Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Chem Commun (Camb) ; 2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-32104794

RESUMO

Two 1,1,4,4-tetracyanobutadiene (TCBD) derivatives were prepared by [2+2]cycloaddition-retroelectrocyclization from ynamides bearing either a pyrene (1) or a perylene unit (2). In addition to panchromatic absorptions in 2, in the solid state, both compounds unexpectedly display NIR photoluminescence that could be detected up to about 1350 nm.

3.
Inorg Chem ; 57(4): 2296-2307, 2018 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-29393633

RESUMO

A computationally inspired Cu(I) metal-to-ligand charge transfer (MLCT) chromophore, [Cu(sbmpep)2]+ (sbmpep = 2,9-di(sec-butyl)-3,8-dimethyl-4,7-di(phenylethynyl)-1,10-phenanthroline), was synthesized in seven total steps, prepared from either dichloro- or dibromophenanthroline precursors. Complete synthesis, structural characterization, and electrochemistry, in addition to static and dynamic photophysical properties of [Cu(sbmpep)2]+, are reported on all relevant time scales. UV-Vis absorption spectroscopy revealed significant increases in oscillator strength along with a concomitant bathochromic shift in the MLCT absorption bands with respect to structurally related model complexes (ε = 16 500 M-1 cm-1 at 491 nm). Strong red photoluminescence (Φ = 2.7%, λmax = 687 nm) was observed from [Cu(sbmpep)2]+, which featured an average excited-state lifetime of 1.4 µs in deaerated dichloromethane. Cyclic and differential pulse voltammetry revealed ∼300 mV positive shifts in the measured one-electron reversible reduction and oxidation waves in relation to a Cu(I) model complex possessing identical structural elements without the π-conjugated 4,7-substituents. The excited-state redox potential of [Cu(sbmpep)2]+ was estimated to be -1.36 V, a notably powerful reductant for driving photoredox chemistry. The combination of conventional and ultrafast transient  absorption and luminescence spectroscopy successfully map the excited-state dynamics of [Cu(sbmpep)2]+ from initial photoexcitation to the formation of the lowest-energy MLCT excited state and ultimately its relaxation to the ground state. This newly conceived molecule appears poised for photosensitization reactions involving energy and electron-transfer processes relevant to photochemical upconversion, photoredox catalysis, and solar fuels photochemistry.

4.
Chemistry ; 24(14): 3408-3412, 2018 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-29341302

RESUMO

The design of original twisted charge transfer antennae in which a non-planar geometry is enforced thanks to one or two bulky ortho-Me substituents allows us to prepare the corresponding ultra-bright TbIII and DyIII bioprobes. The brightness of the TbIII derivative compares well with that of the benchmark Tb-Lumi4 complex. The first bio-imaging experiments with a DyIII luminescent bioprobe are also reported.

5.
Chem Commun (Camb) ; 53(44): 6005-6008, 2017 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-28516180

RESUMO

An Yb(iii) complex based on a dimethyl cyclen macrocyclic ligand functionalized by charge transfer antennae was prepared. This cationic [YbL3]+ complex is stable and soluble in water and presents interesting photophysical nonlinear properties. It is spontaneously internalized and accumulates in live cells. High quality images have been obtained both in a classical NIR-to-vis configuration and in the more challenging NIR-to-NIR one.


Assuntos
Complexos de Coordenação/química , Corantes Fluorescentes/química , Imagem Óptica , Fótons , Itérbio/química , Cátions/química , Linhagem Celular Tumoral , Sobrevivência Celular , Humanos , Raios Infravermelhos , Conformação Molecular
6.
J Am Chem Soc ; 139(23): 7693-7696, 2017 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-28551987

RESUMO

Fluorescent probes that are able to directly measure viscosity are attractive candidates for the study of intracellular environments. We report a new class of luminescent rotors, based on the sensitized emission of a terbium(III) complex. A 4-fold increase in both quantum yield and luminescence lifetime was observed in viscous media for the studied complexes, with a lifetime ranging from 0.23 to 0.89 ms over a broad range of viscosities (0.6-1200 cP). The presented approach, relying on the millisecond-scale luminescence lifetime of the lanthanide ions, was applied to fixed T24 cancer cells using temporal sampling lifetime imaging microscopy.

7.
Inorg Chem ; 55(14): 7020-5, 2016 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-27367598

RESUMO

An original cationic water-soluble cyclen-based Eu(III) complex [EuL(1)](+) featuring a chromophore-functionalized antenna to increase the two-photon (2P) absorption properties was synthesized. The photophysical properties were thoroughly studied in various solvents and rationalized with the help of theoretical calculations. The complex exhibits an optimized 2P absorption cross section. Finally, 2P microscopy imaging experiments on living T24 human cancer cells highlighted the spontaneous internalization and the biological stability of this 2P bioprobe in vitro. Macrocyclic-based antennas open new perspectives for future optimization of the photophysical properties and allows envisaging the design of Eu, Tb, Yb, and Sm bioprobes. This result also opens the way for the design of functional two-photon Ln complexes able to monitor intracellular physicochemical parameters.


Assuntos
Elementos da Série dos Lantanídeos/metabolismo , Sondas Moleculares/metabolismo , Cátions , Microscopia/métodos
8.
Chemistry ; 21(49): 17757-61, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26489885

RESUMO

An original samarium(III) complex based on a triazacyclononane platform functionalized with a charge-transfer antenna chromophore exhibited optimized brightness and was successfully used as an emissive species for two-photon microscopy experiments in both the visible and near-infrared spectral ranges.

9.
Dalton Trans ; 44(11): 4918-24, 2015 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-25421299

RESUMO

During the course of our research studies aiming to combine the unique photophysical properties of lanthanide complexes and the intrinsic advantage of a nonlinear two-photon excitation, we described the proof-of-concept of a biphotonic multiplexing bio-imaging experiment. To that end, a new Tb-luminescent bioprobe [TbL(2)] was designed using the TACN-trispicolinate platform. The biphotonic imaging of T24 fixed cells stained either with [TbL(2)] or with the already described [EuL(1)] complexes is reported. Finally the biphotonic multiplexing experiment was performed using a combination of both probes using the spectral mode of the two-photon microscope.


Assuntos
Európio/química , Imagem Molecular/métodos , Fótons , Térbio/química , Linhagem Celular Tumoral , Humanos , Substâncias Luminescentes/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA