title: Reversible and selective O2 chemisorption in a porous metal-organic host material.
abstract: The metal-organic host material [{Co(III)(2)(bpbp)(O(2))}(2)bdc](PF(6))(4) (1·2O(2); bpbp(-) = 2,6-bis(N,N-bis(2-pyridylmethyl)aminomethyl)-4-tert-butylphenolato; bdc(2-) = 1,4-benzenedicarboxylato) displays reversible chemisorptive desorption and resorption of dioxygen through conversion to the deoxygenated Co(II) form [{Co(II)(2)(bpbp)}(2)bdc](PF(6))(4) (1). Single crystal X-ray diffraction analysis indicates that the host lattice 1·2O(2), achieved through desorption of included water guests from the as-synthesized phase 1·2O(2)·3H(2)O, consists of an ionic lattice containing discrete tetranuclear complexes, between which lie void regions that allow the migration of dioxygen and other guests. Powder X-ray diffraction analyses indicate that the host material retains crystallinity through the dioxygen desorption/chemisorption processes. Dioxygen chemisorption measurements on 1 show near-stoichiometric uptake of dioxygen at 5 mbar and 25 °C, and this capacity is largely retained at temperatures above 100 °C. Gas adsorption isotherms of major atmospheric gases on both 1 and 1·2O(2) indicate the potential suitability of this material for air separation, with a O(2)/N(2) selectivity factor of 38 at 1 atm. Comparison of oxygen binding in solution and in the solid state indicates a dramatic increase in binding affinity to the complex when it is incorporated in a porous solid.
authors.affiliation: School of Chemistry, The University of Sydney, NSW 2006, Australia.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Southon
authors.forename: David J
authors.initials: DJ
authors.lastname: Price
authors.forename: Pia K
authors.initials: PK
authors.lastname: Nielsen
authors.forename: Christine J
authors.initials: CJ
authors.lastname: McKenzie
authors.forename: Cameron J
authors.initials: CJ
authors.lastname: Kepert
mesh_terms: D000327:Adsorption; D000693:Anaerobiosis; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D016062:Porosity; D011312:Pressure; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D009942:Organometallic Compounds; D010100:Oxygen