Self-assembly of thiolated cyanine aggregates on Au(111) and Au nanoparticle surfaces

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Heptamethinecyanine J-aggregates display sharp, intense fluorescence emission making them attractive candidates for developing a variety of chem-bio-sensing applications. They have been immobilized on planar thiol-covered Au surfaces and thiol-capped Au nanoparticles by weak molecular interactions....

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Detalles Bibliográficos
Autores principales: Menéndez, G.O., Cortés, E., Grumelli, D., Méndez De Leo, L.P., Williams, F.J., Tognalli, N.G., Fainstein, A., Vela, M.E., Jares-Erijman, E.A., Salvarezza, R.C.
Formato: JOUR
Materias:
Au nanoparticle
Au surfaces
Au(1 1 1 )
Au(111) surfaces
Bio-compatible systems
Biological applications
Electrochemical techniques
Fluorescence emission
J aggregates
Planar surface
PM-IRRAS
Substrate surface
Adsorption
Aggregates
Chemisorption
Monomers
Nanoparticles
Optical properties
Raman spectroscopy
Self assembly
Gold
cyanide
gold
nanomaterial
thiol derivative
article
chemistry
conformation
macromolecule
materials testing
particle size
surface property
ultrastructure
Cyanides
Macromolecular Substances
Materials Testing
Molecular Conformation
Nanostructures
Particle Size
Sulfhydryl Compounds
Surface Properties
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_20403364_v4_n2_p531_Menendez
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
Descripción
Sumario:Heptamethinecyanine J-aggregates display sharp, intense fluorescence emission making them attractive candidates for developing a variety of chem-bio-sensing applications. They have been immobilized on planar thiol-covered Au surfaces and thiol-capped Au nanoparticles by weak molecular interactions. In this work the self-assembly of novel thiolated cyanine (CNN) on Au(111) and citrate-capped AuNPs from solutions containing monomers and J-aggregates has been studied by using STM, XPS, PM-IRRAS, electrochemical techniques and Raman spectroscopy. Data show that CNN species adsorb on the Au surfaces by forming thiolate-Au bonds. We found that the J-aggregates are preferentially adsorbed on the Au(111) surface directly from the solution while adsorbed CNN monomers cannot organize into aggregates on the substrate surface. These results indicate that the CNN-Au interaction is not able to disorganize the large J-aggregates stabilized by π-π stacking to optimize the S-Au binding site but it is strong enough to hinder the π-π stacking when CNNs are chemisorbed as monomers. The optical properties of the J-aggregates remain active after adsorption. The possibility of covalently bonding CNN J-aggregates to Au planar surfaces and Au nanoparticles controlling the J-aggregate/Au distance opens a new path regarding their improved stability and the wide range of biological applications of both CNN and AuNP biocompatible systems. © 2012 The Royal Society of Chemistry.

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