A combination of quantum and classical calculations have been performed in order to investigate hydrogen storage in metal-organic frameworks (MOFs) modified by lithium alkoxide groups. Ab initio calculations showed that the interaction energies between the hydrogen molecules and this functional group are up to three times larger compared with unmodified MOF. This trend was verified by grand canonical Monte Carlo (GCMC) simulations in various thermodynamic conditions. The gravimetric capacity of the Li-modified MOFs reached the value of 10 wt % at 77 K and 100 bar, while our results are very promising at room temperature, too, with 4.5 wt %.

A novel computational methodology for large-scale screening of MOFs is applied to gas storage with the use of machine learning technologies. This approach is a promising trade-off between the accuracy of ab initio methods and the speed of classical approaches, strategically combined with chemical intuition. The results demonstrate that the chemical properties of MOFs are indeed predictable (stochastically, not deterministically) using machine learning methods and automated analysis protocols, with the accuracy of predictions increasing with sample size. Our initial results indicate that this methodology is promising to apply not only to gas storage in MOFs but in many other material science projects.npj Computational Materials (2017) 3:40 ; doi:10.1038/s41524-017-0045-8 INTRODUCTION Metal-organic frameworks (MOFs) or porous coordination polymers are a rapidly growing family of hybrid inorganic-organic nanoporous materials, which belong to the category of coordination polymers.1-3 These relatively new materials consist of a threedimensional periodic network, constructed from molecular building blocks, such as metal clusters and organic linkers (Fig. 1). The possible combinations of these numerous building blocks under different topologies result is an almost unlimited number of potential MOFs! Since their discovery 4 MOFs have attracted significant scientific attention due to their extraordinary properties. As "skeleton" materials, they pose very large pores and outstanding apparent surface area. If we were able to unwrap the surface of only one gram of these "very empty" materials, we could cover the area of a football court! These unique characteristics of the MOFs made them excellent candidates for catalysis and gas storage applications.MOFs have shown exceptional performance in gas storage and separation. Both useful and harmful gases can be absorbed in their pores in very large amounts. The storage of hydrogen,

A multiscale theoretical approach is used for the investigation of hydrogen storage in three-dimensional covalent organic frameworks (3D-COFs). First, ab initio calculations were performed at the density functional level of theory, accompanied with more accurate MP2 calculations to obtain the hydrogen binding sites in these recently synthesized ultralight materials with large surface areas. Second, classical grand canonical Monte-Carlo simulations were carried out to obtain the hydrogen uptake of these frameworks under different thermodynamic conditions. Our results demonstrate that the gravimetric uptake of COFs is in some cases 2 times larger than that of the best known metal-organic frameworks while the volumetric remains comparable. Especially for COF-108, the gravimetric uptake has reached the value of 21 wt % in 77 K and 100 bar conditions and the very promising value of 4.5 wt % at room temperature and 100 bar conditions.

Hydrogen storage properties have been studied on newly designed three-dimensional covalent-organic framework (3D-COF). The design of these materials was based on the ctn network of the ultralow density COF-102. The structures were optimized by multiscale techniques and the optimized structures were checked for their storage capacities by grand canonical Monte Carlo simulations. Our simulations demonstrate that the gravimetric uptake of one of these new COFs can overpass the value of 25 wt % in 77 K and reach the Department of Energy's target of 6 wt % in room temperature, classifying them between the top hydrogen storage materials.

The boron dipyrrin (Bodipy) chromophore was combined with either a free-base or a Zn porphyrin moiety (H(2)P and ZnP respectively), via an easy synthesis involving a cyanuric chloride bridging unit, yielding dyads Bodipy-H(2)P (4) and Bodipy-ZnP (5). The photophysical properties of Bodipy-H(2)P (4) and Bodipy-ZnP (5) were investigated by UV-Vis absorption and emission spectroscopy, cyclic voltammetry, and femtosecond transient absorption spectroscopy. The comparison of the absorption spectra and cyclic voltammograms of dyads Bodipy-H(2)P (4) and Bodipy-ZnP (5) with those of their model compounds Bodipy, H(2)P, and ZnP shows that the spectroscopic and electrochemical properties of the constituent chromophores are essentially retained in the dyads indicating negligible interaction between them in the ground state. In addition, luminescence and transient absorption experiments show that excitation of the Bodipy unit in Bodipy-H(2)P (4) and Bodipy-ZnP (5) into its first singlet excited state results in rapid Bodipy to porphyrin energy transfer-k(4) = 2.9 × 10(10) s(-1) and k(5) = 2.2 × 10(10) s(-1) for Bodipy-H(2)P (4) and Bodipy-ZnP (5), respectively-generating the first porphyrin-based singlet excited state. The porphyrin-based singlet excited states give rise to fluorescence or undergo intersystem crossing to the corresponding triplet excited states. The title complexes could also be used as precursors for further substitution on the third chlorine atom on the cyanuric acid moiety.