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241.
The title compound, (isopropylxanthato)(phenyl)mercury(I), was synthesized and characterized by elemental analysis, IR and thermogravimetric analysis. Density functional theory (DFT) method calculations were performed at B3LYP/CEP-121G and B3LYP/CEP-31G levels of theory, respectively. Vibrational frequencies were predicted, assigned, compared with the experimental values, and they are supported each other. The calculated results show that the strength of bond Hg—C is stronger than that of Hg—S, which is good agreement with the experimental data. The calculations of the second order optical nonlinearity and electronic absorption spectra are also performed. 相似文献
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243.
Margaret C. Gerthoffer Sikai Wu Bo Chen Tao Wang Steven Huss Shalisa M. Oburn Vincent H. Crespi John V. Badding Elizabeth Elacqua 《Chemical science》2020,11(42):11419
Limited supramolecular strategies have been utilized to synthesize sequence-defined polymers, despite the prominence of noncovalent interactions in materials design. Herein, we illustrate the utility of ‘sacrificial’ aryl-perfluoroaryl supramolecular synthons to synthesize sp3-hybridized nanothreads from sp2-enriched reactants. Our strategy features A–B reactant pairs in the form of a phenol:pentafluorophenol co-crystal that is preorganized for an electronically-biased and sequence-defined polymerization. The polymerization, initiated at 12 GPa, affords an alternating copolymer featuring exogenous –OH functionalities. The external substitution is confirmed through IR spectroscopy. Importantly, the inclusion of the functional unit provides the first experimental glimpse at reaction mechanism: keto–enol tautomerization that can only occur during cycloaddition is observed through IR spectroscopy. Our approach realizes the first example of a functionalized nanothread and attains sequence definition through sacrificial supramolecular preorganization and presents a further approach for de novo design of complex nanothreads.Supramolecular synthons are exploited to synthesize –OH functionalized sp3-rich sequence-defined nanothreads using pressure-induced polymerization of a phenol:pentafluorophenol co-crystal. 相似文献
244.
Jin Young Kim Kyung Hwa Cho Bo Young Jeong Chang Gyo Park Hoi Young Lee 《Experimental & molecular medicine》2020,52(7):1152
Rab coupling protein (RCP) is upregulated in head and neck squamous cell carcinoma (HNSCC) and is correlated with the progression and survival of patients. However, the role of RCP in one of the aggressive types of HNSCC, oral squamous cell carcinoma (OSCC), remains elusive. In the present study, we identified the important role of Zeb1 in RCP-induced OSCC epithelial-to-mesenchymal transition (EMT) and invasion. RCP induces Zeb1 expression, and silencing Zeb1 expression significantly inhibits RCP-induced OSCC invasion. In addition, Zeb1 upregulates MT1-MMP expression to promote OSCC EMT and invasion. Furthermore, we observed that the β1 integrin/EGFR/β-catenin signaling cascade mediates RCP-induced Zeb1 expression to promote OSCC invasion. Notably, we provide evidence that resveratrol (REV) strongly inhibits RCP-induced Zeb1 expression through blocking β1 integrin endosome recycling and EGFR activation, leading to suppression of RCP-induced OSCC invasion, demonstrating the important role of RCP in OSCC invasion and its reversion by REV. Collectively, the present study provides evidence for the first time that RCP aggravates OSCC invasion through increasing Zeb1 expression and subsequently upregulating MT1-MMP expression and that this process is reversed by REV, providing novel biomarkers and indicating the therapeutic potential of REV in OSCC.Subject terms: Oral cancer, Cell invasion 相似文献
245.
β-环糊精与两性表面活性剂相互作用 总被引:5,自引:0,他引:5
用表面张力法研究了β-环糊精与十一烷基酰胺甲酸钠(C11H23CONHCOONa,SF)两性表面活性剂在不同温度下的包结作用。结果表明:SF的表面张力值(β)及表观临界胶束浓度(cmc*)加入β-CD后增加,β-CD浓度越大,γ和cmc*增加越多,且SF的cmc*与β-CD浓度存在线性关系,随温度的升高,两性表面活性剂的表面张力值降低,意味着它们的表面活性随温度升高而增强。利用表面张力测定了β-CD-SF体系在不同温度下的包结形成常数Ka,进而求得了包结过程的焓变和熵变,结果表明,该过程是焓和熵均有利的过程,进一步说明疏水作用是形成包结物最重要的的作用力之一。 相似文献
246.
聚(C60 甲基丙烯酸甲酯)与聚(C60 苯乙烯)的THF溶液的透射光谱随浓度的增大而不断红移.这种异常的光谱位移可能与富勒烯的纳级(10-9)簇的形成有关.用简单的办法来“调改”一物质的性质是科学家们长期梦寐以求的,而含C60的聚合物正代表了这一群新奇的物质,它们的光学性质可以预期地和可逆地调变,只要简单改变一下浓度. 相似文献
247.
248.
The reaction of 7α-acetyl-6,14-endoethano-6,7,8,14-tetrahydrothebaine with 2-(thien-2-yl)ethylmagnesium bromide was investigated. The tertiary alcohol derivative 7α-[R-l-hydroxyl-l-methyl-3-(thien-2-yl)propyl])-6,14- endoethano-6,7,8,14-tetrahydrothebaine (3) and a by-product 4 were isolated. The structure of 4 was elucidated by X-ray analysis. The Grignard reaction shows high degree of stereoselectivity according with Cram rule. The crystal structure of 4 indicates that dihydrofuran ring was opened to form a phenolic hydroxyl group and a three-membered ring structure. It maintains the main rigid structure of morphine and contains a C(6)-C(14) enthano bridge. The 1-hydroxyl-1-methyl-3-(thien-2-yl)propyl group at C(7) position adopted S-configuration. 相似文献
249.
模糊正交法用于石墨炉探针原子化测定铋条件的研究 总被引:3,自引:0,他引:3
模糊正交法是通过把正交试验结果模糊化,然后用模糊数学的理论和方法来处理实验数据。与常规正交设计相比,能在同样实验工作量的情况下获得更多的信息。本文采用模糊正交法对元素Bi的测定条件进行优化,并将其同常规正交设计方差分析的结果进行了比较,并提出一个综合评价参数,对建立的分析方法进行了综合评价。 相似文献
250.
报道了用H_2Fe(CO)_4制备trans-Fe(CO)_3(PR_3)_2的新的羰基取代反应。在 过量质子存在下,H_2Fe(CO)_4中的羰基被活化,中心铁原子对膦的亲核进攻更为 敏感。在这种条件下H_2Fe(CO)_4与膦反应时,首先失去氢生成Fe(CO)_4(PR_3), Fe(CO)_4-(PR_3)再与第二个膦反应可高产率的得到trans-Fe(CO)_3(PR_3)_2。用 PPh_3与Fe(CO)_4(PPh_3)在过量质子存在下反应生成trans-Fe(CO)_3(PR_3)_2,证 实了上述过程。 相似文献