A Comparison of the H₂ Sorption Capacities of Isostructural Metal–Organic Frameworks With and Without Accessible Metal Sites: [{Zn₂(abtc)(dmf)₂}₃] and [{Cu₂(abtc)(dmf)₂}₃] versus [{Cu₂(abtc)}₃]

Abstract

The isostructural metal–organic frameworks [{Zn2(abtc)(dmf)2}3] (1 a), [{Cu2(abtc)(dmf)2}3] (2 a), and [{Cu2(abtc)}3] (2 b; H4abtc=1,1′-azobenzene-3,3′,5,5′-tetracarboxylic acid) have high sorption capacities for H2, N2, CO2, and CH4. Solid 2 b, which has accessible metal sites (AMSs), has a higher H2 adsorption capacity than 1 a or 2 a (see picture; T=77 K), neither of which have AMSs, because of its lower molecular weight and greater isosteric heat of H2 adsorption. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2008/z801488_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.