Microporous Mixed‐Metal Layer‐Pillared [Zn_1–xCu_x(bdc)(dabco)_0.5] MOFs: Preparation and Characterization

Abstract

A series of mixed‐metal layer‐pillared MOFs of general formula [Zn1–xCux(bdc)(dabco)0.5] (bdc = 1,4‐benzenedicarboxylate, dabco = 1,4‐diazabicyclo[2.2.2]octane, 0 < x < 1) have been synthesized by a solvothermal approach. Different amounts x of Cu2+ were introduced to substitute for Zn2+ 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 Cu2+ ions into the [Zn2(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 [Zn1–xCux(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 m2 g–1.

A Solid‐Solution Approach to Mixed‐Metal Metal–Organic Frameworks – Detailed Characterization of Local Structures, Defects and Breathing Behaviour of Al/V Frameworks

“…Although the overall structure of the parent framework(s) is preserved, the insertion of a second kind of metal ion causes distortion of the local metal coordination environment in MC‐MOFs, even in low amounts, as we have recently shown for [Zn 1– x Cu x (bdc)(dabco) 0.5 ] n (bdc = 1,4‐benzenedicarboxylate, dabco = 1,4‐diazabicyclo[2.2.2]octane) 9d. Following our previous studies, herein we provide a detailed systematic study on metal‐cation doping in MOFs to address an important issue of composition–structure correlations in general as well as the (intrinsic) local structural “defects” that may occur in such complex systems and how they subsequently reflect on the properties of the material.…”

Pillared-layered metal–organic frameworks for mechanical energy storage applications

“…This material has been synthesized with various types of metal ions (Fe, 32 Co, 33,34 Ni, 35,36 Cu, 28 Zn 29 ) and mixed-metal variants exist. 37 While theoretical investigations of DMOF-1 are relatively limited, 5,17,21,38,39 the unusual and reversible breathing behavior has been highlighted by several experimental groups. 29,[40][41][42][43][44][45][46][47][48][49][50][51][52][53][54] On the one hand, with guests present in the pores, DMOF-1(Zn) was found to contract upon adsorption.…”

Simultaneous introduction of various palladium active sites into MOF via one-pot synthesis: Pd@[Cu3−xPdx(BTC)2]n

“…17,18 Combination of distinct metal-ions, which are closely related in coordination chemistry and have similar effective ionic radii (r ion ), such as Cu 2+ (73 pm)/Zn 2+ (74 pm) couple 19 within single MOF, has been reported for several structural types. 17,20,21 In fact, partial substitution of Cu 2+ by Zn 2+ and some other metals of 3d-row, namely, Co, Fe and Mn, in HKUST-1 ([Cu 3 (BTC) 2 ] n , BTC = benzene-1,3,5-tricarboxylate) has been recently reported. 18,22 In a later case, doping with a second metal caused enhanced selective sorption of O 2 vs. N 2 .…”