Structure property relationships affecting the proton conductivity in imidazole loaded Al-MOFs

Abstract

The structures of the imidazole loaded derivatives of Al-MIL-53 [Al(OH)(1,4-BDC-(CH))] (x = 0, 1, 2) and CAU-11 ([Al(OH)(SDBA)]) (1,4-HBDC = terephthalic acid; HSDBA = 4,4'-sulfonyldibenzoic acid) were determined from powder X-ray diffraction data. Impedance spectroscopy measurements were carried out to evaluate their proton conductivities under anhydrous conditions at temperatures up to 110 °C. In Al-MIL-53-(CH)_HIm (x = 0, 1, 2) the formation of hydrogen bonds between the framework and the guest molecules results in a decrease in proton conductivity (x = 1.7 × 10, x = 1.9 × 10 and x = 1.7 × 10 S cm at 110 °C and E = 0.42, 0.41 and 0.46 eV, for 0, 1 and 2 CH-groups, respectively). The highest conductivity has been measured for CAU-11_HIm with 3.0 × 10 S cm at 110 °C (E = 0.19 eV), where no host-guest hydrogen bonding interactions are observed.

Control of Proton‐Conductive Behavior with Nanoenvironment within Metal–Organic Materials

“…Increase in Carrier Concentration (n): Again, as described in the Section 2, a higher concentration of proton sources and/or Reproduced with permission. [103] Copyright 2016, Royal Society of Chemistry.…”

“…A similar tendency was also confirmed in the proton conductivities of ImH confined in Al-MOMs, CAU-11, MIL-53, MIL-53, and MIL-53-(Me) 2 . [103] As shown in Figure 17, less host-guest interactions between confined ImH and nanochannel exhibited higher proton conductivities.…”

“…AlO 6 polyhedra are shown in dark blue, carbon atoms in black, and nitrogen atoms in light blue. The potential hydrogen bonds are shown as dashed blue lines.Reproduced with permission [103]. Copyright 2016, Royal Society of Chemistry.…”

A Flexible and Porous Ferrocene‐Based Gallium MOF with MIL‐53 Architecture

“…Especially in the case of sterically demanding linker molecules or functional groups these "joints" are often involved. [38] The adsorption process of iodine and pyrazine affects the different torsion angles between the GaO 6 polyhedra (Θ 3 ) and the angle of the carboxylate groups to the cyclopentadienyl rings (Θ 1 and Θ 2 ) (for more information, see Figure S31 and Table S3). A combination of these two parts of the framework leads also to tilted ferrocene building units in the structure of the guest loaded MOFs (Figure 8, small inserts).…”

A Hierarchically Porous Carbazole‐Containing Polymer from [p‐(4‐N‐carbazole)‐C6H4SiO1.5]8 to Load Imidazole for Efficient Proton Conductivity over a Wide Temperature Range

“…At this point, Kitagawa and co‐workers are pioneers in encapsulating imidazole molecules into porous metal‐organic frameworks (MOFs) to target composite superprotonic conducting materials . Up to now, extensive research efforts have been devoted to incorporate the imidazole into MOFs, periodic mesoporous organosilicas (PMOs), covalent organic frameworks (COFs) and inorganic materials . Recently, hierarchically porous carbazole‐based polymers have garnered researcher's interest for the following reasons: 1) the cheap raw material; 2) excellent chemical and environmental stability; 3) the improvement of guest molecule accessibility and simultaneously promoting the mass transport through the matrix due to the hierarchical pores.…”