Inclusion in microporous beta-bis(1,1,1-trifluoro-5,5-dimethyl-5-methoxyacetylacetonato)copper(II), an organic zeolite mimic

In this contribution, we show that the porous beta-form of the title comple x preserves its host lattice pore structure in the presence of more than 10 0 guests. Among the species that are able to promote the alpha-to-beta tran sformation and that are capable of being included as guests are the gaseous and condensed hydrocarbons, their halo derivatives, alcohols, diols, aldeh ydes, ketones, ethers, esters, ethers of inorganic acids, acids, nitriles, and a variety of substituted aromatics. The empty beta-form behaves like a microporous sponge, instantly absorbing significant quantities even of high ly volatile compounds such as methane, ethane, and propane. The material de monstrates zeolite-like behavior, not only from the robustness of the empty pore structure, but also from its propensity for efficient adsorption and desorption. The thermal stability of inclusions with normal paraffins incre ases from 142 degrees C (incongruent melting) to 163.5 degrees C (true melt ing) in the series from n-C5 to n-C16, while the guest-free alpha-form of t he complex melts at 157 degrees C. The interaction of the complex with alco hols illustrates competing options between chemical bonding to copper and p hysical sorption into the microporous beta-form. Methanol and ethanol coord inate to copper, thereby taking part in building, respectively, 2-D and 1-D polymers, whereas higher alcohols induce conversion to a 3-D beta-form, st abilizing this porous modification by inclusion. From the observed stoichio metry and thermal stability, the host matrix is shown to be capable of mole cular recognition of alcohols that have a shape and dimensions complementar y to available pore geometry. Finally, the prospects for the rational desig n of new 3-D microporous polymers of bis-chelate building blocks are discus sed.