Searching for New Borondifluoride Beta-diketonate Complexes with Enhanced Absorption-Emission Properties using ab initio Tools

International audienc

Tiara-like Complexes acting as Iodine Encapsulating Agents: The Role of M···I Interactions in [M(μ-SCH2CO2Me)2]8⊂I2 (M = Ni, Pd, Pt) Inclusion Compounds.

International audienc

Tiara-like Complexes acting as Iodine Encapsulating Agents: The Role of M⋯I Interactions in [M(μ-SCH2CO2Me)2]8⊂I2 (M = Ni, Pd, Pt) Inclusion Compounds

International audienceA proposed series of tiara-like complexes [M(μ-SCH2CO2Me)2]8 (where M = Ni, Pd, Pt) are here studied through DFT methodologies prompted by the synthesis of the palladium parent and their potential application in iodine encapsulation from spent nuclear fuel. Their hollow structure with a suitable cavity size, and the presence of several transition-metal centers capable to directly interact with an I2 molecule through noncovalent forces, make them attractive inclusion agents. Herein, an energy decomposition analysis reveals that forces responsible for keeping the guest molecule in the inner cavity are mainly electrostatic; a remarkable feature given, in principle, the neutral nature of both the host and guest species, offering us an interesting study case where the electronic cloud distortion of the binding sites and iodine atoms can be estimated and related to the intensity of the host-guest interactions. Our results shed light into the application of the nickel tiara-like host as an alternative to the reported [Pd(μ-SCH2CO2Me)2]8 system. This research can be useful for further evaluation of nickel-based iodine sequestering agents prior to engaging in explorative synthesis efforts

Combined TD-DFT-SOS-CIS(D) Study of BOPHY Derivatives with Potential Application in Biosensing

International audienceA set of 13 bis(difluoroboron)-1,2-bis((pyrrol-2-yl)methylene)hydrazine (BOPHY) dyes is studied through a hybrid time-dependent density functional theory (TD-DFT)-scaled opposite spin-configuration interaction singles with a double correction [SOS-CIS(D)] approach accounting for solvent effects, to shed light onto the structure-property relationships of these recently developed chromophores. In the first step, we calculate the absorption-fluorescence crossing points with refined TD-DFT models considering the influences of both vibrational and solvent contributions. We found that the systematic overestimation of the 0-0 energies is effectively reduced by combining polarizable continuum model-TD-DFT with a scaled opposite spin-configuration interaction singles with a double correction [SOS-CIS(D)]. Next, for a representative system, the vibrationally resolved spectrum within the harmonic approximation is computed on the basis of TD-DFT vibrational signatures and an excellent match with experiment is found. Finally, the influence of different lateral groups on the spectroscopic properties is rationalized by investigating charge transfer parameters and examining electronic density difference maps. It is found that one can tune the position of the absorption/emission maxima by a judicious choice of the lateral substituents or by using pi-extended segments. The largest absorption and emission wavelengths as well as the largest Stokes shifts are obtained for BOPHYs containing strong electron-donor dimethylaminophenyl groups attached to the alpha-positions of the pyrrole units through vinyl linkers, making these chromophores promising candidates for bioluminescence applications

Rationalisation of the Optical Signatures of nor-Dihydroxanthene-Hemicyanine Fused Near-Infrared Fluorophores By First Principle Tools

International audienc

Ethynylene-analogues of hemicurcuminoids: Synthesis and ground- and excited properties of their boron difluoride complexes

International audienc

Borondifluoride complexes of hemicurcuminoids as bio-inspired push–pull dyes for bioimaging

International audienceHemicurcuminoids are based on half of the π-conjugated backbone of curcuminoids. The synthesis of a series of such systems and their borondifluoride complexes is described. The electrochemical and photophysical properties of difluorodioxaborine species were investigated as a function of the nature of electron donor and acceptor groups appended at either terminal positions of the molecular backbone. The emissive character of these dipolar dyes was attributed to an intraligand charge transfer process, leading to fluorescence emission that is strongly dependent on solvent polarity. Quasi-quantitative quenching of fluorescence in high polarity solvents was attributed to photoinduced electron transfer. These dyes were shown to behave as versatile fluorophores. Indeed, they display efficient two-photon excited fluorescence emission leading to high two-photon brightness values. Furthermore, they form nanoparticles in water whose fluorescence emission quantum yield is less than that of the dye in solution, owing to aggregation-induced fluorescence quenching. When cos7 living cells were exposed to these weakly-emitting nanoparticles, one- and two-photon excited fluorescence spectra showed a strong emission within the cytoplasm that originated from the individual molecules. Dye uptake thus involved a disaggregation mechanism at the cell membrane which restored fluorescence emission. This off–on fluorescence switching allows a selective optical monitoring of those molecules that do enter the cell, which offers improved sensitivity and selectivity of detection for bioimaging purposes

3er. Coloquio: Fortalecimiento de los Colectivos de Docencia

Las memorias del 3er. Coloquio de Fortalecimiento de Colectivos de Docencia deben ser entendidas como un esfuerzo colectivo de la comunidad de académicos de la División de Ciencias y Artes para el Diseño, en medio de la pandemia COVID-19, con el fin de: • Analizar y proponer acciones concretas que promuevan el mejoramiento de la calidad docente en la División. • Proponer acciones que permitan continuar fortaleciendo los cursos con modalidad a distancia (remotos). • Ante un escenario que probablemente demandará en el mediano plazo, transitar del modelo remoto a un modelo híbrido, proponer acciones a considerar para la transición de los cursos. • Planear y preparar cursos de nivelación de conocimientos, para cuando se transite a la impartición de la docencia de manera mixta o presencial, dirigidos a los alumnos que no hayan tenido oportunidad de desarrollar actividades relevantes para su formación, como prácticas de talleres y laboratorios, visitas, o alguna otra actividad relevante

Compilación de Proyectos de Investigacion de 1984-2002

Instituto Politecnico Nacional. UPIICS