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1.
Angew Chem Int Ed Engl ; : e202413629, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39225451

RESUMO

Helical foldamers have attracted much attention over the last decades given their resemblance to certain biomacromolecules and their potential in domains as different as pharmaceutics, catalysis and photonics. Various research groups have successfully controlled the right- or left- handedness of these oligomers by introducing stereogenic centers through covalent or non-covalent chemistry. However, developing helical structures whose handedness can be reversibly switched remains a major challenge for chemists. To date, such an achievement has been reported with light-responsive single-stranded foldamers only. Herein, we demonstrate that grafting a unidirectional motor onto foldamer strands constitutes a relevant strategy to i) control the single or double helical state of a foldamer, ii) switch on the chiral induction process from the motor to the helical strands and iii) select the handedness of double helical structures through photochemical and thermal stimulations.

2.
Angew Chem Int Ed Engl ; : e202413616, 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39163166

RESUMO

This study reports the serendipitous discovery of intermolecular anionic mixed-valence (MV) and π-dimer species in ortho-pentannulated BisAzaCoroneneDiimides (BACDs) during their electrochemical reduction in a non-aqueous solvent. A library of nitrogen-containing extended PDIs was synthesized via an aza-benzannulation reaction followed by a Pd-catalysed ortho-pentannulation reaction. Ortho-pentannulated BACDs revealed strong aggregation abilities in solution. Concentration-dependent UV-vis absorption spectra, variable temperature 1H NMR experiments, and atomic force microscopy coupled to molecular dynamics support their self-assembly into columnar aggregates. Cyclic voltammetry experiments in dichloromethane reveal prominent splitting of the first reduction wave, attributed to the formation of unprecedented intermolecular anionic MV and π-dimers in organic solvent. These species were thoroughly characterized by real-time spectroelectrochemistry, electrochemical simulations and theoretical calculations. Remarkably, this work underscores the tuneable nature of AzaBenzannulatedPerylene Diimides (AzaBPDIs) and BACDs, emphasizing their potential as a promising scaffold for designing supramolecular materials with long-range radical anion delocalization. The observation of this phenomenon provides insights into the fundamental behaviour of supramolecular organic semiconductors, thereby paving the way for the development of novel electronic devices and electron-deficient materials.

3.
Angew Chem Int Ed Engl ; 63(15): e202400961, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38284742

RESUMO

Incorporating chiral elements in host-guest systems currently attracts much attention because of the major impact such structures may have in a wide range of applications, from pharmaceuticals to materials science and beyond. Moreover, the development of multi-responsive and -functional systems is highly desirable since they offer numerous benefits. In this context, we describe herein the construction of a metal-driven self-assembled cage that associates a chiral truxene-based ligand and a bis-ruthenium complex. The maximum separation between both facing chiral units in the assembly is fixed by the intermetallic distance within the lateral bis-ruthenium complex (8.4 Å). The resulting chiral cavity was shown to encapsulate polyaromatic guest molecules, but also to afford a chiral triply interlocked [2]catenane structure. The formation of the latter occurs at high concentration, while its disassembly could be achieved by the addition of a planar achiral molecule. Interestingly the planar achiral molecule exhibits induced circular dichroism signature when trapped within the chiral cavity, thus demonstrating the ability of the cage to induce supramolecular chirogenesis.

4.
Chemistry ; 27(64): 15922-15927, 2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34478209

RESUMO

The development of methodologies to control on demand and reversibly supramolecular transformations from self-assembled metalla-structures requires the rational design of architectures able to answer to an applied stimulus. While solvent or concentration changes, light exposure or addition of a chemical have been largely explored to provide these transformations, the case of pH sensitive materials is less described. Herein, we report the first example of a pH-triggered dissociation of a coordination-driven self-assembled interlocked molecular link. It incorporates a pH sensitive benzobisimidazole-based ligand that can be selectively protonated on its bisimidazole moieties. This generates intermolecular electrostatic repulsions that reduces drastically the stability of the interlocked structure, leading to its dissociation without any sign of protonation of the pyridine moieties involved in the coordination bonds. Importantly, the dissociation process is reversible through addition of a base.


