1,721,289 research outputs found
MOLECULAR SENSING A universal receptor
No full textComplexes made of carbon nanotubes and polymers can potentially be used to selectively detect almost any molecule
Nano- and microstructuration of supramolecular materials driven by H-bonded uracil.2,6-diamidopyridine complexes
No full textIn the last few decades, multiple H-bonded arrays have been shown to be versatile tools to prepare functional supramolecular materials. Supramolecular complexes formed by uracil (Ur) and 2,6-diamidopyridine (DAP) developed by Lehn are the first examples of multiple H-bonded systems governing the formation of supramolecular polymers in solution. Although a large variety of complementary multiple H-bonded complexes has been prepared, the use of the heteromolecular Ur.DAP complex still remains very promising due to its ease of preparation and its intermediate association strength that ensures a dynamical character to the self-assembly and self-organisation processes. In this feature article, we report a detailed account on the results that our group has obtained in this field by designing and engineering a novel library of shape persistent molecular modules able to transfer their geometrical information to the final supramolecular architectures through the formation of Ur.DAP complexes both at the nanoscopic and microscopic levels
Filling carbon nanotubes for nanobiotechnological applications
No full textWith the great development in new filling methodologies for preparing endohedral carbon nanotubes, encapsulation strategies employing biomedically relevant molecular guests have emerged rapidly in recent years. All of these hybrid nanomaterials feature distinct properties and potential applications depending on both the chemical nature and spatial arrangement of the encapsulated molecular guests. In this focus article, we discuss the most significant examples in which carbon nanotube (CNTs) hybrids, filled with suitable molecular species, are used for biomedical applications. CNTs containing strongly emitting molecules hold great promises for diagnostic devices, whereas those filled with radioactive species and magnetically-active nanoparticles are attracting considerable attention for theranostic applications. Examples describing the use of the CNTs' tubular cavity as an active reservoir for the controlled release of drugs are also discussed. This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2014
Self-organization of polar porphyrinoids
No full textThis Minireview focuses on the very recent developments in the field of porphyrin-based self-assembled nanomaterials with a particular focus on the use of tetrapyrrolic macrocycles bearing amphiphilic and ionic functionalities. As one of the most studied molecular materials, the importance of porphyrin-derived nanomaterials has attracted wide interest in many applications like catalysis, photodynamic therapy, and organic solar cells to name a few. By using key examples that have recently appeared in the literature, the discussion unfolds through two sections: amphiphilic and ionic assemblies. Although it focuses on the nanostructuring methodologies used to obtain organized materials, the discussion will also target the physical characterization of the functional materials for their implementation in prototypes
Supramolecular Architectures of Porphyrins on Surfaces: the Structural Evolution from 1D to 2D to 3D to Devices
No full textTetrapyrrolic macrocycles, such as porphyrins, belong to a class of distinctively multifunctional biomolecules playing a central role in fundamental natural processes such as electron transfer, oxygen transfer, and light-harvesting, and their use to mimic these biological events in nanotechnological devices would be of obvious benefit Despite the synthetic and physical achievements, a technical impediment towards the exploitation of such porphyrin-based architectures in applicative devices is that they cannot be singularly addressed in solution or at solid state, as they must be interfaced with the external world They also need to show durability and functionality under the extreme conditions that are normally used in operating practical devices. Typically, porphyrin architectures have been investigated in solution, however, the tendency in current research is to deposit functional porphyrin derivatives on the surfaces of bulk materials such as metals or semiconductors and investigate the resultant hybrid surfaces using STM. In this review, we have illustrated the trends in supramolecular nanopatterning of porphyrin derivatives at different interfaces Various strategies for the construction of nanoscale architectures at different interfaces are described along the course of the review, including sublimation under UHV conditions. adlayer formation by immersion of a surface in a liquid or deposition of a solution The discussion of assemblies on surfaces commences with a description of the very recent developments in the remarkably precisely controlled construction of discrete assemblies on surfaces under UHV conditions. Subsequently, extended 2D arrays formed in both ambient conditions at the liquid-solid interface, as well as under UHV conditions have been discussed along with the ability of certain 2D self-assemblies to accommodate guest molecules. The last section of the review deals with porphyrin assemblies featuring three-dimensional properties, with a particular focus on those systems in which the third-dimension Introduces functionality such as gas-storage, catalysis and a molecular moto
Hierarchised Luminescent Organic Nanoarchitectures: Design, Synthesis, Self-assembly and Material Applications
No full textThis critical review aims at highlighting the prevailing supramolecular approaches employed nowadays in the preparation of luminescent hierarchised materials. Specifically, it has the ambition to illustrate how progresses in the control of the supramolecular interaction toolbox ultimately led to the development of spectacular luminescent nano- and micro-architectures, through a combination of molecular self-assembly and self-organisation processes involving organic π-conjugated molecules. The reader will be guided through a systematic exploration of the most common avenues to prepare and characterise luminescent self-assembled/self-organised materials embedded into one-, two- or three-dimensional networks, accompanied by a critical discussion of their main advantages and limitations. Key representative examples of this research field will be thoroughly described, with a particular focus on those systems displaying potential on the device application scene. Particular attention will be devoted to the design and synthetic approaches aimed at the preparation of the primary π-conjugated molecular modules, the chemical, structural and electronic properties of which dramatically influence the fate and the features of the self-assembled/self-organised material (215 references)
Photophysical Properties of Tolan Wavelength Shifters in Solution and Embedded in Polymeric Organic Thin Films
No full textLinear organic conjugated molecules, peripherally equipped with electron-donating and electron-accepting moieties, are recognized as one of the most promising classes of nonlinear optical materials for potential application in energy conversion devices, organic electronics, optical communication, information storage, and nuclear medicine techniques. In this work, we have synthesized and photophysically characterized a series of organic molecules constituted by a 1,2-diphenyl acetylene core (tolan) bearing electronically active groups directly linked to the pi-conjugated backbone. Tuning of the absorption and emission energies has been achieved via the push-pull effect. All investigated compounds displayed very high luminescence in condensed media from intramolecular charge transfer excited states with large Stokes shifts. These features revealed to be of particular interest for the engineering of new wavelength shifters for spectral conversion of deep ultraviolet to visible light
Organic reactivity in confined spaces under scanning tunneling microscopy control: Tailoring the nanoscale world
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Supramolecular [60]fullerene chemistry on surfaces
No full textThis critical review documents the exceptional range of research avenues in [60]fullerene-based monolayers showing unique and spectacular physicochemical properties which prompted such materials to have potential applications in several directions, ranging from sensors and photovoltaic cells to nanostructured devices for advanced electronic applications, that have been pursued during the past decade. It illustrates how progress in covalent [60]fullerene functionalisation led to the development of spectacular surface-immobilised architectures, including dyads and triads for photoinduced electron and energy transfer, self-assembled on a wide variety of surfaces. All of these molecular assemblies and supramolecular arrays feature distinct properties as a consequence of the presence of different molecular units and their spatial arrangement. Since the properties of [60]fullerene-containing films are profoundly controlled by the deposition conditions, substrate of adsorption, and influenced by impurities or disordered surface structures, the progress of such new [60]fullerene-based materials strongly relies on the development of new versatile and broad preparative methodologies. Therefore, the systematic exploration of the most common approaches to prepare and characterise [60]fullerene-containing monolayers embedded into two- or three-dimensional networks will be reviewed in great detail together with their main limitations. Recent investigations hinting at potential technological applications addressing many important fundamental issues, such as a better understanding of interfacial electron transfer, ion transport in thin films, photovoltaic devices and the dynamics associated with monolayer self-assembly, are also highlighted
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