Tuning Light Emission and Dynamics of Gases in Porous Materials

The present contribution will be an overview of porous materials as radiation frequency converters, by integration of acceptor and donor into a single framework, for light upgrading and downgrading. Two active components will be co-assembled in varied molar fractions to reach the optimal balance. A few strategies of bond formation will be compared to form mix-ligand MOFs and PAFs. In some instances, even three components, each with its own function, can be comprised in the structures. The chromophore density and the distance between donors and acceptors can be fine-modulated, for benchmark efficiency. Morphology and size of the nanocrystals was also a parameter kept under control and excitation diffusion was modelled. Additionally, dynamics in porous materials will be addressed in detail by spectroscopic techniques: fast molecular reorientation and, specifically, dipole reorientation is a challenging task as explored in conjunction with gas diffusion. CO2 and Xe learn during diffusion steps, the shape and orientation of the channels, as detected by anisotropic line-shape analysis of 13C and hyperpolarized 129Xe NMR resonances. These spectroscopic observations, together with DFT and molecular dynamics simulations, help understand gas sorption and measure diffusion times by jump frequency of the gas species from site to site in the material, through orientation imprinting. Overall, a structure-property comparison among porous systems, from metal-organic to covalent and molecular porous materials, will be traced as regards the potentials to realize the desired performances. 1) Nature Photonics 2021 https://doi.org/10.1038/s41566-021-00769-z 2) Adv. Mater. 2019, 31, 1903309 3) Chem. Sci., 2019, 10, 730