Assuntos
Ligantes , Concentração de Íons de Hidrogênio , Solventes , Eletricidade Estática
5.
ACS Nano ; 15(2): 2569-2577, 2021 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-33512151

RESUMO

Janus nanocylinders exhibit nanometric dimensions, a high aspect ratio, and two faces with different chemistries (Janus character), making them potentially relevant for applications in optics, magnetism, catalysis, surface nanopatterning, or interface stabilization, but they are also very difficult to prepare by conventional strategies. In the present work, Janus nanocylinders were prepared by supramolecular coassembly in water of two different polymers functionalized with complementary assembling units. The originality of our approach consists in combining charge transfer complexation between electron-rich and electron-poor units with hydrogen bonding to (1) drive the supramolecular formation of one-dimensional structures (cylinders), (2) force the two polymer arms on opposite sides of the cylinders independently of their compatibility, resulting in Janus nanoparticles, and (3) detect coassembly through a color change of the solution upon mixing of the functional polymers.

6.
Chemistry ; 27(7): 2410-2420, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33175405

RESUMO

Two-component organogels and xerogels based on a C3 -symmetric pyrene-containing gelator have been deeply characterized through a wide range of techniques. Based on the formation of charge transfer complexes, the gelation phenomenon proved to be highly dependent on the nature of the electron poor dopant. This parameter significantly influenced the corresponding gelation domains, the critical gelation concentrations of acceptor dopants, the gel-to-sol transition temperatures, the microstructures formed in the xerogel state and their spectroscopic properties. In particular, titrations and variable-temperature UV-visible absorption spectroscopy demonstrated the key role of donor-acceptor interactions with a remarkable correlation between the phase transition temperatures and the disappearance of the characteristic charge transfer bands. The assignment of these electronic transitions was confirmed through time-dependent density functional theory (TD-DFT) calculations. Eventually, it was shown that the luminescent properties of these materials can be tuned with the temperature, either in intensity or emission wavelength.

7.
Chem Commun (Camb) ; 56(20): 3077-3080, 2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-32051981

RESUMO

A glycoluril-based molecular clip incorporating two tetrathiafulvalene (TTF) sidewalls has been synthesized using a straightforward Diels-Alder synthetic route and its ability to self-assemble with fullerene C60 in a 2 : 1 stoichiometry has been demonstrated in solution.

8.
Colloids Surf B Biointerfaces ; 188: 110816, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31991290

RESUMO

Nanoparticles (NPs) based on biocompatible and biodegradable polymers such as poly(lactic-co-glycolic acid) (PLGA) and polycaprolactone (PCL) represent effective systems for systemic drug delivery. Upon injection into the blood circuit, the NP surface is rapidly modified due to adsorption of proteins that form a 'protein corona' (PC). The PC plays an important role in cellular targeting, uptake and NP bio-distribution. Hence, the study of interactions between NPs and serum proteins appears as key for biomedical applications and safety of NPs. In the present work, we report on the comparative protein fluorescence quenching extent, thermodynamics of protein binding and identification of proteins in the soft and hard corona layers of PLGA and PCL NPs. NPs were prepared via a single emulsion-solvent evaporation technique and characterized with respect to size, zeta potential, surface morphology and hydrophobicity. Protein fluorescence quenching experiments were performed against human serum albumin. The thermodynamics of serum protein binding onto the NPs was studied using isothermal titration calorimetry. Semi-quantitative analysis of proteins in the PC layers was conducted using gel electrophoresis and mass spectrometry using human serum. Our results demonstrated the influence of particle hydrophobicity on the thermodynamics of protein binding. Human serum proteins bind to a greater extent and with greater affinity to PCL NPs than PLGA NPs. Several proteins were detected in the hard and soft corona of the NPs, representing their unique proteome fingerprints. Some proteins were unique to the PCL NPs. We anticipate that our findings will assist with rational design of polymeric NPs for effective drug delivery applications.


