Development of Porous Crystalline Materials for Selective Binding of O2 from Air

Porous materials that take advantage of different chemisorptive behaviors of O2 and N2 could be an effective alternative to approaches based on physisorption for this important separation. Recently, the tetra-nuclear cobalt complex [(Co­(III)2(bpbp)­O2)2bdc]­(PF6)4 (CSD code: GAMVIB; bpbp– = 2,6-bis­(N,N-bis­(2-pyridylmethyl)­aminomethyl)-4-tert-butylphenolato; bdc2– = 1,4-benzenedicarboxylato) was shown to have potential for O2/N2 separations based on this concept. This observation raises the question of what other known materials have similar properties. In this study, we combine structure screening with a high-throughput periodic density functional theory (DFT) workflow to investigate O2 and N2 adsorption in materials from validated crystal structure databases (e.g., CoRE-MOF database and CSD database). These calculations identify multiple materials that have similar di-Co clusters to GAMVIB that are predicted to selectively bind O2 over N2, and suggest design rules that can be used to tune the O2 and N2 affinities in materials of this kind.