Metal-ligand cooperative properties of a bis-N-heterocyclic carbene ruthenium CNC pincer catalyst and its activity in CO2 hydrogenation to formates were studied by DFT calculations complemented by NMR spectroscopy and kinetic measurements. The dearomatized Ru-CNC∗ pincer (1∗) is significantly more reactive toward metal-ligand cooperative activation of H2 and CO2 than the structurally related phosphine-based Ru-PNP complex. The enhanced reactivity of Ru-CNC∗ stems from the combination of electronic properties of this system and the reduced geometric constraints imposed onto the Ru center by the large and flexible CNC chelate. Heterolytic dissociation of H2 by 1∗ results in the bis-hydrido complex 2 that is active in hydrogenation of CO2. However, under commonly applied reaction conditions, the catalyst rapidly deactivates via metal-ligand cooperative paths. The transient formation of the dearomatized complex Ru-CNC∗ (1∗) in the course of the reaction leads to the irreversible cooperative activation of CO2, resulting in the stable adduct 3 that is not catalytically competent. By an increase in the H2/CO2 ratio, this deactivation path can be effectively suppressed, resulting in a stable and rather high catalytic performance of Ru-CNC. (Chemical Equation Presented).@en

In applying a multi-scale spectroscopic and computational approach, we demonstrate that the synthesis of stacked zeolite silicalite-1 nanosheets, in the presence of a long-tail diquaternary ammonium salt surfactant, proceeds through a pre-organised phase in the condensed state. In situ small-angle X-ray scattering, coupled to paracrystalline theory, and backed by electron microscopy, shows that this phase establishes its meso-scale order within the first five hours of hydrothermal synthesis. Quasi in situ vibrational and solid-state NMR spectroscopy reveal that this meso-shaped architecture already contains some elementary zeolitic features. The key to this coupled organisation at both micro- and meso-scale, is a structure-directing agent that is ambifunctional in shaping silica at the meso-scale whilst involved in molecular recognition at the micro-scale. The latter feature is particularly important and requires the structure-directing agent to reside within the silica matrix already at early stages of the synthesis. From here, molecular recognition directs stabilization of precursor species and their specific embedding into a lattice, as shown by force-field molecular dynamics calculations. These calculations, in line with experiment, further show how it is possible to subtly tune both the zeolite topology and aspect ratio of the condensating crystals, by modifying the headgroup of the structure-directing agent.@en

This paper reports for the first time a computational analysis of the redox properties of graphene-supported Ru-porphyrins as potential catalytic materials for electrochemical CO2 reduction. Density functional theory reveals that such catalytic ensembles can efficiently activate both CO2 and CH4 molecules indicating their generic utility as C1-functionalization catalysts. The charge transfer from the graphene surface to the catalytic Ru centers influences the thermodynamic stability of the key reaction intermediates and therefore determines the selectivity of the electrochemical process. The electrochemical reduction of CO2 can yield CO or methane, depending on the applied potential and reaction conditions. Calculations also identified alternative paths towards methanol and formic acid.@en