RESUMEN
Synthetic porous materials continue to garner attention as platforms for solid-state chemistry and as designer heterogeneous catalysts. Applications in photochemistry and photocatalysis, however, are plagued by poor light harvesting efficiency due to light scattering resulting from sample microcrystallinity and poor optical penetration that arises from inner filter effects. Here we demonstrate the layer-by-layer growth of optically transparent, photochemically active thin films of porous salts. Films are grown by sequential deposition of cationic Zr-based porous coordination cages and anionic Mn porphyrins. Photolysis facilitates the efficient reduction of Mn(III) sites to Mn(II) sites, which can be observed in real-time by transmission UV-vis spectroscopy. Film porosity enables substrate access to the Mn(II) sites and facilitates reversible O2 activation in the solid state. These results establish optically transparent, porous salt thin films as versatile platforms for solid-state photochemistry and in operando spectroscopy.
RESUMEN
Atomistic control of the coordination environment of lattice ions and the distribution of metal sites within crystalline mixed-metal coordination polymers remain significant synthetic challenges. Herein is reported the mechanochemical synthesis of a reticular family of crystalline heterobimetallic metal-organic frameworks (MOFs) is now achieved by polymerization of molecular Ru2 [II,III] complexes, featuring unprotected carboxylic acid substituents, with Cu(OAc)2 . The resulting crystalline heterobimetallic MOFs are solid solutions of Ru2 and Cu2 sites housed within [M3 L2 ] phases. The developed mechanochemical strategy is modular and allows for systematic control of the primary coordination sphere of the Ru2 sites within an isoreticular family of materials. This strategy is anticipated to provide a rational approach to atomically precise mixed-metal materials.
RESUMEN
We present a family of covalent organic frameworks that have been functionalized with oligo-(ethylene oxide) chains of varying lengths. Because of the open structure of the COFs, the side chains do not interfere with their crystallization obtaining materials with predictable crystal structure. The difference in length of the side-chains allowed for the determination of amphidynamic behaviour with the use of 13C solid-state NMR relaxation methods. Computational calculations further contribute to understanding the atomistic dynamic behaviour of the different atoms. This study demonstrates the ability to design complex behaviour in organic crystals.
