P1-0021 — Annual report 2015
1.
A simple NMR-based method for studying the spatial distribution of linkers within mixed-linker metal-organic frameworks

We developed a new method for the investigation of spatial distribution of various organic linkers or functional groups within MOFs. The method is based on NMR measurement of spin-diffusion rates and modelling of distributions of organic linkers within MOFs. It can distinguish between the cases, in which different linkers form domains, and cases, in which different linkers are uniformly distributed throughout the materials, which crucially effects their sorption performance. This unique tool can be employed also for studying other heterogeneous or spatially disordered materials.

COBISS.SI-ID: 5735962
2.
In situ generation of Ni nanoparticles from metal-organic framework precursors and their use for biomass hydrodeoxygenation

Metal-organic framework precursor MIL-77(Ni) was developed for in situ generation of Ni nanoparticles with high hydrodeoxygenation activity and efficiency for conversion of wood-derived oil into the polar and non-polar phase with a significantly lower viscosity and oxygen content compared to known procedures. The research achievement represents a key step in the design of catalysts for the sustainable conversion of biomass to fuels and chemicals in biorefineries.

COBISS.SI-ID: 5667866
3.
Structural study of Mg-based metal-organic frameworks by X-ray diffraction, 1H, 13C and 25Mg solid-state NMR spectroscopy, and first-principles calculations

We studied three polycrystalline Mg–benzene–1,3,5-tricarboxylates, differing in the dimensionality of their frameworks by XRD, NMR and first-principles calculations to better understand their formation principles, structure and stability. 25Mg, 13C, and 1H MAS NMR spectra confirmed the proposed XRD-based structural models, elucidated hydrogen bonds within the two materials, and detected the strong effect of the anisotropy of the bulk magnetic susceptibility in one. DFT-based calculation of formation energies of the materials enabled the prediction of the thermodynamical stability of their structures.

COBISS.SI-ID: 37867269
4.
Pore occupancy changes water/ethanol separation in a metal-organic framework-quantitative map of coadsorption by IR

The conventional distillation method to separate ethanol from water is energy-intensive and inefficient due to the presence of the azeotropic point of the binary system. Preferential-adsorption-based separation is considered to be an efficient and energy-saving method for purification due to the easy regeneration under relatively mild conditions. In our work, the coadsorption of gaseous water and ethanol on a porous metal–organic framework [MIL-100(Fe)] in various proportions was studied by inovative coupling of FTIR spectroscopy with in situ gravimetry (AGIR) under different conditions (P/Po). Ethanol was preferentially adsorbed on MIL-100(Fe). Our results showed that the optimal conditions for the separation of H2O/EtOH on MIL-100(Fe) was at EtOH(P/Po)(0.05 with H2O(P/Po)(0.4 at room temperature.

COBISS.SI-ID: 5760026
5.
Phase formation study of Ca-terephthalate MOF-type materials

We studied the formation of two crystalline phases of Ca(BDC)(DMF)(H2O) compound with systematic variations of synthesis conditions. The compund with square lattice topology and rhombic-shaped channels crystallizes under solvothermal conditions (H2O/DMF mixture) into orthorhombic (Ca-BDC-orth) and/or triclinic (Ca-BDC-tric) phase. The latter structure was solved and described in our study for the first time. The main difference between the two phases lies in the orientation of the coordinated DMF molecule located within the channels of the structure, influencing their porosity properties. In spite of the small deviances in crystal structure, we showed that the formation of individual phases can be well-controlled by the amount of base agent (TEA) and the temperature of crystallization as well as that the stability of selected phase is related to the thermodynamics at equilibrium conditions.

COBISS.SI-ID: 5636890