Person:
Cabrera González, Justo Enrique

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First Name
Justo Enrique
Last Name
Cabrera González
URI
https://hdl.handle.net/20.500.14352/84486
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Orgánica
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2016 - 20172
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End date: 2023 × Subject: 615:54 ×

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    Tetrakis{[(p-dodecacarboranyl)methyl]stilbenyl}ethylene:A Luminescent Tetraphenylethylene (TPE) Core System
    (European Journal of Inorganic Chemistry, 2017) Cabrera González, Justo Enrique
    The synthesis and spectroscopic characterization of the first set of tetrakis{[(p-dodecacarboranyl)methyl]stilbenyl}ethylenes (TDSE), substituted either with a methyl or a phenyl group in the 2-position (Ccluster) of the ortho-carborane, are described. The complex absorption properties are elucidated by TD-DFT calculations, stressing the importance of through-bond conjugation. Enhanced conjugation and restriction of the conformational space are identified as the main factors for boosted luminescence properties in solution, compared with the tetraphenylethylene (TPE) core, effectively reducing internal conversion (IC). IC is further reduced when aggregate suspensions of our compounds are formed in water, providing highly luminescent materials of quasi-isolated (very weakly interacting) emitters.
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    Photoluminescence in Carborane–Stilbene Triads: A Structural, Spectroscopic, and Computational Study
    (Chemistry - a European journal, 2016) Cabrera González, Justo Enrique; Viñas, Clara; Haukka, Matti; Bhattacharyya, Santanu; Gierschner, Johannes; Núñez, Rosario
    A set of triads in which o- and m-carborane clusters are bonded to two stilbene units through Ccluster−CH2 bonds was synthesized, and their structures were confirmed by X-ray diffraction. A study on the influence of the o- and m- isomers on the absorption and photoluminescence properties of the stilbene units in solution revealed no charge-transfer contributions in the lowest excited state, as confirmed by (TD)DFT calculations. The presence of one or two B−I groups in m-carborane derivatives does not affect the emission properties of the stilbenes in solution, probably due to the rather large distance between the iodo substituents and the fluorophore. Nevertheless, a significant redshift of the photoluminescence (PL) emission maximum in the solid state (thin films and powder samples) compared to solution was observed; this can be traced back to PL sensitization, most probably due to more densely packed stilbene moieties. Remarkably, the PL absolute quantum yields of powder samples are significantly higher than those in solution, and this was attributed to the restricted environment and the aforementioned sensitization. Thus, the bonding of the carborane clusters to two stilbene units preserves their PL behavior in solution, but produces significant changes in the solid state. Furthermore, iodinated species can be considered to be promising precursors for theranostic agents in which both imaging and therapeutic functions could possibly be combined.