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This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Catalysis, copyright ©2018 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/abs/10.1021/acscatal.8b01331 ; A bifunctional photoaminocatalyst based on imidazolidinone and thioxanthone is presented. The preparation of these catalysts proceeds in a two-step synthesis that allows an easy tuning of the steric properties. The photophysical and electrochemical data of the imidazolidinone photocatalysts have been determined, indicating that the catalysts can work under visible light conditions. To corroborate the experimental observations, ground state geometry optimization and energy transition studies of thioxanthone and bifunctional catalyst 4c were optimized by time-dependent density functional theory (TD DFT) calculations. The alkylation of aldehydes with this photoaminocatalyst works with high enantioselectivities and yields due to the stereoelectronic properties of the catalyst. A rational mechanistic cycle based on different mechanistic experiments, TD DFT calculations, and laser flash photolysis is presented ; The Spanish Government (CTQ2015-64561-R) and the European Research Council (ERC-CG, Contract 647550) are acknowledged

Developing highly efficient photocatalysts for artificial photosynthesis is one of the grand challenges in solar energy conversion. Among advanced photoactive materials, conjugated porous polymers (CPPs) possess a powerful combination of high surface areas, intrinsic porosity, cross-linked nature, and fully π-conjugated electronic systems. Here, based on these fascinating properties, organic–inorganic hybrid heterostructures composed of CPPs and TiO2 for the photocatalytic CO2 reduction and H2 evolution from water are developed. The study is focused on CPPs based on the boron dipyrromethene (BODIPY) and boron pyrrol hydrazine (BOPHY) families of compounds. It is shown that hybrid photocatalysts are active for the conversion of CO2 mainly into CH4 and CO, with CH4 production 4 times over the benchmark TiO2. Hydrogen evolution from water surpassed by 37.9-times that of TiO2, reaching 200 mmol gcat−1 and photonic efficiency of 20.4% in the presence of Pt co-catalyst (1 wt% Pt). Advanced photophysical studies, based on time-resolved photoluminescence and transient absorption spectroscopy, reveal the creation of a type II heterojunction in the hybrids. The unique interfacial interaction between CPPs and TiO2 results in longer carriers' lifetimes and a higher driving force for electron transfer, opening the door to a new generation of photocatalysts for artificial photosynthesis. ; This work received funding from the European Union's Horizon 2020 research and innovation program under European Research Council (ERC) through the HyMAP project (grant agreement No. 648319) as well as the Marie Skłodowska-Curie grant agreement No 754382. Financial support was received from AEI-MICINN/FEDER, UE through the Nympha Project (PID2019-106315RB-I00), the regional government of "Comunidad de Madrid" and the European Structural Funds through their financial support to FotoArt-CM project (S2018/NMT-4367). Besides, Fundación Ramon Areces funded this work through the ArtLeaf project. L.C. acknowledges the European Union's Horizon 2020 ...

[EN] Truxene-based porous polymers synthesized through the simple "solvent knitting" strategy from hexamethyl or tribenzyl truxene-based monomers (TxPP1 and TxPP2), and their corresponding TxPP@TiO2 hybrids are used as photocatalysts for H2 production from water using methanol as sacrificial agent, under UV-Vis light. These polymers present higher hydrogen evolution rate (HER) than TiO2, and remarkable thermo- and photo-stabilities. Hybrids TxPP-TiO2 exhibited intensely enhanced photocatalytic activity compared to TiO2 or TxPPs alone. In the presence of platinum (1%) as cocatalyst, HER from TxPP1@T-10 significantly boosted reaching values above 21000 μmol.g-1.h-1 which to the best of our knowledge, represents the highest HER reported for hybrids based on TiO2 and conjugated porous polymers. Interestingly, small structural differences of the corresponding truxene monomers result in different photocatalytic behavior. We focused here on gaining insight on the charge transfer mechanism and rationalizing the different photocatalytic performances in order to establish clear structure-activity relationships. In fact, photoluminescence and transient absorption spectroscopy demonstrated that the remarkably enhanced photocatalytic activity of the most active hybrids (TxPP1@TiO2) can be attributed to the efficiently photogenerated electron-hole separation by a direct Z-scheme mechanism, while lower performance of TxPP2@TiO2, is probably due to a less efficient heterojunction type II charge transfer mechanism. ; Authors acknowledge to MINECO/AEI/FEDER, UE of Spain (Projects MAT2017-82288-C2-2-P, CTQ2016-78557-R and ENE2016-79608-C2-1-R) and regional government of "Comunidad de Madrid" and European Structural Funds for their financial support to FotoArt-CM project (S2018/NMT-4367). AVG thanks Ministerio de Educación y Formación Profesional for FPU17/03463, M. L and M. B thank to MINECO and European Social Fund for a Ramón y Cajal grant (RyC-2015-18677) and Juan de la Cierva Formación grant (FJCI-2016-30567) respectively. ; Peer reviewed

