High Ethene/Ethane Selectivity in 2,2'-Bipyridine-Based Silver(I) Complexes by Removal of Coordinated Solvent.

Following removal of coordinated CH³CN, the resulting complexes [AgI(2,2'-bipyridine)][BF4] (1) and [AgI(6,6'-dimethyl-2,2'-bipyridine)][OTf] (2) show ethene/ ethane sorption selectivities of 390 and 340, respectively, and corresponding ethene sorption capacities of 2.38 and 2.18 mmolg-1 when tested at an applied gas pressure of 90 kPa and a temperature of (20±1) °C. These ethene/ethane selectivities are 13 times higher than those reported for known solid sorbents for ethene/ethane separation. For 2, ethene sorption reached 90% of equilibrium capacity within 15 minutes, and this equilibrium capacity was maintained over the three sorption/desorption cycles tested. The rates of ethene sorption were also measured. To our knowledge, these are the first complexes, designed for olefin/paraffin separations, which have open silver(I) sites. The high selectivities arise from these open silver(I) sites and the relatively low molecular surface areas of the complexes. [ABSTRACT FROM AUTHOR]