Selective, adsorbate-induced spin state changes in transition metal-based metal-organic frameworks
An adsorbate-selective metal organic framework includes a transition metal; and a plurality of organic molecules coordinated to the transition metal so as to preserve open coordination sites for selectively adsorbing molecules that have low-lying π* orbitals. The transition metal has a lowest energy spin state in the presence of the selectively adsorbed molecules that are strongly bonding to the transition metal through π-donating interactions which is different than the lowest energy spin state in the absence of these adsorbed molecules. The transition metal has also a lowest energy spin state in the presence of non-selected molecules that are weakly bonding to the transition metal through σ- and/or π-accepting and/or donating interactions.