| Sumario: |
A new silver-triazolate metal-organic framework (MOF), {Ag 3[Ag5(μ3-3,5-tBu 2tz)6](BF4)2}n (2), has been prepared and structurally characterized. The CO2 sorption properties of this new MOF and previously reported isostructural analog {Ag 3[Ag5(μ3-3,5-Ph2tz) 6](NO3)2}n (1), were determined experimentally and probed theoretically by a density functional (DF) method. The structures of 1 and 2 are based on flexible Ag5tz 6-structural building units (SBUs), which allow the expansion/contraction of the structure, depending on either the steric requirements of the pendant groups - tBu, or Ph - of the SBUs, or the pressure of the gaseous sorbate. Both silver-triazolate MOFs sorb CO 2 preferentially to N2, O2, CH4 and H2. DF calculations show CO2 to be bound by van der Waals forces to the organic moieties of the porous framework. This work shows that van der Waals interactions of CO2 and the aromatic and aliphatic hydrocarbons of silver-triazolate MOFs are sufficient to achieve preferential sorption of CO2.
|