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- 저자 : Guoquan Yan (검색결과 2 건)
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Qiang Wei,Guoquan Yan,Qianrong Li 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.10
1,4-Dihydropyridines provide the principal structural components for calcium channel blockers, which are usually studied by expeditious qualitative and quantitative analyses in pharmaceutical research and development. In this work, through the use of high-resolution electrospray ionization ion-trap time-of-flight multistage tandem mass spectrometry (ESI-IT-TOF/MSn), the accurate masses and fragmentation pathways of protonated derivatives (1–12) of 1,4-dihydropyridine derivatives are determined and rationalized. All protonated molecules are further fragmented by loss of the neutral groups 4-R1H, 3-C2H4 , 5-C2H4 , R2OH, or CO, yielding three fragmentation pathways with two different fragment nuclei of pyridine or 1,4-dihydropyridine. During the formation process of the pyridine nucleus, one pathway is that product ions at m/z 224 or 252 are the common diagnostic masses in most compounds; the other pathway is that the product ions are obtained by the loss of R2OH. The 1,4-dihydropyridine nucleus in three compounds arises from double C2H4 elimination. Simultaneously, this study supplies abundant special fragment information, which potentially provides a new method for structural studies of 1,4-dihydropyridine derivatives.
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Jeong, Keuk-Min,Park, Sung Soo,Nagappan, Saravanan,Min, Guoquan,Zhang, Yongxu,Qu, Minming,Zhang, Yan,Ha, Chang-Sik Elsevier Sequoia 2019 Progress in organic coatings Vol.134 No.-
<P><B>Abstract</B></P> <P>Highly transparent organic-inorganic hybrid UV-curable coating formulations were obtained using silica particles with different functional groups, such as methyl group, long alkyl chain, benzene ring, isobutyl group, and fluorine group. Their surface chemical structures were analyzed by attenuated total reflection-flourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The surface morphology of the hybrid UV-curable coating formulated materials was observed by atomic force microscopy and high-resolution scanning electron microscopy. The hydrophobic and oleophobic properties were investigated by contact angle measurements using water, hexadecane, and artificial fingerprint solution. The prepared hybrid UV-curable coating materials exhibited excellent transparency, good hydrophobic, and oleophobic properties in addition to the high thermal stability and high pencil hardness up to 8H. In particular, the hybrid UV-curable coating materials with a small amount of fluorine-functionalized silica showed balanced coating performance, such as high pencil hardness (6 H) and good amphiphobic properties (static contact angles in water (135°), oil (100°), and artificial fingerprint solution (114°)), as well as excellent transparency of more than 95% of transmittance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Surface morphology, amphiphobicity, scratch resistance, and transparency were controlled by functionalized silica particles. </LI> <LI> Alkyl chain length on surface of silica particle changed surface roughness, which can impart a physical resistance effect. </LI> <LI> UV curable silica hybrid coating materials exhibited high contact angles in water, oil, artificial fingerprint solution. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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