Browsing by Author "Zheng, Qixuan"
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Item Synthesis of pharmaceutical co-crystals and functionalized polymers for micropollutant remediation(2022-05) Zheng, Qixuan; Hutchins, Kristin M.; Cozzolino, Anthony F.; Krempner, ClemensCrystal engineering, as a rapidly growing and developing research field, aims at design and synthesis of new solids with desired physical and chemical properties via reliable intermolecular interactions such as hydrogen bonds, halogen bonds, π‧‧‧π staking, and coordination bonds. We have applied crystal engineering strategies to the design and synthesis of bipyridine based pharmaceutical co-crystals where we confirm that the supramolecular hydrogen-bond synthon behaviour of the selected NSAIDs is reliable, regardless of minor changes to bipyridine co-formers. A rarity of motif in acid-bipyridine co-crystals was reported, where we observed the expected COOH···N synthon breakdown and formation of a pyridyl dimer. Also, a unique robust supramolecular complex of diclofenac was synthesized and can be used for crystal-to-crystal solvent exchange while maintaining crystallinity. We have also applied principles of crystal engineering to the predictions in co-crystals of acetazolamide (ACZ) and co-crystal formers (CCFs) containing either only aromatic nitrogen acceptor sites or both acceptor and donor moieties. The pKa values, basicity of CCFs, and geometric complementarity all play a crucial role in predicting synthon formation in ACZ co-crystals. We demonstrate a behavior rarely observed in co-crystal ACZ‧BPP, where 1,3-di(4-pyridyl)propane (BPP) as a CCF engages with ACZ at both the sulfonamide and amide donor sites. We utilize co-crystallization strategies to synthesize salts of trimethoprim (TMP) and monopyridines. All salts exhibit higher aqueous solubility than TMP. Specifically, two salts are ten times more soluble than TMP. One salt-hydrate is promising as CCF nicotinic acid (NA) is on the GRAS list and the solid exhibits high aqueous solubility, good thermal stability, and good stability under ambient conditions. This dissertation will also focus on the design and synthesis of polymer materials that can bind and remove micropollutants from water. We synthesized both linear and cross-linked polymers including both hydrophobic and hydrophilic polymers. Concentration of micropollutants such as propranolol-HCl (PPL-HCl) and 2-naphthol (2NO) successfully decrease by varying degrees from water after binding over a time frame of 1-4 h.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.