Functionalization of UiO-66 metal-organic framework and highly cross-linked polystyrene with Cr(CO)₃: In situ formation, stability, and photoreactivity

The formation and stability of (arene)Cr(CO)₃ species inside two highly porous materials-UiO-66, which is a recently synthesized metal-organic framework, and a cross-linked poly(styrene-co-divinylbenzene) resin-are investigated in detail by means of complementary spectroscopic techniques and theoretical calculations. In particular, Fourier transform infrared (FT-IR), ultraviolet-visible (UV-vis), and X-ray absorption near-edge structure (XANES) spectroscopies, coupled with theoretical calculations, allow the formation of the (arene)Cr(CO)₃ species to be followed in situ, starting from the Cr(CO)₆ precursor, monitoring the changes in the vibrational and electronic properties of the materials. EXAFS spectroscopy gives the structural evidence of the functionalized unities. Finally, the photoinduced reactivity of Cr(CO)₃ in UiO-66 is also explored, by following the substitution of one CO ligand with a N₂ molecule. The overall presented data would become the starting point for the development of a systematic procedure for investigating functionalized porous matrices.