Search results for "Cyanine"

Light-Emitting Electrochemical Cells Using Cyanine Dyes as the Active Components

2013

Light-emitting electrochemical cells (LECs) based on cyanine molecules were prepared. High photoluminescence quantum yields were obtained for host-guest films using two cyanine dyes, reaching 27%. Sandwiching these films in between two electrodes allows for very stable near-infrared emission with a maximum radiant flux of 1.7 W m(-2) at an external quantum efficiency of 0.44%.

Concentration depending fluorescence of 8-(di-(2-picolyl)) aminoBODIPY in solution

2014

[EN] An 8-dipicolylBODIPY derivative has been prepared and its photophysical properties evaluated under different conditions. Two different structures, hemicyanine and cyanine, are observed (depending on the solvent or the solution concentration). The hemicyanine form is not emissive whereas the cyanine form is fluorescent. This behavior is related with the planarity degree of the BODIPY core. The X-ray structure of the compound is reported and it shows that in solid state the hemicyanine form is present. The hemicyanine form seems to be stabilized by aggregation and is the main compound in concentrated solutions whereas the cyanine form is present in diluted solutions that are photochemica…

Phthalocyanines-TiO2: A New Efficient and Tunable Catalyst for CO2 Reduction in Water

2014

Semiconductor @ sensitizer composites for enhanced photoinduced processes

2021

This Chapter provides an overview of common procedures used for the preparation, characterization, and exploration of photocatalytic properties of composite materials based on inorganic semiconductors in combination with sensitizers, such as porphyrins, phthalocyanines, and related macrocyclic compounds as promoters of photoinduced processes. In this context the advantage of hybrid photocatalysts, obtained by impregnation of photosensitizers onto the surface of different semiconductors, designed for improving a choice of diverse reactions has been demonstrated, highlighting innovative aspects that contribute to better sustainability of the photocatalytic processes. Mechanistic details conce…

Oligodendrocytes in mouse corpus callosum are coupled via gap junction channels formed by connexin47 and connexin32.

2010

According to previously published ultrastructural studies, oligodendrocytes in white matter exhibit gap junctions with astrocytes, but not among each other, while in vitro oligodendrocytes form functional gap junctions. We have studied functional coupling among oligodendrocytes in acute slices of postnatal mouse corpus callosum. By whole-cell patch clamp we dialyzed oligodendrocytes with biocytin, a gap junction-permeable tracer. On average 61 cells were positive for biocytin detected by labeling with streptavidin-Cy3. About 77% of the coupled cells stained positively for the oligodendrocyte marker protein CNPase, 9% for the astrocyte marker GFAP and 14% were negative for both CNPase and GF…

J-aggregates prepared by adsorption at monolayer/water interfaces

1991

By adsorption of anionic cyanine dyes at positivly charged lipid monolayers large J-aggregates are formed. Absorption and fluorescence spectra are measured at the air/water interface during the crystallization process. The influence of the lipid/dye interaction on the aggregate structure is studied for two different systems. It is shown that the aggregate structure can be improved by growing crystals from a seed.

Concentration dependence of the electro-optical spectra from two-dimensional aggregated chromophore systems

1991

The linear and the quadratic Stark effects have been employed to characterize aggregate formation of an amphiphilic cyanine dye mixed with arachidic acid in various concentrations within Langmuir-Blodgett multilayers. Two different electrode configurations with the electric field directions parallel and normal to the films have been employed to test the responses of the electronic spectra to external fields. The observations have been used to quantify the induced and static dipole moment changes on excitation of the chromophores. A comparison of the results obtained from different multilayer arrangements is suggestive of inter-layer couplings for the case of head-to-head configurations of t…

Molecular Engineering of Porphyrin‐Tapes/Phthalocyanine Heterojunctions for a Highly Sensitive Ammonia Sensor

2020

International audience; Modulating the interfacial charge alignments by molecular engineering in an organic heterojunction device is a smart strategy to improve its conductivity, which can be exploited in high performance gas sensors development. Herein, the fabrication of new organic heterojunction devices based on porphyrin tapes and phthalocyanines and their potentiality in ammonia sensing at different relative humidity (rh) are investigated. The devices are built using dry approach relying on oxidative chemical vapor deposition for simultaneous synthesis, doping and deposition of the porphyrin tape layer and physical vapor deposition of phthalocyanine layer. The association of the porph…

Synthèse in situ de fluorophores organiques : formation de liaisons covalentes par déclenchement enzymatique et applications en biodétection

2017

Fluorescence imaging is a growing field of biology over the past decades. Intensive works mainly focused on instrumental developments and chemistry of contrast agents (probes), were already done to improve such bioanalytical technique. The main goal of this Ph. D. thesis was to explore various fluorogenic molecular platforms responsive to various (bio)chemical stimuli and capable of releasing organic fluorophores in the biological medium to analyze. This approach named "in-situsynthesis" is based on domino reactions belonging to the repertoire of "covalent chemistry", triggered by the target (bio)analyte. This kind of process should provide advanced fluorogenic probes with high signal-to-no…

Development of functionalized SYBR green II related cyanine dyes for viral RNA detection

2020

Abstract Fluorescent probes for sensing nucleic acids have found widespread use in the field of cell and molecular biology. However, probes combined with potential for post-synthetic conjugation, e.g. for intra-endosomal measurements of RNA, are unavailable. Herein we developed cyanine dyes that can be conjugated to viral capsid or other targets. First, we solved the crystal structure of SYBR Green II. The structural elucidation of this commonly used RNA probe provided the basis for synthesizing similar molecules with much desired function for post-synthetic conjugation. To address this need, cyanine dyes were prepared using an alternative synthesis protocol. All studied compounds showed co…