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231223s2009 xx |||||o 00| ||eng c |
| 024 |
7 |
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|a 10.1021/la9013174
|2 doi
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|a pubmed24n0635.xml
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|a (DE-627)NLM190360348
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|a (NLM)19645476
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|a DE-627
|b ger
|c DE-627
|e rakwb
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| 041 |
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|a eng
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| 100 |
1 |
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|a Ha, Jeong-Myeong
|e verfasserin
|4 aut
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| 245 |
1 |
0 |
|a Synthesis and characterization of accessible metal surfaces in calixarene-bound gold nanoparticles
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| 264 |
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1 |
|c 2009
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| 336 |
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|a Text
|b txt
|2 rdacontent
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|a ƒaComputermedien
|b c
|2 rdamedia
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|a ƒa Online-Ressource
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|2 rdacarrier
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| 500 |
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|a Date Completed 04.12.2009
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| 500 |
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|a Date Revised 08.09.2009
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|a published: Print
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|a Citation Status PubMed-not-MEDLINE
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| 520 |
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|a Use of organic ligands to partially passivate nanoparticles against sintering yet retain a degree of small molecule accessibility to the metal surface has been a lofty goal in functional materials synthesis, which in principle also enables the design of preferred electronic and steric environments on a nanoparticle surface. Catalysis using gold in particular requires donor ligands that facilitate an electron-rich metal surface and generalizable strategies for dealing with deactivation due to sintering. Here, synthesis and characterization of gold nanoparticles postsynthetically modified with the chelating ligand cone-5,11,17,23,29,35-hexa(tert-butyl)-37,39,41-tris(diphenylphosphinomethoxy)-38,40,42-trimethoxycalix[6]arene (1) is reported. In solution as well as when supported on the surface of TiO2, nanoparticles modified with tripodal calix[6]arene phosphine ligand 1 demonstrate enhanced protection against sintering relative to unmodified, tetraoctylammonium bromide-surfactant-stabilized gold nanoparticles. In between adsorbed calixarene ligands, there is accessible gold surface area in these nanoparticles, and this is measured quantitatively for the first time for a calixarene-modified nanoparticle, using a newly developed fluorescence methodology involving 2-naphthalenethiol as a relevant chemisorption probe molecule. Ligand steric bulk critically influences amount of accessible surface on the metal nanoparticle since the use of a smaller calix[4]arene ligand (MBC) results in a 7-fold lower accessible surface area relative to using 1 under otherwise similar conditions. In addition, surface coverage of 1 controls accessible surface area in an unintuitive fashion: a 4-fold increase in accessible metal surface area is observed upon increasing the surface coverage of 1 to be 1.5-fold higher than the minimum required for surface saturation. This is presumably the result of a more open ligand packing of 1 at higher surface coverages, which allows greater accessibility to 2-napthalenethiol
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| 650 |
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4 |
|a Journal Article
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| 700 |
1 |
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|a Solovyov, Andrew
|e verfasserin
|4 aut
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| 700 |
1 |
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|a Katz, Alexander
|e verfasserin
|4 aut
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| 773 |
0 |
8 |
|i Enthalten in
|t Langmuir : the ACS journal of surfaces and colloids
|d 1992
|g 25(2009), 18 vom: 15. Sept., Seite 10548-53
|w (DE-627)NLM098181009
|x 1520-5827
|7 nnns
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| 773 |
1 |
8 |
|g volume:25
|g year:2009
|g number:18
|g day:15
|g month:09
|g pages:10548-53
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| 856 |
4 |
0 |
|u http://dx.doi.org/10.1021/la9013174
|3 Volltext
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|d 25
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|h 10548-53
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