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Control de la formación de agregados H y J a través de la complejación huésped-huésped utilizando huéspedes de

Suresh Gadde¹, Elizabeth K Batchelor, Joshua P Weiss

¹Department of Chemistry and Center for Supramolecular Science, University of Miami, Coral Gables, Florida 33124-0431, USA.

Journal of the American Chemical Society

|November 15, 2008

Resumen

Cucurbit[7]uril (CB7) se une efectivamente a los colorantes de cianina pseudoisocianina (PIC) y pinacianol (PIN), interrumpiendo su agregación. Un invitado competidor, el 1-aminoadamantano (AD), permite el ajuste fino de esta interrupción de la agregación del tinte.

Área de la Ciencia:

Química supramolecular de las moléculas.
La fotofísica es la fotofísica.
Química computacional es la química computacional.

Sus antecedentes:

Los tintes de cianina como la pseudoisocianina (PIC) y el pinacianol (PIN) exhiben propiedades ópticas dependientes de la agregación.
Cucurbit[n]urils (CBs) son anfitriones macrocíclicos conocidos por su capacidad de atar a varios huéspedes.
Comprender las interacciones huésped-anfitrión es crucial para controlar la agregación de colorantes y el comportamiento óptico.

Objetivo del estudio:

Para investigar las interacciones de unión entre los tintes de cianina (PIC y PIN) y los huéspedes de cucurbit[n]uril (CB7 y CB6).
Para determinar el impacto de CB7 y CB6 en la agregación de colorantes.
Para explorar el uso de un invitado competidor para modular estas interacciones.

Principales métodos:

Se empleó la espectroscopia de absorción electrónica para estudiar los fenómenos de unión y agregación.
Se utilizaron métodos computacionales de teoría de densidad funcional (DFT) para modelar las interacciones huésped-huésped.
Se midieron las constantes de asociación de equilibrio (K) para cuantificar las afinidades de unión.

Principales resultados:

Cucurbit[7]uril (CB7) forma complejos más estables con PIC y PIN que el cucurbit[6]uril (CB6).
Los cálculos de DFT sugieren que la cavidad de CB6 es demasiado pequeña para acomodar a los huéspedes del tinte.
CB7 interrumpe efectivamente tanto los agregados J (PIC) como los agregados H/J (PIN).
Las constantes de asociación medidas para CB7 con PIC y PIN fueron 2,05 x 10^4 M^-1 y 3,84 x 10^5 M^-1, respectivamente.
El 1-aminoadamantano (AD), un fuerte aglutinante CB7 (K ≈ 10^12 M^-1), se utilizó para controlar la agregación del tinte.

Conclusiones:

CB7 es un huésped altamente efectivo para interrumpir la agregación del tinte de cianina.
El tamaño de la cavidad uril de la cucurbita juega un papel crítico en la unión de los huéspedes.
El uso de un invitado competidor como AD ofrece una estrategia para ajustar finamente los estados de agregación de tintes y las propiedades ópticas.

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