Regioselectivity in Pyrene-Templated Polymerization\nUsing MOFs as 1D Porous Scaffolds

Physicochemical properties of polymers strongly depend on the arrangement\nand distribution of attached monomers. Templated polymerization using\nporous crystalline materials appears as a promising route to gain\ncontrol on the process. Thus, we demonstrate here the potential of\nmetal–organic frameworks as scaffolds with a versatile and\nvery regular porosity, well adapted for the regioselective oxidative\npolymerization of pyrene. This photoresponsive monomer was first encapsulated\nwithin the one-dimensional (1D) microporosity of the robust zirconium(IV)\ncarboxylate metal–organic framework (MOF) (MIL-140D) to, later,\nundergo <i>in situ</i> oxidative polymerization, enabling\nthe growth of a highly selective polypyrene (PPyr) regioisomer over\nother potential polymer configurations. To confirm the polymerization\nand the geometry control of pyrene, the resulting composites were\nexhaustively characterized by powder X-ray diffraction (PXRD), thermogravimetric\nanalysis (TGA), N<sub>2</sub> sorption measurements, scanning transmission\nelectron microscopy coupled with energy-dispersive X-ray (STEM-EDX)\nspectroscopy, and fluorescence spectroscopy. Among others, photoluminescence\nquenching and emission shift in the solid state demonstrated the presence\nof PPyr inside the MOF porosity. Furthermore, an in-depth joint analysis\ncombining solid-state, magic-angle spinning (MAS) <sup>1</sup>H and <sup>13</sup>C NMR spectroscopy, Fourier transform infrared (FTIR) spectroscopy,\nmatrix-assisted laser desorption/ionization time-of-flight mass spectroscopy\n(MALDI-TOF MS), and molecular simulations (grand canonical Monte Carlo\n(GCMC) and density functional theory (DFT)) allowed the elucidation\nof the spatial, host–guest interactions driving the polymerization\nreaction.