process which retains the twin-shaped template and renucleates at the same position are observed at ∼10 mM ammonium acetate. Photoelectrochemistry (PEC) measurements show that the uniform hexagonal ZnO rods (Y-10, the sample named as Y-x (x represents x mM ammonium acetate, herein, x is 10 mM)) have a maximum photocurrent density of 1.54 mA cm−2 at 1.23 V (vs. RHE), much higher than that of the dumbbell-shaped ZnO rods (Y-50, 0.20 mA cm−2) at the same voltage. These results provide a further explanation of morphology regulation mechanisms on ZnO synthesis processes and pave the road for more practical applications. 相似文献
995.
Ben Abdelouahab N. Gossard A. Ma X. Dialla H. Maillet B. Rodts S. Coussot P. 《Cellulose (London, England)》2021,28(9):5321-5334
Cellulose - This study concerns the spatial evolution of the internal components of a macroscopic sample of cellulose slurry during its convective drying. In a first stage, some water is extracted... 相似文献
996.
997.
998.
Shiyi Yu Liao Kai Liu Shuangshuang Ma Ying Chi Yaping Guo Danyang Hu Ruoxi Liu Pengfei Zhu Yun 《Moscow University Chemistry Bulletin》2021,76(5):343-351
Moscow University Chemistry Bulletin - The genus Achillea L. (Family: Asteraceae) is a kind of perennial plant, mostly distributed in north western region of China, especially in Tianshan Mountains... 相似文献
999.
Liu Changqi Huo Dongying Yang Xu Ma Zhanwen Zhou Jianjin Han Chao Bai Xiaohou Wu Kang Zhang Yu Wang Junrun Yao Zeen Wei Zheng 《Journal of Radioanalytical and Nuclear Chemistry》2021,330(3):1091-1099
Journal of Radioanalytical and Nuclear Chemistry - A Frisch-grid Ionization Chamber (FGIC) for the measurement of low activity of alpha-particle emitters has been built. The design and performance... 相似文献