an amide - functionalized 
 metal organic framework ( mof ) material , 
 mfm-136 , shows a high co2 uptake of 12.6 mmol g1 at 20 bar and 298 k. mfm-136 is the first example of an acylamide 
 pyrimidyl isophthalate mof without open metal sites and , thus , provides 
 a unique platform to study guest binding , particularly the role of 
 free amides . 
 neutron diffraction reveals that , surprisingly , there 
 is no direct binding between the adsorbed co2/ch4 molecules and the pendant amide group in the pore . 
 this observation 
 has been confirmed unambiguously by inelastic neutron spectroscopy . 
 this suggests that introduction of functional groups solely may not 
 necessarily induce specific guest 
 host binding in porous materials , 
 but it is a combination of pore size , geometry , and functional group 
 that leads to enhanced gas adsorption properties .