| Abstract | The microporous polymorph of the title compound has been prepared as a crystalline product by slow removal of the guest from the inclusion compound with methylene chloride, [CuL2]*2/3(CH2Cl2) (L is 1,1,1-trifluoro-5,5-dimethyl-5-methoxyacetylacetonate, {CF3COCHCOC(CH3)2OCH3}-). Collapse of the crystals of the polymorph into the thermodynamically stable form has been studied by visual observation and DSC calorimetry, the product exhibiting much higher kinetic stability than the polycrystalline samples prepared so far. The crystal structure of the polymorph was determined by single-crystal XRD methods both at 293 and 173 K. The polymorph retains the same 3D polymeric coordination framework as found previously in inclusion compounds of the complex. The structures of the and polymorphs are compared and the variation of the matrix in a series of compounds was analyzed. The framework described in this work seems to be the most flexible of all coordination polymers known so far, preserving its microporous structure upon guest exchange or removal; the complete range of change in molar volume observed for the matrix is 8.6%. |
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