Browsing by Author "Unruh, Daniel"
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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 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 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.