Structural transformation and high pressure methane adsorption of Co2(1,4-bdc)2dabco

A cobalt based metal-organic framework [Co2(1,4-bdc)2(dabco)] · 4DMF · H2O 1 (1,4-bdc = 1,4-benzenedicarboxylate, dabco = 1,4-diazabicyclo[2.2.2]octane, DMF = N,N-dimethylformamide) was synthesized using a solvothermal route. The crystals of 1 remain crystalline after solvent molecule removal. A reversible structure change between 1 and the guest-free structure [Co2(1,4-bdc)2(dabco)] 2 was characterized by single crystal X-ray analysis. Compound 1 crystallizes in the space group I4/mcm (No. 140), with a = 15.085(2), c = 18.906(4) Å, and metal-organic framework 2 in the space group P4/mmm (No. 123), with a = 10.963(4), c = 9.466(3) Å. The compound 2 has a specific micropore volume of 0.82 cm3 g−1, a hydrogen storage capacity of 2.27 wt.% at −196 °C and 1 bar, and an excess methane adsorption of 14.0 wt.% at 30 °C and 75 bar.