Postsynthetic ionization of an imidazole-containing metal–organic framework for the cycloaddition of carbon dioxide and epoxides† †Electronic supplementary information (ESI) available: General comments, syntheses and characterizations of the MOFs mentioned in the manuscript, details of the single crystal diffraction experiments, PXRD, TG and additional figures. CCDC 1499016. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc04357g Click here for additional data file. Click here for additional data file.

1. General experiments 2-(imidazol-1-yl)terephthalic acid (Im-H 2 BDC • HCl) was prepared by a similar process according to the literature. 1 Other reagents were purchased from commercial sources and used as received. N 2 and CO 2 sorption isotherms of Im-UiO-66 (1) and (I-)Meim-UiO-66 (2) were measured by using a Micrometrics ASAP 2420 instrument at 77 K and 273K, 298 K, respectively. Before the measurement, the samples were evacuated and activated at 393 K in vacuum for 10 h. Adsorption enthalpies for CO 2 of 1 and 2 were calculated by virial method in Origin software. Powder X-ray diffraction patterns (PXRD) were recorded on a Rigaku Dmax 2500 diffractometer equipped with Cu-Kαradiation (λ= 1.54056 Å) over the 2θ range of 5–45° with a scan speed of 3 ° min −1 at room temperature. Thermogravimetric analyses (TGA) were performed under a nitrogen atmosphere with a heating rate of 10°C min −1 by using an SDT Q600 thermogravimetric analyser. The samples were activated at 393 K in vacuum for 10 h before TGA test. Infrared (IR) spectra were recorded using KBr pellets on a PerkinElmer Spectrum One in the range of 400–4000 cm −1. Elemental analyses of C, H, and N were carried out on an Elementar Vario EL III analyzer. The