Assuntos
Nanopartículas/química , Poliésteres/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Albumina Sérica Humana/química , Termodinâmica , Adsorção , Humanos , Tamanho da Partícula , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/sangue , Propriedades de Superfície
9.
Angew Chem Int Ed Engl ; 59(2): 716-720, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31670452

RESUMO

Developing methodologies for on-demand control of the release of a molecular guest requires the rational design of stimuli-responsive hosts with functional cavities. While a substantial number of responsive metallacages have already been described, the case of coordination-tweezers has been less explored. Herein, we report the first example of a redox-triggered guest release from a metalla-assembled tweezer. This tweezer incorporates two redox-active panels constructed from the electron-rich 9-(1,3-dithiol-2-ylidene)fluorene unit that are facing each other. It dimerizes spontaneously in solution and the resulting interpenetrated supramolecular structure can dissociate in the presence of an electron-poor planar unit, forming a 1:1 host-guest complex. This complex dissociates upon tweezer oxidation/dimerization, offering an original redox-triggered molecular delivery pathway.

10.
Chem Commun (Camb) ; 55(58): 8426-8429, 2019 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-31259345

RESUMO

The synthesis of a redox-active helical foldamer and its immobilization onto a gold electrode are described. These large molecular architectures are grafted in a reproducible manner and provide foldamer-based self-assembled monolayers displaying recognition properties.

11.
Chem Commun (Camb) ; 55(64): 9519-9522, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31329201

RESUMO

Naphthalene-diimide (NDI)-containing nanocylinders were formed by supramolecular self-assembly in water through cooperative hydrogen bonds between bis(urea) units, reinforced by hydrophobic and aromatic-stacking interactions. The nanocylinders, decorated with poly(ethylene oxide) arms ensuring their solubility in water, exhibit a huge aspect ratio (diameter 13 nm, length 300 nm) and are extremely stable.

12.
Chem Commun (Camb) ; 55(40): 5743-5746, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31038524

RESUMO

Tetrathiafulvalene redox units were grafted at both extremities of an oligopyridine-dicarboxamide foldamer through a straightforward copper-catalyzed azide-alkyne cycloaddition. The present work demonstrates that the hybridization equilibrium of foldamers can be tuned through redox stimulations.

13.
Chem Soc Rev ; 47(15): 5614-5645, 2018 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-30033473

RESUMO

Tetrathiafulvalene (TTF) has been extensively explored as a π-electron donor in supramolecular systems. Over the last two decades substantial advances have been made in terms of constructing elaborate architectures based on TTF and in exploiting the resulting systems in the context of supramolecular host-guest recognition. The inherent electron-donating character of TTF derivatives has led to their use in the construction of highly efficient optoelectronic materials, optical sensors, and electron-transfer ensembles. TTFs are also promising candidates for the development of the so-called "functional materials" that might see use in a range of modern technological applications. Novel synthetic strategies, coupled with the versatility inherent within the TTF moiety, are now allowing the architecture of TTF-based systems to be tuned precisely and modified for use in specific purposes. In this critical review, we provide a "state-of-the-art" overview of research involving TTF-based macrocyclic systems with a focus on their use in supramolecular host-guest recognition, as components in non-covalent electron transfer systems, and in the construction of "molecular machines".

