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- Koshino, Masanori, et al.
(författare)
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Imaging the passage of a single hydrocarbon chain through a nanopore
- 2008
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Ingår i: Nature Nanotechnology. - : Springer Science and Business Media LLC. - 1748-3387 .- 1748-3395. ; 3:10, s. 595-597
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Tidskriftsartikel (refereegranskat)abstract
- Molecular transport through nanoscale pores in films, membranes and wall structures is of fundamental importance in a number of physical, chemical and biological processes(1-6). However, there is a lack of experimental methods that can obtain information on the structure and orientation of the molecules as they pass through the pore, and their interactions with the pore during passage. Imaging with a transmission electron microscope is a powerful method for studying structural changes in single molecules as they move(7,8) and for imaging molecules confined inside carbon nanotubes(9). Here, we report that such imaging can be used to observe the structure and orientation of a hydrocarbon chain as it passes through nanoscale defects in the walls of a single-walled carbon nanotube to the vacuum outside, and also to study the interactions between the chain and the nanopore. Based on experiments at 293 K and 4 K we conclude that the major energy source for the molecular motions observed at 4 K is the electron beam used for the imaging.
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| 2. |
- Solin, Niclas, et al.
(författare)
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An amphoteric mesoporous silica catalyzed aldol reaction
- 2009
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Ingår i: Catalysis communications. - : Elsevier BV. - 1566-7367 .- 1873-3905. ; 10:10, s. 1386-1389
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Tidskriftsartikel (refereegranskat)abstract
- A bi-functional mesoporous silica material, containing both carboxylic acid and amino groups, acts as a catalyst for the reaction between aldehydes and carbon nucleophiles. We demonstrate reaction conditions under which even aldehydes containing deactivating electron donating groups, or sterically demanding substituents, undergo the catalyzed reaction with acetone, affording primarily the condensation products. Moreover, we demonstrate that acetophenone and ethyl methyl ketone can replace acetone as nucleophile. The bi-functional mesoporous silica is a convenient catalyst, as it is simple to remove from the reaction media, thereby facilitating workup.
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