Crystalline Inclusion of Wheel-and-Axle Diol Hosts Featuring Benzo[b]thiophene Units as a Lateral Construction Element

Abstract

By applying the 'wheel-and-axle' host concept and incorporating a previously developed heteroaromatic substitution strategy, a new type of diol hosts featuring two di(benzo [b]thien-2-yl)hydroxymethyl units attached to both ends of a central ethynylene (3) and 1,4-phenylene (4) moiety is reported. The syntheses of the host compounds are described and solvent inclusion formation via crystallization has extensively been studied showing a remarkable inclusion capability of the compounds. X-ray diffraction analysis of relevant crystal structures have been performed and comparatively discussed. Vapor sorption behavior of the compounds as solid receptor films coated on a quartz crystal microbalance considering a variety of solvent vapors has been scrutinized, indicating potential application as mass sensitive materials.3

Crystalline Inclusion Compounds of a Palladacyclic Tetraol Host Featuring o‐Carborane Units

“…Furthermore, decoration of the host with functional groups capable of hydrogen bonding often improves the inclusion properties. Wheel‐and‐axle molecular geometries (Figure ), first reported by Toda, correspond to this line of reasoning , . Such molecular geometries are produced by connecting two bulky propeller‐shaped groups by a long linker (for short linkers, they are known as the dumbbell[2a] type).…”

“…Wheel-and-axle molecular geometries (Figure 1), first reported by Toda,[4] correspond to this line of reasoning. [3,5] Such molecular geometries are produced by connecting two bulky propeller-shaped groups by a long linker (for short linkers, they are known as the dumbbell [2a] type). These types of compounds have been developed into a large family of purely organicbased hosts for lattice-inclusion compounds with variations in the end groups (wheels) and/or central linear building block (axle).…”

Structural studies on inclusion compounds and solvent sorption behavior of gradually elongated wheel-and-axle-type diol hosts featuring lateral benzo[b]thiophene units

“…This would mean that the hosts featuring an ethynylene unit attached to the hydroxyl substituted carbon atom (BTh1, 2, 4-6) are favored over hosts having an attached phenylene unit (BTh2, 1, 3); but also in this respect there is no corresponding trend justified by the data. Hence, the results once more [12,13,36] In further studies, we observed a preconditioning effect of the sorptive coating. This has been found working with host compound 6 showing high ratios of included EtOH both on solvent crystallization (1:4 stoichiometry) and vapor sorption (185 %) when 6 having been deposited from CHCl3 solution.…”

“…1) leads to a distinct enhancement of the crystalline inclusion formation with organic solvent molecules [13]. Following this line of thought, the question arises whether the intended homologues of BTh1 and BTh2, i.e.…”

“…As a result, the resonance frequency of the quartz crystal is shifted delivering information on the amount of the incorporated solvent [35]. To enable a sound comparison with previous data obtained from BTh1 and BTh2 [13], a series of different solvent vapors being in correspondence with a former selection of vapors [12,13] was used.…”