Search

The precise control on the combination of multiple metal atoms in the structure of metal-organic frameworks (MOFs) endowed by reticular chemistry, allows the obtaining of materials with compositions that are programmed for achieving enhanced reactivity. The present work illustrates how through the transformation of MOFs with desired arrangements of metal cations, multi-metal spinel oxides with precise compositions can be obtained, and used as catalyst precursor for the reverse water-gas shift reaction. The differences in the spinel initial composition and structure, determined by neutron powder diffraction, influence the overall catalytic activity with changes in the process of in situ formation of active, metal-oxide supported metal nanoparticles, which have been monitored and characterized with in situ X-ray diffraction and photoelectron spectroscopy studies., Work at Instituto de Ciencia de Materiales de Madrid–Consejo Superior de Instigaciones Científicas (CSIC) has been supported by the Spanish Research Agency (Agencia Estatal de Investigación, AEI), Projects MAT2016-78465-R and CTQ2017-87262-R. This work was supported by the EU (ERC CoG HyMAP 648319) and Spanish MINECO (ENE2016-79608-C2-1-R). Authors also wish to thank to “Comunidad de Madrid” and European Structural Funds for their financial support to FotoArt-CM project (S2018/NMT-4367). F. G. acknowledges financial support from MINECO Ramón y Cajal program (RyC-2015-18384).

[EN] Solar fuels production is a cornerstone in the development of emerging sustainable energy conversion and storage technologies. Light-induced H2 production from water represents one of the most crucial challenges to produce renewable fuel. Metalorganic frameworks (MOFs) are being investigated in this process, due to the ability to assemble new structures with the use of suitable photoactive building blocks. However, the identification of the reaction intermediates remains elusive, having negative impacts in the design of more efficient materials. Here, we report the synthesis and characterization of a new MOF prepared with the use of bismuth and dithieno[3,2-b:2',3'-d]thiophene-2,6-dicarboxylic acid (DTTDC), an electron-rich linker with hole transport ability. By combining theoretical studies and time-resolved spectroscopies, such as core hole clock and laser flash photolysis measurements, we have completed a comprehensive study at different time scales (fs to-ms) to determine the effect of competitive reactions on the overall H2 production. We detect the formation of an intermediate radical anion upon reaction of photogenerated holes withan electron donor, which plays a key role in the photoelectrocatalytic processes. These results shed new light on the use of MOFs for solar fuel production., This work was supported by the EU (ERC CoG HyMAP 648319) and Spanish MCIU, Ra-Phuel (ENE2016-79608-C2-1-R), SOLPAC (ENE2017-89170-R) FOTOFUEL (ENE2016-82025-REDT) and CTQ2017-87262-R (MCIU/AEI/FEDER, UE). We thank "Comunidad de Madrid" and European Structural Funds for their financial support to FotoArt-CM project (S2018/NMT-4367). F.G., M. L and M. B thank to MINECO and European Social Fund for a Ramón y Cajal contract (RyC-2015-18384, RyC-2015-18677) and Juan de la Cierva Formación contract (FJCI-2016-30567), respectively. We thank Diamond Facilities for the access to synchrotron radiation and CESCA for computational resources.

New azahelicenes having interesting photophysical properties have been prepared in a four-step sequence. These [7]helicenocarbazoles are efficient blue luminophores, demonstrating the utility of gold catalysis in the preparation of advanced materials., Support for this work by the MINECO and FEDER (Projects CTQ2015-65060-C2-1-P, CTQ2015-65060-C2-2-P, and ENE2016- 79608-C2-1-R) is gratefully acknowledged. M.L. thanks MINECO and European Social Fund for a Ramjn y Cajal contract (RyC- 2015-18677). The authors would like to thank V. de la Camara for preliminary studies and Dr. M. Pintado (IQOG-CSIC) for the acquisition of HPLC chromatograms

The chemistry of metal–organic frameworks (MOFs) relies on the controlled linking of organic molecules and inorganic secondary building units to assemble an unlimited number of reticular frameworks. However, the design of porous solids with chemical stability still remains limited to carboxylate or azolate groups. There is a timely opportunity to develop new synthetic platforms that make use of unexplored metal binding groups to produce metal–linker joints with hydrolytic stability. Living organisms use siderophores (iron carriers in Greek) to effectively assimilate iron in soluble form. These compounds make use of hard oxo donors as hydroxamate or catecholate groups to coordinate metal Lewis acids such as iron, aluminum, or titanium to form metal complexes very stable in water. Inspired by the chemistry of these microorganisms, we report the first hydroxamate MOF prepared by direct synthesis. MUV-11 (MUV = materials of Universidad de Valencia) is a crystalline, porous material (close to 800 m2·g–1) that combines photoactivity with good chemical stability in acid conditions. By using a high-throughput approach, we also demonstrate that this new chemistry is compatible with the formation of single-crystalline phases for multiple titanium salts, thus expanding the scope of accessible precursors. Titanium frameworks are regarded as promising materials for photocatalytic applications. Our photoelectrochemical and catalytic tests suggest important differences for MUV-11. Compared to other Ti-MOFs, changes in the photoelectrochemical and photocatalytic activity have been rationalized with computational modeling, revealing how the chemistry of siderophores can introduce changes to the electronic structure of the frontier orbitals, relevant to the photocatalytic activity of these solids., This work was supported by Spanish MINECO (MDM-2015-0538, CTQ2017-83486-P, and ENE2016-79608-C2-1-R). C.M.-G., N.M.P., J.C.-G., and M.B. thank the Spanish MINECO for a Ramón y Cajal Fellowship (RYC-2012-10894),Marie Skłodowska Curie Fellowship (H2020-MSCA-IF-2016-GF-749359-EnanSET), FPI Scholarship (CTQ2014-59209-P), and Juan de la Cierva Fellowship (FJCI-2016-30567),respectively.