title: Flexible and hydrophobic Zn-based metal-organic framework.
abstract: A zinc-based metal-organic framework Zn(2)(adb)(2)(dabco)·4.5 DMF (K) (DUT-30(Zn), DUT = Dresden University of Technology, adb = 9,10-anthracene dibenzoate, dabco =1,4-diazabicyclo[2.2.2]octane, DMF = N,N-dimethylformamide) was synthesized using a solvothermal route. This MOF exhibits six crystallographic guest dependent phases. Two of them were characterized via single crystal X-ray analysis. The as-synthesized phase K crystallizes in the orthorhombic space group Fmmm, with a = 9.6349(9), b = 26.235(3), and c = 28.821(4) Å and consists of two interpenetrated pillar-layer networks with pcu topology. When the substance loses 0.5 DMF molecules per formula unit, a phase transition from the kinetic phase K to a thermodynamic phase T occurs. Zn(2)(adb)(2)(dabco)·4 DMF (T) crystallizes in the tetragonal space group I4/mmm, with a = 19.5316(8) and c = 9.6779(3) Å. During the evacuation the DUT-30(Zn) undergoes again the structural transformation to A. The activated compound A shows the gate pressure effect in the low pressure region of nitrogen physisorption isotherm and has a BET surface area of 960 m(2 )g(-1) and a specific pore volume of 0.43 cm(3) g(-1). Furthermore, DUT-30(Zn) exhibits a hydrogen storage capacity of 1.12 wt % at 1 bar, a CO(2) uptake of 200 cm(3) g(-1) at -78 °C and 0.9 bar, and a n-butane uptake of 3.0 mmol·g(-1) at 20 °C. The N(2) adsorption process was monitored in situ via X-ray powder diffraction using synchrotron radiation. A low temperature induced transformation of phase A to phase V could be observed if the compound was cooled under vacuum to -196 °C. A further crystalline phase N could be identified if the framework was filled with nitrogen at -196 °C. Additionally, the treatment of activated phase A with water leads to the new phase W.
authors.affiliation: Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, D-01069 Dresden, Germany.
authors.forename: Ines Maria
authors.initials: IM
authors.lastname: Hauptvogel
authors.forename: Ralf
authors.initials: R
authors.lastname: Biedermann
authors.forename: Nicole
authors.initials: N
authors.lastname: Klein
authors.forename: Irena
authors.initials: I
authors.lastname: Senkovska
authors.forename: Amandine
authors.initials: A
authors.lastname: Cadiau
authors.forename: Dirk
authors.initials: D
authors.lastname: Wallacher
authors.forename: Ralf
authors.initials: R
authors.lastname: Feyerherm
authors.forename: Stefan
authors.initials: S
authors.lastname: Kaskel