Functionalized Au22 clusters: synthesis, characterization, and patterning.
ACS Appl Mater Interfaces
; 1(10): 2199-210, 2009 Oct.
Article
en En
| MEDLINE
| ID: mdl-20355854
ABSTRACT
We synthesized fluorescent, porphyrin-anchored, Au(22) clusters in a single step, starting from well-characterized Au(25) clusters protected with glutathione (-SG) by a combined core reduction/ligand exchange protocol, at a liquid-liquid interface. The prepared cluster was characterized by UV/vis, photoluminescence, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy, elemental analysis, and matrix-assisted laser desorption ionization mass spectrometry. The absence of a 672 nm intraband transition of Au(25) and the simultaneous emergence of new characteristic peaks at 520 and 635 nm indicate the formation of the Au(22) core. An increase in the binding energy of 0.4 eV in Au 4f core-level peaks confirmed the presence of a reduced core size. Quantitative XPS confirmed the Au/S ratio. The presence of a free base, tetraphenylporphyrin (H(2)TPPOAS-), on the Au(22) core was confirmed by fluorimetric titrations with Cu(2+) and Zn(2+) ions. From all of these, the composition of the cluster was determined to be Au(22)[(-SG)(15)(-SAOPPTH(2))(2)], which was supported by mass spectrometry and elemental analysis. We utilized the fluorescence nature of these water-soluble clusters for the fabrication of fluorescent patterns by soft lithography. The patterns were studied using tapping-mode atomic force microscopy and confocal fluorescence imaging.
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Base de datos:
MEDLINE
Idioma:
En
Revista:
ACS Appl Mater Interfaces
Asunto de la revista:
BIOTECNOLOGIA
/
ENGENHARIA BIOMEDICA
Año:
2009
Tipo del documento:
Article
País de afiliación:
India