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Titanium containing aminoterephthalate metal organic framework promotes the photocatalytic overall water splitting into H2 and O2 at a rate that depends on the presence of Pt, RuO2 and CoOx co-catalyst. The best values of have been obtained for the MIL-125-NH2 material that contains Pt and RuO2, reaching a production of 218 and 85 µmol/g photocatalyst -1 at 24 h for H2 and O2, respectively.

The assumption that oxidative addition is the key step during the cross-coupling reaction of aryl halides has led to the development of a plethora of increasingly complex metal catalysts, obviating in many cases the exact influence of the base, the simplest, inexpensive and necessary reagent for this paramount transformation. Here, a combined experimental and computational study shows that the oxidative addition is not any more the controlling step during different cross-coupling reactions if catalyzed by ligand-free sub-nanometer Pd or Pt clusters, translating reactivity control to subtle changes in the base, i.e. acetate drives to the Heck, carbonate to the Sonogahira and phosphate to the Suzuki reaction. For that, the exposed metal atoms in the cluster cooperate to enable an extremely easy oxidative addition of the aryl halide, even chlorides, and allows the base to bifurcate the coupling. This base-controlled orthogonal reactivity with ligand-free catalysts open new avenues in the design of cross-coupling reactions in organic synthesis.

A new porous titanium(IV) squarate metal–organic framework (MOF), denoted as IEF‐11, having a never reported titanium secondary building unit, is successfully synthesized and fully characterized. IEF‐11 not only exhibits a permanent porosity but also an outstanding chemical stability. Further, as a consequence of combining the photoactive Ti(IV) and the electroactive squarate, IEF‐11 presents relevant optoelectronic properties, applied here to the photocatalytic overall water splitting reaction. Remarkably, IEF‐11 as a photocatalyst is able to produce record H2 amounts for MOF‐based materials under simulated sunlight (up to 672 µmol gcatalyst in 22 h) without any activity loss during at least 10 d.

Defect engineering in metal‐organic frameworks is commonly performed by using thermal or chemical treatments. Herein we report that oxygen plasma treatment generates structural defects on MIL‐125(Ti)‐NH2, leading to an increase in its photocatalytic activity. Characterization data indicate that plasma‐treated materials retain most of their initial crystallinity, while exhibiting somewhat lower surface area and pore volume. XPS and FT‐IR spectroscopy reveal that oxygen plasma induces MIL‐125(Ti)‐NH2 partial terephthalate decarboxylation and an increase in the Ti‐OH population. Thermogravimetric analyses confirm the generation of structural defects by oxygen plasma and allowed an estimation of the resulting experimental formula of the treated MIL‐125(Ti)‐NH2 solids. SEM analyses show that oxygen plasma treatment of MIL‐125(Ti)‐NH2 gradually decreases its particle size. Importantly, diffuse reflectance UV/Vis spectroscopy and valence band measurements demonstrate that oxygen plasma treatment alters the MIL‐125(Ti)‐NH2 band gap and, more significantly, the alignment of highest occupied and lowest unoccupied crystal orbitals. An optimal oxygen plasma treatment to achieve the highest efficiency in water splitting with or without methanol as sacrificial electron donor under UV/Vis or simulated sunlight was determined. The optimized plasma‐treated MIL‐125(Ti)‐NH2 photocatalyst acts as a truly heterogeneous photocatalyst and retains most of its initial photoactivity and crystallinity upon reuse.

A novel microporous 2D Ni-based phosphonate metal-organic framework (MOF; denoted as IEF-13) has been successfully synthesized by a simple a green hydrothermal method and fully characterized using a large panel of experimental and computational techniques. From structural resolution from single-crystal X-ray diffraction, IEF-13 crystallizes in the triclinic space group P-1 based on bi-octahedra nickel nodes and a photo/electroactive tritopic phosphonate ligand. Remarkably, this material exhibits coordinatively unsaturated ni ckel(II) sites, free -PO3H2 and -PO3H acidic groups, a CO2 accessible microporosity, and an exceptional thermal and chemical stability. Further, its in-deep optoelectronic characterization evidences a photoresponse suitable for photocatalysis. In this sense, the photocatalytic activity for challenging H2 generation and overall water splitting has been pioneering evaluated for a phosphonate-MOF in absence of any co-catalyst using UV-Vis irradiation and simulated sunlight. IEF-13 is able to produce up to 2200 mol of H2•g -1 using methanol as sacrificial agent, whereas remaining stable and allowing recycling. preserving its crystalline structure. Even more, 170 mol of H2•g -1 were produced using IEF-13 as photocatalyst in absence of any co-catalyst in the more challenging overall water splitting, being this reaction limited by the O2 reduction. Thus, this original work opens new avenues to further optimize the photocatalytic activity of this type of multifunctional materials.

Isophthalic acid (IPA), a feedstock linker, has been considered so far to build series of topical metal-organic frameworks (MOFs) of diverse structures with various di-and trivalent metal ions, such as CAU-10(Al), owing to its facile availability, unique connection angle/mode and a wide scope of functional groups attached. Constructing MOFs from IPA and tetravalent metals, typically Group 4 metals, would be of a great interest due to expected higher chemical stability. In particular, titanium-IPA frameworks possessing photoresponse is alluring, in relation to the known challenge of synthesizing new Ti-MOFs. Here, we have synthesized the first Ti-IPA MOF, denoted as MIP-208, via a solvothermal process that efficiently combines the use of preformed Ti 8 oxoclusters and in situ acetylation of 5-NH 2 -IPA linker. MIP-208 has helical chains of cis-connected corner-sharing TiO 6 polyhedra as the inorganic building units, which are interconnected to each other leading to a 3D ultramicroporous framework. Solid-solution mixed linkers strategy was then successfully applied resulting in a series of multivariate MIP-208 structures with tunable chemical environment and sizable porosity. Finally, the excellent thermal and hydrolytic stabilities of MIP-208 allowed its use for the photocatalytic carbon dioxide (CO 2 ) methanation, showing the best result among the pure MOF catalysts. Ruthenium oxide nanoparticles were further photodeposited on MIP-208 forming a highly active and selective composite catalyst, MIP-208@RuO x , to largely improve the photocatalytic performance, which features a notable visible light response, an excellent stability and recycling ability.

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