English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Crystal engineering comprises an understanding of intermolecular interactions that govern crystal packing [1]. Unfortunately, most of the supramolecular networks based on these non-covalent interactions lack the necessary stability required for many potential applications. The ability to create permanent pores in supramolecular solids is considered as one of the biggest challenges in crystal engineering [2]. Usually, formation of a porous solid requires that the network sustaining interactions are of sufficient strength to pay the energetic penalty for existence of the pores themselves. We report herein the synthesis and crystal structures of two robust isostructural supramolecular porous compounds of Cu(II) and adenine with the formula [Cu2(adenine)4Cl2]Cl2.nCH3OH (1) and [Cu2(adenine)4Br2]Br2.nCH3OH (2). They have been obtained using methanol as solvent to assure the direct hydrogen bonding interaction between the adenine ligands, that otherwise would be disrupted by the strong capability of water to mediate such interactions. A handful of covalent 2D and 3D coordination compounds have been reported exploiting the ability of the nucleobases to act as polydentate bridging ligands, as far as we are aware, these compounds represents the first examples of a robust porous 3D architecture based on adeninecontaining complexes in which the self-assembling of the structural units is only driven by non-covalent interactions and shows a high thermal stability. The crystal structure of 1 consists of windmill shaped dimeric complex cations, [Cu2(μ-adenine)4Cl2], and chloride counterions. The four bridging adenine molecules are linked to copper(II) ions through its N3 and N9 nitrogen atoms with chlorido ligands in the apical positions providing an elongated square pyramidal coordination environment to the metal centers. The supramolecular structure involves the direct interaction between the Watson-Crick edges of adjacent adenines to give rise to a 3D overall supramolecular structure containing very large channels with a diameter of ~9 Å, that represents 28% of the total volume of the unit cell (Figure 1). The chloride counterions, not being placed inside the channels, contribute to robustness of the crystal structure acting as acceptors from two hydrogen bonds established with the N7 donor positions of two adenine molecules. The crystal structure remains stable up to 200 oC as checked by TG and XRPD measurements.

Porous supramolecular compounds based on paddle-wheel shaped copper(II) adenine entities