Finding a New Crystalline Sponge from a Crystallographic Database

Abstract

Empirical searching conditions were adopted to identify suitable candidates from the Cambridge Structural Database (CSD) for crystalline sponge hosts for X-ray crystallographic analysis of incoming guest compounds. After optimization of the solvent and soaking conditions, one of the candidates was used as a crystalline sponge for the structure determination of an aromatic guest.Since the appearance of the crystalline sponge method, [1]

What makes a crystal structure report valid?

“…Contrarily, the need to use constraints and restraints on the geometry of the molecule of interest may severely lower its scientific value, in particular when the interest lies in geometrical details such as distances, angles and intermolecular interactions or the positive identification of unknown atom types from the geometry and peak density. The structure reported in [17] might be (made) valid and have a value in demonstrating the sponge technique but of very limited value for detailed geometry information.…”

“…The monoclinic unit cell includes four of those channels covering $40% of the unit cell volume. Fujita et al [17] published as an example the sponge structure of 1-acetonaphthone soaked into this new 3D MOF along with the associated refinement and reflection data (CCDC deposition code 1511768). This allows us to illustrate its structure validation, to investigate the quality of the MOF framework and to evaluate the quality of the sought for molecular geometry of the embedded 1-acetonaphthone guest molecule.…”

“…The authors of [17] The guest molecule geometry in channel A was refined without restraints. The CAC bond distances in the naphthyl moiety deviate by À0.10 to 0.06 Å from the corresponding distances in the quality structure [13] depicted in Fig.…”

“…The bond distances and displacement parameters for the guest molecule in the B channel are heavily constrained to be similar and similar as in Ref. [17].…”

Crystallographic investigation into the self-assembly, guest binding, and flexibility of urea functionalised metal-organic frameworks

“…This approach has been successfully used to examine guest binding in coordination cages (60), but reported structures of MOFs with bound CS 2 remain relatively rare (61)(62)(63)(64)(65)(66)(67). As with the recently published study (29), [Zn 4 O(L) 3 (DMF) 2 ] n was found to be relatively unstable to solvent removal, but CS 2 is a volatile nonpolar solvent that may allow for efficient activation, and samples maintained crystallinity on solvent exchange from DMF to CS 2 .…”