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Rotating pyrazine rings put a kink in Xe isotherms
SIFSIX-3-Fe takes up more Xe than Kr because its pores match Xe, while an inflection in SIFSIX-3-Ni’s Xe isotherm is attributed to pyrazine rings ordering from disordered to aligned rotations.
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What MOF platform was studied?
Pillared square grids SIFSIX-3-M, [M(pyz)2SiF6] with M = Fe or Ni.
Source: Effect of ring rotation upon gas adsorption in SIFSIX-3-M (M = Fe, Ni) pillared square grid networks · DOI · quote verified
What pore diameters do SIFSIX-3-M nets have?
About 3.5–3.8 Å, commensurate with Xe.
Source: Effect of ring rotation upon gas adsorption in SIFSIX-3-M (M = Fe, Ni) pillared square grid networks · DOI · quote verified
What Xe and Kr uptakes did SIFSIX-3-Fe show at 1 atm, 298 K?
54.9 cm3 STP g−1 Xe versus 30.8 cm3 STP g−1 Kr.
Source: Effect of ring rotation upon gas adsorption in SIFSIX-3-M (M = Fe, Ni) pillared square grid networks · DOI · quote verified
What were the corresponding Ni-analogue uptakes?
56.2 cm3 STP g−1 Xe and 12.6 cm3 STP g−1 Kr.
Source: Effect of ring rotation upon gas adsorption in SIFSIX-3-M (M = Fe, Ni) pillared square grid networks · DOI · quote verified
What infinite-dilution Xe Qst was found for SIFSIX-3-Fe?
27.4 kJ mol−1.
Source: Effect of ring rotation upon gas adsorption in SIFSIX-3-M (M = Fe, Ni) pillared square grid networks · DOI · quote verified
How does Ni Qst at low coverage compare?
18.9 kJ mol−1, lower than the Fe analogue.
Source: Effect of ring rotation upon gas adsorption in SIFSIX-3-M (M = Fe, Ni) pillared square grid networks · DOI · quote verified
To what is the Xe isotherm inflection in SIFSIX-3-Ni attributed?
A disordered-to-ordered transition of pyrazine rotational configurations, not breathing or guest–guest effects.
Source: Effect of ring rotation upon gas adsorption in SIFSIX-3-M (M = Fe, Ni) pillared square grid networks · DOI · quote verified
How many IN/OUT states can one cage theoretically adopt?
2^8 = 256 if each of eight pyrazines is IN or OUT.
Source: Effect of ring rotation upon gas adsorption in SIFSIX-3-M (M = Fe, Ni) pillared square grid networks · DOI · quote verified
How was SIFSIX-3-Fe made?
Solvothermal FeSiF6·6H2O (1 mmol) + pyrazine (2 mmol) in 20 mL methanol at 85 °C.
Source: Effect of ring rotation upon gas adsorption in SIFSIX-3-M (M = Fe, Ni) pillared square grid networks · DOI · quote verified
What BET area and pore size were reported for SIFSIX-3-Ni?
368 m2 g−1 and 3.66 Å, similar to Fe.
Source: Effect of ring rotation upon gas adsorption in SIFSIX-3-M (M = Fe, Ni) pillared square grid networks · DOI · quote verified
Low-pressure Xe uptake on SIFSIX-3-Fe at 0.1 bar?
30 cm3 STP g−1, indicating high Xe affinity.
Source: Effect of ring rotation upon gas adsorption in SIFSIX-3-M (M = Fe, Ni) pillared square grid networks · DOI · quote verified