Description:
The synthesis and characterization of an isomorphous series of copper-containingmicroporous metal-organic frameworks (MOFs) based on triazolyl isophthalate linkers with thegeneral formula 3¥[Cu4(m3-OH)2(R1-R2-trz-ia)3(H2O)x] are presented. Through size adjustmentof the alkyl substituents R1 and/or R2 at the linker, the impact of linker functionalization onstructure-property relationships was studied. Due to the arrangement of the substituents towards thecavities, the porosity (pore fraction 28%–39%), as well as the pore size can be adjusted by the size of thesubstituents of the triazole ring. Thermal analysis and temperature-dependent PXRD studies reveal athermal stability of the MOFs up to 230 C due to increasing framework stability through fine-tuningof the linker substitution pattern. Adsorption of CO2 (298 K) shows a decreasing maximum loadingwith increasing steric demand of the substituents of the triazole ring. Furthermore, the selectiveoxidation of cyclohexene with tert-butyl hydroperoxide (TBHP) is studied over the MOFs at 323 Kin liquid chloroform. The catalytic activity increases with the steric demand of the substituents.Additionally, these isomorphous MOFs exhibit considerable robustness under oxidizing conditionsconfirmed by CO2 adsorption studies, as well as by the catalytic selective oxidation experiments.