Q2. What is the coordination environment around the Cu2+ center?
The coordination environment around the Cu2+ center is octahedralcoordinated to dhbpc and bpy and the dihedral angle of benzene rings in dhbpc is 34.0.
Q3. How did the authors prepare the interdigitated framework?
To shift the gate-opening pressure of CO2 above 0.1 MPa and avoid CH4 adsorption in the pressure range of zero to 1 MPa, the authors prepared an interdigitated framework by employing 20the 4,4'-dihydroxybiphenyl-3-carboxylic acid (H3dhbpc) as a ligand.
Q4. How much uptake of CO2 was observed at 2 steps?
Although 1 represented single gate-opening type adsorption at 2.2 kPa, 2 gave gradual uptake 75until P = 2.2 kPa and second jump was observed.
Q5. How did the structure of the dhbpc change?
The structural 15transformation had low activation energy and afforded thefavorable adsorptions of CO2 and CH4 at low pressure at 273 K.
Q6. What is the effect of local reorientation on the stacking of 2D layers?
The local reorientation affects the stacking of 2D layers and thenetworks are densely packed resulting the guest accessible void volume of 2.1%.19
Q7. How did the authors measure the separation ability of CH4 from CO2?
The authors dosedmixture gas (CH4:CO2 = 1:1(vol)) for 2 under the condition of total pressure 0.1 MPa and 273 K then hold three hours to 15wait the equilibrium co-adsorption process and detected theadsorbed gas species by gas chromatography.
Q8. What is the way to measure the separation ability of CO2 from CO2?
Take the single adsorption isotherms of CO2 and CH4 into consideration, the compound 2 is expected to show high separation ability in 25wide range of pressure, especially above 0.1 MPa.
Q9. What is the difference between the two ligands?
In conclusion, the authors demonstrated that the minor modificationof the ligand moiety in the layer framework causes aremarkable change in the gas adsorption properties, which is 40relevant for appropriate gas separation condition with lowenergy consumption process.
Q10. What is the structure of the H3dhbpc?
25The H3dhbpc was synthesized according to the literature method.21 Slow diffusion of Cu(NO3)2∙3H2O and H3dhbpc with bpy in acetone and water solution formed green singlecrystal [Cu(dhbpc)2(4,4’-bpy)]