Inclusion in Microporous β-Bis(1,1,1-trifluoro-5,5-dimethyl-5- methoxyacetylacetonato)copper(II), an Organic Zeolite Mimic

Abstract

In this contribution, we show that the porous β-form of the title complex preserves its host lattice pore structure in the presence of more than 100 guests. Among the species that are able to promote the α-to-β transformation and that are capable of being included as guests are the gaseous and condensed hydrocarbons, their halo derivatives, alcohols, diols, aldehydes, ketones, ethers, esters, ethers of inorganic acids, acids, nitriles, and a variety of substituted aromatics. The empty β-form behaves like a microporous sponge, instantly absorbing significant quantities even of highly volatile compounds such as methane, ethane, and propane. The material demonstrates 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 increases from 142 °C (incongruent melting) to 163.5 °C (true melting) in the series from n-C5 to n-C16, while the guest-free α-form of the complex melts at 157 °C. The interaction of the complex with alcohols illustrates competing options between chemical bonding to copper and physical sorption into the microporous β-form. Methanol and ethanol coordinate to copper, thereby taking part in building, respectively, 2-D and 1-D polymers, whereas higher alcohols induce conversion to a 3-D β-form, stabilizing this porous modification by inclusion. From the observed stoichiometry and thermal stability, the host matrix is shown to be capable of molecular recognition of alcohols that have a shape and dimensions complementary to available pore geometry. Finally, the prospects for the rational design of new 3-D microporous polymers of bis-chelate building blocks are discussed.

Xe NMR lineshapes in channels of peptide molecular crystals

“…The dipeptide architectures built on hydrogen-bonding interactions present an example of a previously uncharacterized class of ''soft'' sorbents that have a micropore structure that is sensitive to the presence, concentration, and properties of the guest species (2,(37)(38)(39)(40). Only a few detailed investigations have been directed at understanding the sorption behavior of such materials (41)(42)(43)(44), and similar studies on the materials studied here likely will be quite helpful.…”

Hyperbranched Fluoropolymers and their Hybridization into Complex Amphiphilic Crosslinked Copolymer Networks

“…an order of magnitude faster from the composite networks, with the same dependence upon the wt.-% PEG as observed for the thermodynamic studies. Being different from the common guest-host systems, such as cyclodextrins [63] and zeolites, [64] amphiphilic crosslinked HBFP (I) /PEG networks demonstrated an unusual temperature-promoted release of guest molecules. It was clear that such a phenomenon was related with the compositional and morphological complexities of these amphiphilic HBFP (I) /PEG networks (vide supra), and further studies are underway to better understand the influences contributed from each parameter.…”

Crystal Structures and Melting Behaviors of 2D and 3D Anionic Coordination Polymers Containing Organometallic Ionic Liquid Components

“…Incongruent melting hasb een observed in silicate minerals, metal salts, and molecular compounds, [17] thoughvery few examples of incongruent melting of coordination polymers have been reported. [18] Microscope images depicting the meltingb ehaviors of 3-Rb and 3-K are shown in Figure 6b and Figure S5 Figure S6). When the mixture was cooled, parto ft he liquid phase underwent peritectic forma-tion, and subsequentc ycles reversibly switchedb etween melting and crystallization.…”