Microporous Mixed‐Metal Layer‐Pillared [Zn_1–<i>x</i>Cu<i>_x</i>(bdc)(dabco)_0.5] MOFs: Preparation and Characterization

Abstract

Abstract A series of mixed‐metal layer‐pillared MOFs of general formula [Zn 1– x Cu x (bdc)(dabco) 0.5 ] (bdc = 1,4‐benzenedicarboxylate, dabco = 1,4‐diazabicyclo[2.2.2]octane, 0 &lt; x &lt; 1) have been synthesized by a solvothermal approach. Different amounts x of Cu 2+ were introduced to substitute for Zn 2+ centers. The prepared mixed‐metal MOFs were shown to be structurally very similar to their parent monometallic [Zn(bdc)(dabco) 0.5 ] and [Cu(bdc)(dabco) 0.5 ] frameworks by single‐crystal and powder X‐ray diffraction studies. Interestingly, upon inclusion of copper, a distortion of the paddle‐wheel units is observed. In addition, the incorporation of Cu 2+ ions into the [Zn 2 (bdc)(dabco) 0.5 ] framework and the formation of heterometallic Zn–Cu paddle‐wheel units along with monometallic Cu–Cu and Zn–Zn units in the prepared mixed‐metal MOFs were confirmed by continuous‐wave EPR spectroscopy. The synthesized materials [Zn 1– x Cu x (bdc)(dabco) 0.5 ] are thermally stable up to 260 °C and exhibit permanent porosity with BET surface areas in the range of 800–2430 m 2 g –1 .