Owing to their promise in photocatalysis and optoelectronics, titanium based metal-organic frameworks (MOFs) are one of the most appealing classes of MOFs reported to date. Nevertheless, Ti-MOFs are still very scarce because of their challenging synthesis associated with a poor degree of control of their chemistry and crystallization. This review aims at giving an overview of the recent progress in this field focusing on the most relevant existing titanium coordination compounds as well as their promising photoredox properties. Not only Ti-MOFs but also Ti-oxo-clusters will be discussed and particular interest will be dedicated to highlight the different successful synthetic strategies allowing to overcome the still "unpredictable" reactivity of titanium ions, particularly to afford crystalline porous coordination polymers.

This minireview deals with the recent advances on the synthetic strategies for the immobilization of enzymes in metal–organic frameworks.

The energy-storage capacities of a series of water-stable porous metal-organic frameworks, based on high-valence metal cations (Al , Fe , Cr , Ti , Zr ) and polycarboxylate linkers, were evaluated under the typical conditions of seasonal energy-storage devices. The results showed that the microporous hydrophilic Al-dicarboxylate MIL-160(Al) exhibited one of the best performances. To assess the properties of this material for space-heating applications on a laboratory pilot scale with an open reactor, a new synthetic route involving safer, greener conditions was developed. This led to the production of MIL-160(Al) on a 400 g scale, before the material was shaped into pellets through a wet-granulation method. The material exhibited a very high energy-storage capacity for a physical-sorption material (343 Wh kg ), which is in full agreement with the predicted value.

Porous titanium oxide materials are attractive for energy-related applications. However, many suffer from poor stability and crystallinity. Here we present a robust nanoporous metal–organic framework (MOF), comprising a Ti12O15 oxocluster and a tetracarboxylate ligand, achieved through a scalable synthesis. This material undergoes an unusual irreversible thermally induced phase transformation that generates a highly crystalline porous product with an infinite inorganic moiety of a very high condensation degree. Preliminary photophysical experiments indicate that the product after phase transformation exhibits photoconductive behavior, highlighting the impact of inorganic unit dimensionality on the alteration of physical properties. Introduction of a conductive polymer into its pores leads to a significant increase of the charge separation lifetime under irradiation. Additionally, the inorganic unit of this Ti-MOF can be easily modified via doping with other metal elements. The combined advantages of this compound make it a promising functional scaffold for practical applications.

A microporous Al trimesate-based Metal Organic Framework (MOF), denoted MIL-96(Al), was selected as a porous hybrid filler for the processing of Mixed Matrix Membranes (MMMs) for CO 2 /N 2 post combustion separation. First, the structural model of MIL-96(Al) initially reported was revisited using a combination of synchrotron-based single crystal X-ray diffraction (XRD), solid state Nuclear Magnetic Resonance (NMR) spectroscopy and Density Functional Theory (DFT) calculations. In a second step, pure MIL-96 (Al) crystals differing by their size and aspect ratio, including anisotropic hexagonal platelets and nanoparticles of about 70 nm in diameter, were prepared. Then, a combination of in situ IR spectroscopy, single gas and CO 2 /N 2 co-adsorption experiments, calorimetry and molecular simulations revealed that MIL-96(Al) nanoparticles show a relatively high CO 2 affinity over N 2 owing to strong interactions between CO 2 molecules and several adsorption sites such as Al 3+ Lewis centers, coordinated water and hydroxyl groups. Finally, the high compatibility between MIL-96(Al) nanoparticles and the 6FDA-DAM polymer allowed the processing of homogeneous and defect-free MMMs with a high MOF loading (up to 25 wt%) that outperform pure polymer membranes for CO 2 /N 2 separation.

A study integrating advanced experimental and modeling tools was undertaken to characterize the microstructural and interfacial properties of mixed matrix membranes (MMMs) composed of the zeolitic imidazolate framework ZIF-8 nanoparticles (NPs) and two polymers of intrinsic microporosity (PIM-1 and PIM-EA-TB). Analysis probed both the initial ZIF-8/PIM-1 colloidal suspensions and the final hybrid membranes. By combination of dynamic light scattering (DLS) and transmission electron microscopy (TEM) analytical and imaging techniques with small-angle X-ray scattering (SAXS), the colloidal suspensions were shown to consist mainly of two distinct kinds of particles, namely, polymer aggregates of about 200 nm in diameter and densely packed ZIF-8-NP aggregates of a few 100 nm in diameter with a 3 nm thick polymer top-layer. Such aggregates are likely to impart the granular texture of ZIF-8/PIMs MMMs as shown by SEM-XEDS analysis. At the molecular scale, modeling studies showed that the surface coverage of ZIF-8 NPs by both polymers appears not to be optimal with the presence of microvoids at the interfaces that indicates only a moderate compatibility between the polymer and ZIF-8. This study shows that the microstructure of MMMs results from a complex interplay between the ZIF-8/PIM compatibility, solvent, surface chemistry of the ZIF-8 NPs, and the physicochemical properties of the polymers such as molecular structure and rigidity.

precipitates have been synthesized by adding chloride salts MCl or bases MOH to a metavanadate solution which was acidified using a proton exchange resin. As evidenced by X-ray diffraction, these vanadium oxides exhibit the layered structure of the V 2 O 5 ?1.8H 2 O xerogels in which Na + and TMA + cations are intercalated between the layers. These precipitates result from the assembly of ribbon-like particles but in contrast to the V 2 O 5 ?1.8H 2 O xerogels, the particles are no longer stacked on flat surfaces and their assembly is disorganized as evidenced by SEM and TEM. Depending on the final pH of the acidified metavanadate solution, the Na 0.3 V 2 O 5 ?1.5H 2 O phase can be thermodynamically stable or can evolve with time. At a pH . 3, the Na 0.3 V 2 O 5 ?1.5H 2 O phase disappears after a few days and is transformed to the crystalline NaV 3 O 8 ?1.5H 2 O phase. The vanadium oxide phases were all characterized by X-ray diffraction, SEM, TEM, TGA, IR and 51 V MAS NMR.

Microperoxidase-8, a small, peroxidase-type enzyme was successfully immobilized into nanoparticles of the mesoporous and ultra-stable . The immobilized enzyme retained fully its catalytic activity and exhibited enhanced resistance to acidic conditions. The biocatalyst was reusable and showed a long-term stability. By exploiting the properties of the MOF's framework, we demonstrated, for the first time, that the MOF matrix could act in synergy with the enzyme (Microperoxidase-8) and enhance selectivity the oxidation reaction of dyes. The oxidation rate of the harmful negatively charged dye (methyl orange) was significantly increased after enzyme immobilization, most likely due to the preconcentration of the methyl orange reactant due to a charge matching between this dye and the MOF.Enzymes are biomolecules with remarkable catalytic properties essential for specific applications, such as production of biochemicals and biofuels, and for biosensing and bioremediation purposes. [1] Despite many advances in enzyme engineering, they remain expensive and/or fragile entities. As a result, their use in industrial context often requires their immobilization on a solid support to increase their stability and recovery. Many supports have been developed in the last decades, including, but not limited to, biopolymers/synthetic polymers, sol-gel materials, mesoporous silica, carbon materials, [2] and recently Metal-Organic Frameworks (MOFs). [3] These latter are a class of crystalline hybrid porous materials characterized by a vast chemical functionality, exhibiting a large variety of structural features (surface area, pore size, shape, flexibility…). These have sparked a great interest in many applications such as gas storage and separation, heat transfer, biomedicine, sensing and catalysis, among others. [4] As immobilization matrices, they seem promising since the