Self‐assembling Venturi‐like peptide nanotubes

We describe the design and synthesis of self-assembling peptide nanotubes that have an internal filter area and whose length and internal diameters, at the entrance and in the constricted area, are precisely controlledThis work was supported by the Spanish Ministry of Economy and Competitivity (Mineco) and the ERDF (CTQ2013‐43264‐R), and by the Xunta de Galicia and the ERDF (EM2014/011). A. F. and H. L. O. thank Mineco for their FPU contracts. We also thank the ORFEO‐CINCA network and Mineco (CTQ2014‐ 51912‐REDC). We very much appreciate Dr. Ignacio Alfonso (IQAC‐CSIC) for his help in designing DOSY experimentsNO

The effect of host structure on the selectivity and mechanism of supramolecular catalysis of Prins cyclizations.

The effect of host structure on the selectivity and mechanism of intramolecular Prins reactions is evaluated using K12Ga4L6 tetrahedral catalysts. The host structure was varied by modifying the structure of the chelating moieties and the size of the aromatic spacers. While variation in chelator substituents was generally observed to affect changes in rate but not selectivity, changing the host spacer afforded differences in efficiency and product diastereoselectivity. An extremely high number of turnovers (up to 840) was observed. Maximum rate accelerations were measured to be on the order of 105, which numbers among the largest magnitudes of transition state stabilization measured with a synthetic host-catalyst. Host/guest size effects were observed to play an important role in host-mediated enantioselectivity

Diseño y síntesis de cápsulas moleculares y sistemas mesógenos basados en ciclopéptidos

Las contenedores moleculares y los materiales porosos nanoestructurados han emergido como sistemas altamente interesantes con aplicaciones en química, la nanotecnología y la ciencia de materiales. Uno de los métodos más eficaces para obtener este tipo de estructuras consiste en la asociación de moléculas pequeñas mediante interacciones supramoleculares. Teniendo en cuenta estas consideraciones, en esta tesis doctoral se describe el diseño, la síntesis y el estudio de las propiedades de sistemas mesógenos y cápsulas autoensambladas a partir de ciclopéptidos convenientemente modificados. De este modo, en la primera parte, se abordó la preparación de materiales porosos usando moléculas discóticas formadas por un ciclopéptido central decorado con dendrones, que portan un número variable de colas alquílicas. Para la formación de la molécula discótica se propusieron dos estrategias: la covalente, en la cual el péptido y los dendrones se unen mediante enlaces covalentes, y la supramolecular, en la que ambos componentes interaccionan a través de enlaces de hidrógeno. Por otro lado, en la segunda parte, nos centramos en la preparación de cápsulas moleculares provistas de grupos con capacidad de actuar como directores de la encapsulación proyectados hacia la cavidad interna a partir de α,γ-ciclopéptidos. Con este propósito, las estructuras peptídicas se modificaron con tapas moleculares apropiadas para promover la internalización de distintas moléculas huésped en el interior del receptor

Péptidos cíclicos y su utilización en materiales poliméricos supramoleculares

Tubular structures play an important role in important biologic processes for life. Cyclic peptide nanotubes were widely studied over the last years. The synthetic simplicity and the ease to control its diameter and properties make this strategy an attractive tool to achieve new functional materials. In this communication we summarize the main features and recent research on this field, focusing on α,γ-cyclic peptide nanotubes, due to their high association constants and ability to modulate properties of the internal cavity.Las estructuras tubulares juegan un papel crucial en procesos biológicos fundamentales para la vida. Inspirados en ellas, los nanotubos ciclopeptídicos han sido objeto de un profundo estudio en las últimas décadas. La sencillez sintética, unida al control preciso del diámetro y sus propiedades, han hecho de esta estrategia una ruta atractiva para la obtención de nuevos materiales funcionales. En este artículo se recogen los aspectos más destacados y los últimos avances en este campo, focalizándose principalmente en los nanotubos α,γ- ciclopeptídicos debido a sus altas constantes de asociación y la posibilidad de controlar las propiedades internas del poro

Self-assembling molecular capsules based on alpha, gamma-Cyclic peptides

A new capsule based on a β-sheet self-assembling cyclic peptide with the ability to recognize and release several guests is described. The host structure is composed of two self-complementary α,γ-cyclic peptides bearing a Zn porphyrin cap that is used for the selective recognition of the guest. The two components are linked through two dynamic covalent bonds. The combination of binding forces, including hydrogen bonding, metal coordination, and dynamic hydrazone bonds, allows the reversible recognition of long bipyridine guests. The affinity for these ligands showed a strong dependence on the guest length. Delivery of the encapsulated ligand can be achieved by hydrolysis of hydrazones to disrupt the sandwich complex structureH. L. O. thanks Mineco for his FPU contract and the Diputación de A Coruña for his research fellowship. We also thank the ORFEO-CINCA networkNO

Self-Assembling Molecular Capsules Based on α,γ-Cyclic Peptides

A new capsule based on a β-sheet self-assembling cyclic peptide with the ability to recognize and release several guests is described. The host structure is composed of two self-complementary α,γ-cyclic peptides bearing a Zn porphyrin cap that is used for the selective recognition of the guest. The two components are linked through two dynamic covalent bonds. The combination of binding forces, including hydrogen bonding, metal coordination, and dynamic hydrazone bonds, allows the reversible recognition of long bipyridine guests. The affinity for these ligands showed a strong dependence on the guest length. Delivery of the encapsulated ligand can be achieved by hydrolysis of hydrazones to disrupt the sandwich complex structure