In this study, the heteroatom classes and molecular structures of nitrogen compounds in vacuum residue arecharacterized by the electrospray ionization （ESI） Fourier transform ion cyclotron resonance mass spectromet...In this study, the heteroatom classes and molecular structures of nitrogen compounds in vacuum residue arecharacterized by the electrospray ionization （ESI） Fourier transform ion cyclotron resonance mass spectrometry （FT-ICRMS） combined with the Fourier transform infrared （FT-IR） spectroscopy. The results demonstrate that three basic nitrogencompounds, N1 （in which a molecule contains one nitrogen atom, similarly hereinafter）, N1O1 and N2, are identified bytheir positive-ion mass spectra, and three non-basic nitrogen compounds, N1, N1O1, and N1S1, are characterized by theirnegative-ion mass spectra. Among these nitrogen compounds, the N1 class species are the most predominant. Combinedwith the data of ESI FT-ICR MS and FT-IR, the basic N1 class species are likely alkyl quinolines, naphthenic quinolines,acridines, benzonacridines, while the abundant non-basic N1 class species are derivatives of benzocarbazole. In comparisonwith CGO, the N1 basic nitrogen compounds in VR exhibit a higher average degree of condensation and have much longeralkyl side chains.展开更多
While thiolate-protected Au nanoclusters （NCs） have drawn considerable interest in various fields, their poor stability in aqueous solution remains a major hurdle for practical applications. Here, we report a unique...While thiolate-protected Au nanoclusters （NCs） have drawn considerable interest in various fields, their poor stability in aqueous solution remains a major hurdle for practical applications. Here, we report a unique strategy based on ligand-shell engineering to improve the stability of thiolated Au NCs in solution. By employing two thiol-terminated ligands having oppositely charged functional groups on the surface of the NCs, we demonstrate that the electrostatic attraction between the oppositely charged functional groups of neighboring ligands could amplify the coordination among surface ligands, leading to the formation of pseudo-cage-like structures on the NC surface that could offer higher protection to the Au core in aqueous solution. The strategy developed in this study could be extended to toward practical applications. other metal NCs, further paving the way展开更多
文摘In this study, the heteroatom classes and molecular structures of nitrogen compounds in vacuum residue arecharacterized by the electrospray ionization （ESI） Fourier transform ion cyclotron resonance mass spectrometry （FT-ICRMS） combined with the Fourier transform infrared （FT-IR） spectroscopy. The results demonstrate that three basic nitrogencompounds, N1 （in which a molecule contains one nitrogen atom, similarly hereinafter）, N1O1 and N2, are identified bytheir positive-ion mass spectra, and three non-basic nitrogen compounds, N1, N1O1, and N1S1, are characterized by theirnegative-ion mass spectra. Among these nitrogen compounds, the N1 class species are the most predominant. Combinedwith the data of ESI FT-ICR MS and FT-IR, the basic N1 class species are likely alkyl quinolines, naphthenic quinolines,acridines, benzonacridines, while the abundant non-basic N1 class species are derivatives of benzocarbazole. In comparisonwith CGO, the N1 basic nitrogen compounds in VR exhibit a higher average degree of condensation and have much longeralkyl side chains.
文摘While thiolate-protected Au nanoclusters （NCs） have drawn considerable interest in various fields, their poor stability in aqueous solution remains a major hurdle for practical applications. Here, we report a unique strategy based on ligand-shell engineering to improve the stability of thiolated Au NCs in solution. By employing two thiol-terminated ligands having oppositely charged functional groups on the surface of the NCs, we demonstrate that the electrostatic attraction between the oppositely charged functional groups of neighboring ligands could amplify the coordination among surface ligands, leading to the formation of pseudo-cage-like structures on the NC surface that could offer higher protection to the Au core in aqueous solution. The strategy developed in this study could be extended to toward practical applications. other metal NCs, further paving the way
