相关实验视频

Updated: May 5, 2026

In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions
10:22

In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions

Published on: June 16, 2014

17.1K

Au25(SR) 18 的半环化学:碎片化途径和催化活性位点

Chunyan Liu1, Sisi Lin, Yong Pei

  • 1Department of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, Xiangtan University , Xiangtan, Hunan Province, P. R. China 411105.

Journal of the American Chemical Society
|November 21, 2013
PubMed
概括

密度函数理论的计算揭示了金 (Au25(SR) 18的逐步碎片化机制,解释了稳定的Au21(SR) 14和Au17(SR) 10碎片的形成. 这项研究确定了主 motif 中的黄金原子作为 styrene 氧化活性场所.

更多相关视频

A Novel Technique for Raman Analysis of Highly Radioactive Samples Using Any Standard Micro-Raman Spectrometer07:52

A Novel Technique for Raman Analysis of Highly Radioactive Samples Using Any Standard Micro-Raman Spectrometer

Published on: April 12, 2017

15.6K
Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry09:37

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry

Published on: October 18, 2019

10.0K

相关概念视频

Mass Spectrometry: Molecular Fragmentation Overview01:20

Mass Spectrometry: Molecular Fragmentation Overview

The ionization of a molecule into a molecular ion inside the mass spectrometer causes instability in the molecule's structure due to the loss of an electron. This eventually leads to the fragmentation or breaking of some bonds in the molecule. The fragmentation occurs predominantly at specific bonds to yield relatively stable fragments.
One type of fragmentation pattern is the cleavage of a single bond in the molecular ion. The cleavage leads to a radical and a cation. The cleavage can occur at...
5.2K
Mass Spectrometry: Alkyne Fragmentation00:53

Mass Spectrometry: Alkyne Fragmentation

The fragmentation of alkynes preferentially occurs at the carbon–carbon bond between the α and β carbon of the alkyne bond to generate a 3-propynyl cation (or propargyl cation). In terminal alkynes, there is the only type of fragmentation that yields the 3-propynyl cation. The unsubstituted 3-propynyl cation exhibits a peak at a mass-to-charge ratio of 39. In internal alkynes, the 3-propynyl cation is substituted. For example, 2-pentyne fragments into methyl-substituted...
2.1K
Mass Spectrometry of Amines01:15

Mass Spectrometry of Amines

In mass spectroscopy, amines undergo fragmentation to give parent ions with odd molecule weights. This observed mass spectrum follows the nitrogen rule; a molecule with an odd number of nitrogen atoms produces a molecular ion with an odd molecular weight. Amines undergo fragmentation through α cleavage, producing nitrogen-containing cations—iminium ions—and alkyl radicals. Mass spectra of aromatic and cyclic aliphatic amines exhibit strong molecular ion peaks, but acyclic...
3.9K
Mass Spectrometry: Alkene Fragmentation00:59

Mass Spectrometry: Alkene Fragmentation

Alkenes lose one electron from the unsaturated π bond upon ionization and form stable molecular ions. Further fragmentation of alkenes occurs through three different reaction pathways. The most prominent fragmentation is the cleavage at the allylic position. The resultant allylic carbocation is resonance stabilized. In the mass spectra of terminal alkenes, this fragment appears at a mass-to-charge ratio of 41. In the internal alkenes, where there are two choices of allylic cleavage, the...
3.8K
Mass Spectrometry: Carboxylic Acid, Ester, and Amide Fragmentation01:01

Mass Spectrometry: Carboxylic Acid, Ester, and Amide Fragmentation

The fragmentation patterns observed for compounds such as carboxylic acids, esters, and amides in the mass spectra include ⍺-cleavage and McLafferty rearrangement. Fragmentation by ⍺-cleavage preferentially occurs at the carbon-carbon bond at the ⍺-position next to the carboxylic group to generate a neutral radical and a cation. Long chain compounds with hydrogen at their γ-carbon undergo McLafferty rearrangement to give a radical cation and a neutral alkene.
For example,...
2.6K
Mass Spectrometry: Cycloalkene Fragmentation00:54

Mass Spectrometry: Cycloalkene Fragmentation

The molecular ions of cycloalkenes undergo fragmentation via a retro-Diels–Alder reaction.
1.5K