title: Redox chemistry and metal-insulator transitions intertwined in a nano-porous material.
abstract: Metal-organic frameworks are nano-porous adsorbents of relevance to gas separation and catalysis, and separation of oxygen from air is essential to diverse industrial applications. The ferrous salt of 2,5-dihydroxy-terephthalic acid, a metal-organic framework of the MOF74 family, can selectively adsorb oxygen in a manner that defies the classical picture: adsorption sites either do or do not share electrons over a long range. Here we propose, and then justify phenomenologically and computationally, a mechanism. Charge-transfer-mediated adsorption of electron acceptor oxygen molecules in the metal-organic framework, which is a quasi-one-dimensional electron-donor semiconductor, drives and is driven by quasi-one-dimensional metal-insulator-metal transitions that localize or delocalize the quasi-one-dimensional electrons. This mechanism agrees with the empirical evidence, and predicts a class of nano-porous semiconductors or metals and potential adsorbents and catalysts in which chemistry and metal-insulator-metal transitions intertwine.
authors.affiliation: College of Chemistry, University of California, Berkeley, California 94720-1460, USA.
authors.forename: Sergey N
authors.initials: SN
authors.lastname: Maximoff
authors.affiliation: 1] College of Chemistry, University of California, Berkeley, California 94720-1460, USA [2] Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460, USA.
authors.forename: Berend
authors.initials: B
authors.lastname: Smit