Abstract
The rational design of metal-organic frameworks (MOFs) is highly important for the development of new proton conductors. Porphyrinylphosphonate-based MOFs, providing the directed tuning of physical and chemical properties of materials through the modification of a macrocycle, are potentially high-conducting systems. In this work the synthesis and characterization of novel anionic Zn-containing MOF based on palladium(ii) meso-tetrakis(3-(phosphonatophenyl))porphyrinate, IPCE-2Pd, are reported. Moreover, the proton-conductive properties and structures of two anionic Zn-containing MOFs based on previously described nickel(ii) and novel palladium(ii) porphyrinylphosphonates, IPCE-2M (M = Ni(ii) or Pd(ii)), are compared in details. The high proton conductivity of 1.0 × 10-2 S cm-1 at 75 °C and 95% relative humidity (RH) is revealed for IPCE-2Ni, while IPCE-2Pd exhibits higher hydrolytic and thermal stability of the material (up to 420 °C) simultaneously maintaining a comparable value of conductivity (8.11 × 10-3 S cm-1 at 95 °C and 95% RH). The nature of the porphyrin metal center is responsible for the features of crystal structure of materials, obtained under identical reaction conditions. The structures of IPCE-2Pd and its dehydrated derivative IPCE-2Pd-HT are determined from the synchrotron powder diffraction data. The presence of phosphonic groups in compared materials IPCE-2M affords a high concentration of proton carriers that together with the sorption of water molecules leads to a high proton conductivity.
| Original language | English |
|---|---|
| Pages (from-to) | 6549-6560 |
| Number of pages | 12 |
| Journal | Dalton Transactions |
| Volume | 50 |
| Issue number | 19 |
| DOIs | |
| Publication status | Published - 21 May 2021 |
| Externally published | Yes |
Funding
The authors thank the RFBR grant (project No. 18-29-04036 mk) for financial support. We are grateful to Prof. Andrey A. Shiryaev for the assistance with VT-PXRD measurements, Daniil A. Kozlov (MSU) for SEM experiments and Andrei V. Perevoshchikov (MSU) for TGA experiments. The synthesis of precursors was supported by the Ministry of Science and Higher Education of the Russian Federation. MALDI TOF MS, NMR, IR, XPS, X-Ray and PXRD diffraction measurements along with the proton conductivity experiments were performed at the CKP FMI of the Frumkin Institute of Physical Chemistry and Electrochemistry, RAS, and at the CKP FMI of the Kurnakov Institute of General and Inorganic Chemistry, RAS. An analysis of the porous structure was carried out at the Shared Facility Centre of the Nikolaev Institute of Inorganic Chemistry, Siberian Branch, RAS. The authors acknowledge partial support from the User Facilities Center of Moscow State University. The authors thank the ESRF for providing access to the ID22 station, experiment MA-4527. The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript.
All Science Journal Classification (ASJC) codes
- Inorganic Chemistry