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The photodynamics of an orthogonal BODIPY dimer, particularly the formation of triplet states, has been explored by femtosecond and nanosecond transient absorption measurements. The short time scale data show the appearance of transient features of triplet character that, according to quantitative analysis of their intensities, account for more than 100% of the initially excited molecules, which reveals the occurrence of a singlet fission process in the isolated dimers. The formation rate of the triplet correlated state 1(TT) is found to depend on the solvent polarity, pointing to the mediation of a charge transfer character state. The dissociation of the 1(TT) state into pairs of individual triplets determines the triplet yield measured in the long time scales. The kinetic model derived from the results provides a comprehensive view of the photodynamics of BODIPY dimers and permits rationalization of the photophysical parameters of these systems., Ministerio de Economía y Competitividad (MINECO), Gobierno Vasco, Sección Deptal. de Química Orgánica (Óptica y Optometría), Fac. de Óptica y Optometría, TRUE, pub

Received 30 January 2017, Revised 10 March 2017, Accepted 11 March 2017, Available online 12 March 2017., Despite fluorescent photodynamic therapy (fluorescent-PDT) dyes are promising theranostic agents, current approaches unfortunately involve crucial shortcomings (such as, narrow absorption bands, high cost, low bio-compatibility and specificity, low dual efficiency) making difficult their clinical translation. Particularly, efficient fluorescent-PDT agents triggered under white-light, with potential application in topic solar treatments, are scarce. Here, we describe the rational development of a novel fluorescent-PDT molecular biomaterial based on BODIPY building blocks able to sustain, simultaneously, synthetic accessibility, high fluorescence and phototoxicity within a broad spectral window, biocompatibility, including low dark toxicity and high cell permeability with selective accumulation in lysosomes and, what is more important, excellent efficient activity triggered under white light. These all-in-one combined properties make the new dye a valuable ground platform for the development of future smarter theranostic agents., Ministerio de Economía y Competitividad (MINECO), Comunidad de Madrid, Gobierno Vasco, Sección Deptal. de Química Orgánica (Óptica y Optometría), Fac. de Óptica y Optometría, TRUE, pub

Manuscript Received: 14 DEC 2016; Accepted manuscript online: 6 FEB 2017; Version of Record online: 21 MAR 2017; Issue online: 10 APR 2017, The synthesis, photophysical characterization, and modeling of a new library of halogen-free photosensitizers (PS) based on orthogonal boron dipyrromethene (BODIPY) dimers are reported. Herein we establish key structural factors in order to enhance singlet oxygen generation by judiciously choosing the substitution patterns according to key electronic effects and synthetic accessibility factors. The photosensitization mechanism of orthogonal BODIPY dimers is demonstrated to be strongly related to their intrinsic intramolecular charge transfer (ICT) character through the spin-orbit charge-transfer intersystem crossing (SOCT-ISC) mechanism. Thus, singlet oxygen generation can be effectively modulated through the solvent polarity and the presence of electron-donating or withdrawing groups in one of the BODIPY units. The photodynamic therapy (PDT) activity is demonstrated by in vitro experiments, showing that selected photosensitizers are efficiently internalized into HeLa cells, exhibiting low dark toxicity and high phototoxicity, even at low PS concentration (0.05–5×10−6 m)., Ministerio de Ciencia e Innovación (MICINN), Ministerio de Economía y Competitividad (MINECO), Comunidad de Madrid, Gobierno Vasco, Sección Deptal. de Química Orgánica (Óptica y Optometría), Fac. de Óptica y Optometría, TRUE, pub

198 p., Along this manuscript different hybrid materials are synthesized and extensively characterized for several used: from optical to therapeutic applications. First, by the incorporation of different dyes, styryl 722 and pyronine into several smectite clay films, macroscopically ordered systems are obtained. The effect of the clay on the dye is deeply analysed and its preferential orientation is studies by anisotropic response of the films to the linear polarized light. Second, large monoliths with embedded laser dyes with strong absorption and fluorescence bands in different region of the visible spectrum are attained by sol gel chemistry to obtain solid-state dye laser (SSDL) with good photo, thermal and chemical stabilities. Third, silica NP (NP) with suitable size (50 nm) and functionalized external surface are also synthesized by sol gel chemistry. Through the encapsulation of fluorescent dye molecules in their core and by the grafting of the photosensitizers on their shell, biocompatible nanoparticles for bio-imaging and photodynamic therapy (PDT) applications are prepared. In order to optimize their properties, a careful investigation of the photophysical properties and mainly the singlet oxygen generation of a large range of new photosensitizer based on chromophores known as BODIPYs, is previously carried out. Based on the results, some efficient BODIPYs are selected for grafting on silica nanoparticles in order to use them for PDT.