Post-Synthetic Modification of a 1D Mixed-Linker Zn(II) Coordination Polymer for Acid-Catalyzed Alcoholysis of Epoxides

Rational design of heterogeneous acid catalysts possessing uniform dispersion of active sites plays a significant role in the catalytic performance. In the present work, a coordination polymer, [Zn(4,4'-bpy)(mu-Hbtc)(H2O)] & sdot; 2H2O (Zn-CP), was solvothermally synthesized using 4,4'-bpy (=4,4'-bipyridine) and H3btc (=1,3,5-benzenetricarboxylic acid) mixed linkers. Single crystal X-ray analysis of the polymer displayed that Zn-CP chains were decorated with 4,4'-bpy having unidentate coordination fashion. Then, the free N atom of the linker in Zn-CP was functionalized by -SO3H groups to afford Zn-CP-SO3H with enhanced acidity. The structures were characterized by FT-IR, thermogravimetric analysis, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature programmed desorption of NH3 (NH3-TPD), and field emission scanning electron microscopy (FE-SEM) analyses. The coordination polymer was employed as a heterogeneous catalyst for the alcoholysis of epoxides under room conditions. Zn-CP-SO3H exhibited excellent catalytic activity and regioselectivity in the methanolysis of styrene oxide within short reaction time.