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Nikitin A.G.,CNRS Interdisciplinary Center on Nanoscience in Marseille
Applied Physics Letters | Year: 2015

This Letter reports theoretical and experimental study of transverse-magnetic-like lattice plasmon modes originating from diffraction in periodic two dimensional arrays of metal nanoparticles. These modes lead to the transmission and reflection spectra exhibiting narrow linewidth Fano-like resonances which can appear as maxima, minima, or can have asymmetric peak-and-dip profile. The dependencies of the position and lineshape of the resonance on the lattice periodicity and angle of incidence are investigated. Numerical simulations of electric field distributions for different excitation conditions of lattice plasmon modes are also performed. © 2014 AIP Publishing LLC.

Thibaudau F.,Aix - Marseille University | Thibaudau F.,CNRS Interdisciplinary Center on Nanoscience in Marseille
Journal of Physical Chemistry Letters | Year: 2012

We report results on ultrafast photothermal release of DNA from gold nanoparticles. We show that dehybridization of oligonucleotide duplex anchored on a gold nanoparticle surface occurs during a single laser pulse, leading to the release of single-strand DNA in solution. Breaking of the Au-S bond anchoring the duplex and the release of thiolated DNA are also evidenced. Our findings show that the size distribution of the nanoparticles plays a major role in the control of both phenomena. We establish a criterion regarding the size distribution of nanoparticles that allows full release of DNA without breaking of the anchoring thiol bonds. © 2012 American Chemical Society.

Gingras M.,CNRS Interdisciplinary Center on Nanoscience in Marseille | Gingras M.,Aix - Marseille University
Chemical Society Reviews | Year: 2013

Carbohelicenes are a class of fascinating chiral helical molecules which have a rich history in chemistry. Over a period of almost 100 years, chemists have developed many methods to prepare them in a racemic or in a non-racemic form. They also possess a series of interesting chiral, physical, electronic and optical properties. However, their utilization in chemistry or chemistry-related fields has rarely appeared in a detailed and comprehensive review. It is the purpose of this review to collect fundamental applications and functions involving carbohelicenes in various disciplines such as in materials science, in nanoscience, in biological chemistry and in supramolecular chemistry. From the numerous synthetic methodologies reported up to now, carbohelicenes and their derivatives can be tailor-made for a better involvement in several subfields. Among those domains are: nanosciences, chemosensing, liquid crystals, molecular switches, polymers, foldamers, supramolecular materials, molecular recognition, conductive and opto-electronic materials, nonlinear optics, chirality studies and asymmetric synthesis. Helicene chemistry is now at a developmental stage, where sufficient application data are now collected and are extremely useful. They provide many more ideas for setting up the basis for future innovative applications. © 2013 The Royal Society of Chemistry.

Paramonov S.V.,RAS Nesmeyanov Institute of Organoelement Compounds | Lokshin V.,CNRS Interdisciplinary Center on Nanoscience in Marseille | Fedorova O.A.,RAS Nesmeyanov Institute of Organoelement Compounds
Journal of Photochemistry and Photobiology C: Photochemistry Reviews | Year: 2011

The review describes photoswitchable molecular receptors based on spiropyran, spirooxazine, and chromene molecules. The presence of coordination centers in their structures defines the ability of such compounds to coordinate metal ions, amino acids and DNA molecules, the process being accompanied by changes in optical characteristics. Major reports describing the complex formation of spiropyrans are devoted to complexation of metal ions. Except simple substituted spiropyrans, the crown and calixarene containing spiropyrans as well as polymer composition with spiropyrans possess the effective photoswitching receptor properties. The metal complexes of spiropyrans demonstrate the photocontrolled charge and energy transfer properties. Several examples of the photochromic systems sensitive to a number of biological objects such as amino acids, proteins and DNA are described. A number of papers are devoted to the complex formation involving of spirooxazine molecules with metal ions, cyclodextrins and amino acids. The studies of benzo- and naphthopyran ligands involved mainly the incorporation of crown ether fragments into naphthopyran molecules. Very few articles describe alternative coordination functions. © 2011 Elsevier B.V.

Gingras M.,CNRS Interdisciplinary Center on Nanoscience in Marseille | Gingras M.,Aix - Marseille University
Chemical Society Reviews | Year: 2013

Carbohelicenes belong to a class of fascinating, chiral, and helicoidal molecules, which have a rich history in chemistry since the very beginning of the 20th century. A renewed interest in polyaromatic chemistry and new synthetic challenges toward the search for innovative physical, biological, chemical and opto-electronic properties have brought high motivation in this field of studies. Theoretical insights gained from polyaromatic, chiral, conjugated and distorted π-systems are also responsible for this development. Several synthetic avenues were originally reported for making lower helicenes, but for many years, photochemical synthesis has remained a major method for producing small amount of helicenes. High-dilution conditions is still a limiting factor in their synthesis. The fulgurous impact of organometallic chemistry, novel synthetic methods, and recent catalytic systems has promoted the development of helicene chemistry, toward a library of tailor-made and highly functionalized helicene molecules. Helicene chemistry is being considered as an expanding and modern field, leading to several applications in supramolecular chemistry, in nanosciences, in chemical-biology, in polymers and materials science. This first part of a series of three reviews on carbohelicenes will be devoted to a comprehensive report on non-stereoselective reactions and methods for producing helicenes, along with their functionalization. © 2013 The Royal Society of Chemistry.

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