A New Member of the Metal‐Porphyrin Frameworks Family: Structure, Physicochemical Properties, Hydrogen and Carbon Dioxide Adsorption

Abstract A novel holmium‐based porous metal‐porphyrin framework, {(H3O+)[Ho(H2TPPS)]− ⋅ 4H2O}n (denoted as UPJS‐17), was synthesised by hydrothermal reaction. Structural analysis reveals, that UPJS‐17 has a three‐dimensional open framework. The framework is negatively charged and the negative charge is compensated by hydronium cation. The compound showed no N2 adsorption but the Ar, CO2 and H2. From the argon adsorption, the surface area of ~150 m2 g−1 was determined. Carbon dioxide adsorption was measured at various temperatures (0, 10, 20, 30 and 40 °C) and the compound showed the highest adsorption capacity (at 0 °C) of 7.0 wt % of CO2. From the carbon dioxide adsorption isotherms the isosteric heat of 56,5 kJ mol−1 was determined. Hydrogen adsorption was studied at −196 °C with hydrogen uptake of 2.1 wt % at 1 bar.


X-ray structure determination
The single-crystal X-ray diffraction data set was measured on a Nonius Kappa CCD diffractometer equipped with a Bruker APEX II detector.For UPJS-17 Cu/Kα (λ = 1.54178Å) at 288(2) K radiation was used.Data reduction was carried out by the diffractometer software.The phase problem was solved by direct methods and refined with full-matrix least-squares on F 2 using the Shelx-18 program suite. 31Hydrogen atoms were refined isotropically and all other atoms anisotropically.Hydrogen atoms residing on aromatic carbon atoms were included in an ideal position with the C−H bond fixed to 0.95 Å and Uiso(H) assigned to 1.2Ueq of the adjacent carbon atom.The contribution of guest molecules located in the pores was substracted by the SQUEEZE procedure in Platon. 32The structure figures were drawn using DIAMOND software. 33Crystal data for UPJS-17 is summarized in Tab.S1 in ESI.Crystal structures of UPJS-17 is deposited with CSD (2167706) and can be retrieved free of charge from https://www.ccdc.cam.ac.uk/structures.Deposition Number

Characterization
The elemental analysis was performed using an CHNOS Elemental Analyzer vario MICRO from Elementar Analysensysteme GmbH.
Powder X-ray diffraction (PXRD) experiments were done in reflection Bragg-Brentano geometry using a Bruker D2 Phaser diffractometer.Powder samples were loaded in metal frame PXRD experiments were done by 2θ continuous scan at 0.5° min -1 from 5° to 35° and diffracted photons were recorded using a SSD160 detector.The diffuse reflectance infrared Fourier transform (DRIFT) measurements were performed at the Nicolet Avatar FT-IR 6700 spectrometer, equipped with an electromagnetic source in the mid-infrared region (4000 -500 cm −1 ) and a DTGS detector.For each spectrum, 200 scans were accumulated with a resolution of 4 cm −1 .IR measurements were performed by the Praying Mantis in-situ cell under vacuum and the pure KBr was measured as a reference background.
The thermal behaviour was studied by thermogravimetry (TGA) combined with differential thermal analysis (DTA) in the temperature range 25-900 °C, with a heating rate of 6 °C min -1 using a STA Netzsch 409PC instrument.

Figure S2
The results of TG/DTA characterization for UPJS-17 sample.
Before all adsorption measurements of various gases (Ar, N2, CO2 and H2), samples were degassed at 150 °C for 16 hours under dynamic vacuum.The surface areas and pore volumes of the samples were measured by argon sorption at -186 °C (by nitrogen sorption at -196 °C) using a Quantachrome AUTOSORB-iQ-C automated gas sorption system.The total surface area was calculated via the Brunauer Emmett Teller (BET) equation and the micropore volume was obtained by means of the DFT (NLDFT kernel) method.Adsorption isotherms of carbon dioxide at various temperatures were measured using a Quantachrome AUTOSORB-iQ-C with a combined volumetric and dynamic sorption system.The hydrogen (99.999% purity) adsorption measurements were measured on the static manometric adsorption system, Autosorb iQ-XR developed by Quantachrome Instruments.The H2 isotherms were measured in the range of 0.5-101 kPa of absolute pressure.

Figure S1
Figure S1 Comparison of PXRD patterns of measured UPJS-17 (red curve), calculated UPJS-17 data from SXRD measurements (black curve) and sample after activation and adsorption measurements (blue curve).

Table S2
Gas storage capacities of compounds with UPJS acronym.