Browsing by Author "Zhang, Sai"
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Item Asymmetric [4 + 2] cycloaddition synthesis of 4H-chromene derivatives facilitated by group-assisted-purification (GAP) chemistry(2021) Rouh, Hossein; Tang, Yao; Zhang, Sai; Ali, Ahmed I. M.; Surowiec, Kazimierz; Unruh, Daniel; Li, GuigenIn this work, we present a strategy for the preparation of functionalized 4H-chromene derivatives via a Cs2CO3-catalyzed [4 + 2] cycloaddition of enantiopure chiral salicyl N-phosphonyl imines with allenoates. Fifteen examples were achieved in excellent yields and diastereoselectivity. The products were purified simply by washing the crude mixture with hexanes following the Group-Assisted Purification (GAP) chemistry/technology to bypass traditional separation methods. The absolute configuration was unambiguously determined by X-ray structure analysis.Item Design and Synthesis of Organic Building Blocks, Monomers and Polymers(2023-12) Zhang, Sai; Li, Guigen; Shi, Huazhong; Liang, RuibingChirality is not only fundamental to research in science, but also intrinsically associated with people's everyday lives. Chirality can be found in every scientific discipline, from astrophysics and geophysics to chemistry and biology, from history and linguistics to computer and information sciences. Therefore, both the research of chirality's genesis and the creation of new chiral applications have switched their focus to the production of advanced chiral building blocks. The current work, which has been addressing several topics including design background, substrate scope increasing, synthetic process, and molecular application, focuses on the idea of multi-layer 3D chirality. Through dual-coupling processes, single C-C bond anchored multi-layer 3D polymer has been created and described. The three layers that make up this new chirality are arranged almost parallel to one another and prevent rotational isomerization. The advancement of optical rotation, UV-visible, and AIE investigation of multilayer 3D polymer provided a great surprise. This research is anticipated to have a significant influence on chiral materials and asymmetric chemistry in the future. KeywordsItem Multilayer 3D Chiral Folding Polymers and Their Asymmetric Catalytic Assembly(2022) Tang, Yao; Jin, Shengzhou; Zhang, Sai; Wu, Guan-Zhao; Wang, Jia-Yin; Xu, Ting; Wang, Yu; Unruh, Daniel; Surowiec, Kazimierz; Ma, Yanzhang; Wang, Shiren; Katz, Courtney; Liang, Hongjun; Li, Yunze; Cong, Weilong; Li, GuigenA novel class of polymers and oligomers of chiral folding chirality has been designed and synthesized, showing structurally compacted triple-column/multiple-layer frameworks. Both uniformed and differentiated aromatic chromophoric units were successfully constructed between naphthyl piers of this framework. Screening monomers, catalysts, and catalytic systems led to the success of asymmetric catalytic Suzuki-Miyaura polycouplings. Enantio- and diastereochemistry were unambiguously determined by X-ray structural analysis and concurrently by comparison with a similar asymmetric induction by the same catalyst in the asymmetric synthesis of a chiral three-layered product. The resulting chiral polymers exhibit intense fluorescence activity in a solid form and solution under specific wavelength irradiation.Item New multiple-layered 3D polymers showing aggregation-induced emission and polarization(2024) Zhang, Sai; Yuan, Qingkai (TTU); Li, Guigen (TTU)An exceptional achiral and chiral multilayer 3D polymer has been created and controlled by uniform and distinct aromatic chromophore units that are multiply sandwiched by naphthyl berths. In order to put together this assembly, it was necessary to search for new catalytic Suzuki-Miyaura polycouplings among various catalytic systems, monomers, and catalysts. Gel Permeation Chromatography (GPC) was able to verify the presence of many framework layers. The resulting achiral and chiral polymers displayed notable optical characteristic.Item Triple-Columned and Multiple-Layered 3D Polymers: Design, Synthesis, Aggregation-Induced Emission (AIE), and Computational Study(2021) Wu, Guanzhao; Liu, Yangxue; Yang, Zhen; Ma, Liulei; Tang, Yao; Zhao, Xianliang; Rouh, Hossein; Zheng, Qixuan; Zhou, Peng; Wang, Jia-Yin; Siddique, Farhan; Zhang, Sai; Jin, Shengzhou; Unruh, Daniel; Aquino, Adelia J. A.; Lischka, Hans; Hutchins, Kristin M.; Li, GuigenConjugated polymers and oligomers have great potentials in various fields, especially in materials and biological sciences because of their intriguing electronic and optoelectronic properties. In recent years, the through-space conjugation system has emerged as a new assembled pattern of multidimensional polymers. Here, a novel series of structurally condensed multicolumn/multilayer 3D polymers and oligomers have been designed and synthesized through one-pot Suzuki polycondensation (SPC). The intramolecularly stacked arrangement of polymers can be supported by either X-ray structural analysis or computational analysis. In all cases, polymers were obtained with modest to good yields, as determined by GPC and 1H-NMR. MALDI-TOF analysis has proven the speculation of the step-growth process of this polymerization. The computational study of ab initio and DFT calculations based on trimer and pentamer models gives details of the structures and the electronic transition. Experimental results of optical and AIE research confirmed by calculation indicates that the present work would facilitate the research and applications in materials.