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Biotemplating is a powerful approach for manufacturing small-scale devices. Here, the assembly of metal-organic framework (MOF) nanocrystals onto biotemplated magnetic helical structures on the cyanobacterium Spirulina platensis is reported. It is demonstrated that the authors' approach is universal and can be used to equip biotemplated structures with different functional MOF systems. The successful assembly of MOF nanocrystals on magnetically coated helical biotemplates is achieved by decorating the magnetic surface with gelatin, a naturally occurring macromolecule with synthon moieties that allows anchoring of the MOF nanocrystals via electrostatic interactions. Furthermore, as gelatin is a thermally responsive material, it can serve to free the magnetic biotemplates from the MOF nanocrystal cargoes. As such, the systems can be used as highly integrated magnetically driven microrobots with multiple functionalities. To this end, the potential of these composite helical architectures is demonstrated as MOF-based small-scale robots with applications in biomedicine and environmental remediation., Advanced Functional Materials, 32 (13), ISSN:1616-3028, ISSN:1616-301X

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.

We use dodecanoic acid as a modulator to yield titanium MOF nanoparticles with good control of size and colloid stability and minimum impact to the properties of the framework to enable direct fabrication of crystalline, porous thin films. ispartof: CHEMICAL COMMUNICATIONS vol:57 issue:72 pages:9040-9043 ispartof: location:England status: published