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Reacciones de intercambio entre alcanetiolados y alcaneselenolos en Au{111}

J Nathan Hohman¹, John C Thomas, Yuxi Zhao

¹California NanoSystems Institute and Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States.

Journal of the American Chemical Society

|May 8, 2014

Resumen

Las monocapas autoensambladas de alcanetiolados sobre el oro son rápidamente reemplazadas por alcaneselenolos, formando nuevas estructuras. La microscopía de túnel de barrido revela que las moléculas pueden intercambiar posiciones en la superficie del oro.

Área de la Ciencia:

Ciencias de la superficie Ciencias de la superficie.
Nanotecnología La nanotecnología es la nanotecnología.
Ciencia de los materiales ciencia de los materiales.

Sus antecedentes:

Las monocapas autoensambladas (SAM) son ensamblajes moleculares ordenados en superficies.
Los alcanetiolatos sobre el oro (Au{111}) forman SAMs bien definidos.
Las reacciones de intercambio son cruciales para modificar las propiedades de la superficie.

Objetivo del estudio:

Para investigar el intercambio de SAMs alkanethiolate con alkaneselenols en Au{111}.
Para caracterizar la evolución estructural durante el proceso de intercambio.
Para explorar la dinámica de las interacciones molécula-oro utilizando microscopía de túnel de barrido.

Principales métodos:

Formación de SAMs de alcanetiolato en el Au{111}.
Inmersión de SAMs en soluciones de alkaneselenol.
Microscopía de túnel de barrido in situ (STM) para el análisis estructural y dinámico.
Análisis de la cinética del crecimiento de las islas.

Principales resultados:

Sustitución rápida y completa de los tiolatos por selenolatos.
La estructura monocapa hace transiciones de tipo tiolato a tipo selenolato con una cobertura cada vez mayor.
Evidencia de la fijación de selenolato de oro lábil a temperatura ambiente y sesgo de muestra positivo.
Se observaron reacciones de intercambio de posiciones moleculares inducidas por la sonda STM.

Conclusiones:

El proceso de intercambio sigue una cinética de crecimiento de la isla dependiente del perímetro.
La transformación estructural de las SAM se produce durante la incorporación del selenolato.
STM puede inducir y sondear el intercambio molecular dinámico en superficies.
Comprender estas dinámicas es clave para diseñar superficies funcionalizadas.

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