Hierarchical Self-Organization from Cyclic Peptide

The 19th International Electronic Conference on Synthetic Organic Chemistry session Polymer and Supramolecular ChemistryOur research group is implicated on the design and synthesis of supramolecular structures based on self-assembling cyclic peptides, particularly alpha,gamma-cyclic peptides (CPs). Most of these structures: dimer, nanotubes, fiber, etc, are based on beta-sheet type interactions. The CPs form structures that have allowed preparing a large variety of structures with applications in ion channels, electron and energy transfer process, molecular tweezers and so on. Here, we present the formation of spheres, hollow spheres, fibers, bars, etc. by a hierarchical supramolecular process from alpha,gamma-cyclic peptides with pyridine derivate ligands attached to one of its side chains, that additionally, are able to coordinate metals (Cu, Pd, etc.), entrap molecules, etc. which give to these structures a great potential for catalysis and drug deliver

Recent Advances in Controlling the Internal and External Properties of Self‐Assembling Cyclic Peptide Nanotubes and Dimers

One of the most powerful strategies for the preparation of nanotubes is based on the stacking of flat-shaped cyclic peptide components. This strategy allows precise control of the nanotube internal diameter, the external properties and, more recently, the structural characterisitics of the internal cavity. The recent advances in these technologies and the applications of the resulting materials are describedThis work was supported by the Spanish Agencia Estatal de Investigación (AEI) and the ERDF (CTQ2013‐43264‐R and CTQ2016‐78423‐R), and by the Xunta de Galicia and the ERDF (EM2014/011 and Centro singular de investigación de Galicia accreditation 2016‐2019, ED431G/09). N. R.‐V. thanks Mineco and the Gil Davila Foundation for her FPU contract and fellowship, respectively. We also thank the ORFEO‐CINCA network and Mineco (CTQ2016‐81797‐REDC)NO

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

Molecular Plumbing to Bend Self-Assembling Peptide Nanotubes

Light-induced molecular piping of cyclic peptide nanotubes to form bent tubular structures is described. The process is based on the [4+4] photocycloaddition of anthracene moieties, whose structural changes derived from the interdigitated flat disposition of precursors to the corresponding cycloadduct moieties, induced the geometrical modifications in nanotubes packing that provokes their curvature. For this purpose, we designed a new class of cyclic peptide nanotubes formed by β- and α-amino acids. The presence of the former predisposes the peptide to stack in a parallel fashion with the β-residues aligned along the nanotube and the homogeneous distribution of anthracene pendantsThis work was supported by the Spanish Agencia Estatal de Investigación (AEI) (CTQ2016-78423-R and PID2019-111126RB-100), the Xunta de Galicia (ED431C 2017/25 and Centro singular de Investigación de Galicia accreditation 2019–2022, ED431G 2019/03), and the European Union (European Regional Development Fund—ERDF). We also thank the ORFEO-CINCA network and Mineco (CTQ2016-81797-REDC, and RED2018-102331-T)S

3D printing of a palladium-alumina cermet monolithic catalyst: catalytic evaluation in microwave-assisted cross-coupling reactions

A straightforward manufacture strategy is proposed to obtain an efficient and robust palladium-alumina (Pd0/Al2O3) cermet monolithic catalyst, specifically designed to perform safe microwave assisted organic synthesis (MAOS). In this approach, a cermet catalyst with high surface area, controlled composition and adapted shape and dimensions to a microwave reactor vessel is generated via 3D printing technology and sintering. The resulting catalyst has been explored in heterogeneous Suzuki, Sonogashira, Stille and Heck cross-coupling reactions, in MAOS. The Pd0 catalyst is permanently active, stable, without leaching and can be recycled and reused at least 200 reaction cycles. The generation of hot spots, sparking or hazardous discharges is controlled by the effective immobilization of the palladium in the monolithic structure during the reaction. The palladium content is forming part of both the internal and external structure, providing greater mechanical resistance and catalytic activity with respect to the basic ceramic material (alumina)This work was financially supported by the Consellería de Cultura, Educación e Ordenación Universitaria of the Galician Government: EM2014/022 to A.C., ED431B2016/028 to F.G. The Strategic Grouping AEMAT grant No. ED431E2018/08 and the Spanish Ministry of Science, Innovation and Universities with grant No: MAT2017-90100-C2-1-P "MA thanks Xunta de Galicia and the ERDF (ED431C 2021/21)"S

Novel synthesis of platinum complexes and their intracellular delivery to tumor cells by means of magnetic nanoparticles

Platinum-based drugs are popular in clinics as chemotherapeutic agents to treat solid tumors

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

Anion recognition and induced self-assembly of an alpha,gamma-cyclic peptide to form spherical clusters

A cyclic octapeptide composed of hydroxy-functionalized γ-amino acids folds in a "V-shaped" conformation that allows the selective recognition of anions such as chloride, nitrate, and carbonate. The process involves the simultaneous self-assembly of six peptide subunits and the recognition of four anions to form a tetrahedral structure, in which the anions are located at the corners of the resulting structure. Each anion is coordinated to three different peptides. The structure was fully characterized by several techniques, including NMR spectroscopy and X-ray diffraction, and the material was able to facilitate the transmembrane transport of chloride ionsThis work was supported by the Spanish Ministry of Economy and Competitivity (MINECO) and the ERDF [CTQ2013-43264-R, CTQ2012-38543-C03-03], and by the Xunta de Galicia and the ERDF (GPC2013-039 and EM2014/011). N. R.-V. thanks MINECO for her FPU contract. We also thank ORFEO-CINCA network and MINECO (CTQ2014-51912-REDC). Technical support from the Unidade de Raios X, RIADT, USC, and especially to Antonio L. Llamas-Saiz is gratefully acknowledgedS

Self-assembling alfa,gamma-cyclic peptides that generate cavities with tunable properties

The design and synthesis of β-sheet-based self-assembling cyclic peptides with tunable cavities is described. The incorporation of a γ-amino acid with a hydroxyl group at C2 allows the incorporation of different groups that modify the internal properties of the resulting dimeric ensemble. These dimers can entrap different guests depending on the properties of the group at C2. The guest defines the geometry of the resulting aggregateThis work was supported by the Spanish Ministry of Economy and Competitivity (MINECO) and the ERDF (CTQ2010-15725 and CTQ2013-43264-R), and by the Xunta de Galicia and the ERDF (GPC2013-039, EM2012/117117 and EM2014/011011). N. R.-V. thanks MINECO for her FPU contract. We also thank the ORFEOCINCA network and MINECO (CTQ2014-51912-REDC) and the COST CM1306 European ActionS