While Raman spectroscopy is a useful method for analyzing many organic compounds, it is limited by relatively low sensitivity. Therefore, Surface Enhanced Raman Spectroscopy (SERS) based on the adsorption of organic a...While Raman spectroscopy is a useful method for analyzing many organic compounds, it is limited by relatively low sensitivity. Therefore, Surface Enhanced Raman Spectroscopy (SERS) based on the adsorption of organic analytes onto gold or silver nanostructures has been used to enhance the signal of chemicals presented at very low concentrations. Although the plasmonic effect of SERS has been shown to play a large role in signal enhancement, the significance of the chemical effect due to the analyte chemisorption on the gold or silver surface is less well understood. In this study, the role of aniline substituents is examined by probing the SERS intensities of various anilines in silver and gold colloids using a Raman spectrometer with an excitation wavelength of 785 nm. The SERS enhancement factors and detection limits for aniline and its mono- and di-substituted ortho derivatives are determined and compared. Both the steric requirements of chemisorption and the inductive effects of electron-withdrawal due to the substituents affect the signal intensities of various vibrational modes of the amino group and the aromatic ring. The degree of enhancement is also related to the methods for preparing the silver and gold colloids, which are characterized by probing the nanoparticle morphology and its degree of aggregation using transmission electron microscopy (TEM).展开更多
In order to look for novel insecticides containing N-pyridylpyrazole, ten novel pyrazolecarboxamides containing different ortho-substituents in the aniline part were synthesized, and their structures were characterize...In order to look for novel insecticides containing N-pyridylpyrazole, ten novel pyrazolecarboxamides containing different ortho-substituents in the aniline part were synthesized, and their structures were characterized by 1H NMR, 13C NMR and HRMS. The single crystal structure of 10b was determined by X-ray diffraction. Their evaluated insecticidal activity against oriental armyworm （Mythimna separata） indicated that all the compounds exhibited moderate insecticidal activities.展开更多
文摘While Raman spectroscopy is a useful method for analyzing many organic compounds, it is limited by relatively low sensitivity. Therefore, Surface Enhanced Raman Spectroscopy (SERS) based on the adsorption of organic analytes onto gold or silver nanostructures has been used to enhance the signal of chemicals presented at very low concentrations. Although the plasmonic effect of SERS has been shown to play a large role in signal enhancement, the significance of the chemical effect due to the analyte chemisorption on the gold or silver surface is less well understood. In this study, the role of aniline substituents is examined by probing the SERS intensities of various anilines in silver and gold colloids using a Raman spectrometer with an excitation wavelength of 785 nm. The SERS enhancement factors and detection limits for aniline and its mono- and di-substituted ortho derivatives are determined and compared. Both the steric requirements of chemisorption and the inductive effects of electron-withdrawal due to the substituents affect the signal intensities of various vibrational modes of the amino group and the aromatic ring. The degree of enhancement is also related to the methods for preparing the silver and gold colloids, which are characterized by probing the nanoparticle morphology and its degree of aggregation using transmission electron microscopy (TEM).
基金Project supported by the National Basic Research Program of China （No. 2010CB126106） and the National Natural Science Foundation of China （No. 20872069）
文摘In order to look for novel insecticides containing N-pyridylpyrazole, ten novel pyrazolecarboxamides containing different ortho-substituents in the aniline part were synthesized, and their structures were characterized by 1H NMR, 13C NMR and HRMS. The single crystal structure of 10b was determined by X-ray diffraction. Their evaluated insecticidal activity against oriental armyworm （Mythimna separata） indicated that all the compounds exhibited moderate insecticidal activities.