14.
Org Biomol Chem ; 16(14): 2470-2478, 2018 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-29561017

RESUMO

The present work takes advantage of the self-assembly process occurring along organogelation, to organize Second Harmonic Generation (SHG) active chromophores. To do so, three push-pull chromophores endowed with a dodecyl urea chain were synthesized and characterized. Their organogelating properties were studied in a wide range of solvents. Despite similar architectures, these derivatives exhibit very different gelling properties, from supergelation to the absence of gelling ability. The utilization of the Hansen solubility parameters allows for observing clear relationships between the gelled solvents and critical gelation concentrations. By evaporating the solvents from the organogels, xerogel materials were prepared and systematically studied by means of optical and electron microscopy as well as SHG microscopy. These studies demonstrate the critical role of the solvent over material structuring and allow generalizing the approach exploiting organogelation as a structuring tool to spontaneously organize push-pull chromophores into SHG-active materials.

15.
Soft Matter ; 12(41): 8480-8484, 2016 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-27722741

RESUMO

A study of the structural parameters which govern the supramolecular organization of an organogelator built from the Disperse Red moiety is proposed. In particular, the key balance between intermolecular H-bonding and/or π-π interactions is addressed by comparing the effect of a secondary amide vs. an ester linker within the molecular structure. Solution 1H-NMR studies show the superiority of the former interaction in promoting the nanostructuring process, allowing it to reach a gel state in toluene. The nanostructures obtained from both the amide and the ester derivatives were also studied in the solid state. In particular, the use of second-harmonic generation microscopy demonstrates that an anisotropic organization of the material can even be observed in the case of the ester derivative, which demonstrates the efficiency of the tris(alkoxy)benzene unit in directing the self-assembly process, independently of additional H-bond interactions.

16.
Org Lett ; 18(22): 5856-5859, 2016 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-27788006

RESUMO

The favorable spatial organization imposed by the square planar 4,4'-di(tert-butyl)-2,2'-bipyridine (dbbpy) platinum(II) complex associated with the electronic and shape complementarity of π-extended tetrathiafulvalene derivatives (exTTF) toward fullerenes is usefully exploited to construct molecular tweezers, which display good affinities for C60.

17.
J Am Chem Soc ; 138(29): 9025-8, 2016 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-27415660

RESUMO

An organogelator based on the Disperse Red nonlinear optical chromophore was synthesized according to a simple and efficient three-step procedure. The supramolecular gel organization leads to xerogels which display a spontaneous second harmonic generation (SHG) response without any need for preprocessing, and this SHG activity appears to be stable over several months. These findings, based on an intrinsic structural approach, are supported by favorable intermolecular supramolecular interactions, which promote a locally non-centrosymmetric NLO-active organization. This is in sharp contrast with most materials designed for SHG purposes, which generally require the use of expensive or heavy-to-handle external techniques for managing the dipoles' alignment.

18.
Chemistry ; 22(17): 5839-43, 2016 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-26864120

RESUMO

Straightforward modulation of the gelation, absorption and luminescent properties of a tris(pyrene) organogelator containing a C3 -symmetric benzene-1,3,5-tricarboxamide central unit functionalized by three 3,3'-diamino-2,2'-bipyridine fragments is achieved through donor-acceptor interactions in the presence of tetracyanoquinodimethane.

19.
Chem Asian J ; 11(1): 81-5, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26077967

RESUMO

A thorough study of the unexpected spectroscopic behavior of two new luminescent pyrene-urea-based organogelators is rationalized as a function of their aggregation state and provides a key method to probe the supramolecular organization of the material.


Assuntos
Géis/química , Substâncias Luminescentes/química , Pirenos/química , Géis/síntese química , Substâncias Luminescentes/síntese química , Substâncias Macromoleculares/síntese química , Substâncias Macromoleculares/química , Estrutura Molecular , Ureia/química
20.
Angew Chem Int Ed Engl ; 50(40): 9248-59, 2011 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-21901802

RESUMO

Custom-made macrocyclic receptors for fullerenes are proving a valuable alternative to achieve the affinity and selectivity required to meet challenges such as the selective extraction of higher fullerenes, their chiral resolution, or the self-assembly of functional molecular materials. In this Minireview, we highlight some of the important breakthroughs that this class of fullerene hosts has already produced.

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