The most useful strategies for the alkylation of allylic systems are related to the Tsuji–Trost reaction or the use of different Lewis acids. Herein we report a photocatalytic approach for the allylation reaction of a variety of nucleophiles, such as heteroarenes, amines and alcohols. This method is compatible with a large variety of pyrroles and indoles, containing different substituents such as electron-withdrawing and electron-donating groups, unprotected nitrogen atoms and bromo derivatives. Moreover, this methodology enables the chromoselective synthesis of Z- or E-allylated compounds. While the use of UV-light irradiation has allowed the synthesis of the previously inaccessible Z-allylated products, E-isomers are prepared simply by changing both the light source to the visible region, and the catalytic system. Based on mechanistic and photochemical proofs, laser flash photolysis studies and DFT calculations, a rational mechanism is presented ; Financial support from the Spanish Government (CTQ2015-64561-R), CCC-UAM (computing time), and ERC (ERC-CG, 647550, 648319) is acknowledged. L.M., R.P-R, and R.C. thank CAM for the "Atracción de Talento" fellowship. The authors thank "Comunidad de Madrid" and European Structural Funds for their financial support to FotoArt-CM project (S2018/NMT-4367). We thank Miguel Ángel Miranda for helpful discussions about photochemical mechanisms

The most useful strategies for the alkylation of allylic systems are related to the Tsuji–Trost reaction or the use of different Lewis acids. Herein we report a photocatalytic approach for the allylation reaction of a variety of nucleophiles, such as heteroarenes, amines and alcohols. This method is compatible with a large variety of pyrroles and indoles, containing different substituents such as electron-withdrawing and electron-donating groups, unprotected nitrogen atoms and bromo derivatives. Moreover, this methodology enables the chromoselective synthesis of Z- or E-allylated compounds. While the use of UV-light irradiation has allowed the synthesis of the previously inaccessible Z-allylated products, E-isomers are prepared simply by changing both the light source to the visible region, and the catalytic system. Based on mechanistic and photochemical proofs, laser flash photolysis studies and DFT calculations, a rational mechanism is presented. ; Financial support from the Spanish Government (CTQ2015-64561-R), CCC-UAM (computing time), and ERC (ERC-CG, 647550, 648319) is acknowledged. L.M., R.P-R, and R.C. thank CAM for the "Atracción de Talento" fellowship. The authors thank "Comunidad de Madrid" and European Structural Funds for their financial support to FotoArt-CM project (S2018/NMT-4367). We thank Miguel Ángel Miranda for helpful discussions about photochemical mechanisms.

[EN] Sunlight plays a critical role in the development of emerging sustainable energy conversion and storage technologies. Light-induced CO2 reduction by artificial photosynthesis is one of the cornerstones to produce renewable fuels and environmentally friendly chemicals. Interface interactions between plasmonic metal nanoparticles and semiconductors exhibit improved photoactivities under a wide range of the solar spectrum. However, the photoinduced charge transfer processes and their influence on photocatalysis with these materials are still under debate, mainly due to the complexity of the involved routes occurring at different timescales. Here, we use a combination of advanced in situ and time-resolved spectroscopies covering different timescales, combined with theoretical calculations, to unravel the overall mechanism of photocatalytic CO2 reduction by Ag/TiO2 catalysts. Our findings provide evidence of the key factors determining the enhancement of photoactivity under ultraviolet and visible irradiation, which have important implications for the design of solar energy conversion materials. ; This work has received funding from the European Research Council (ERC), within the projects Intersolar (291482) and HyMAP programme (648319) under the European Union's Horizon 2020 research and innovation programme. The results reflect only the authors' view and the Agency is not responsible for any use that may be made of the information they contain. V.A.P.O. thanks funding from the Spanish Ministry of Economy and Competitiveness (project ENE2016-79608-C2-1-R). A.R. acknowledges the European Commission Marie Curie CIG. M.B. acknowledges the Juan de la Cierva Formación program: FJCI-2016-30567, V.A.P.O. acknowledges support from the Centre of Supercomputacio de Catalunya (CESCA) and to ALBA Cells Synchrotron facilities. Authors thank Dr. Xiaoe Li for assistance in TiO2 films preparation. Support from the Repsol Technology Centre in gratefully acknowledged. ; Peer reviewed