Engineering void space in organic van der Waals crystals: calixarenes lead the way

Abstract

Seemingly non-porous organic solids have the ability for guest transport and have also been shown to absorb gases, including hydrogen, methane and acetylene, to varied extents. These materials also show potential for gas separation technology, display remarkable water transport through hydrophobic crystals, and clearly show that molecules within crystals are capable of cooperating with guests as they move through non-porous environments. This work is presented within a broader topic which also encompasses crystal engineering and (microporous) metal-organic frameworks (MOF's).

Induced Sensitivity and Selectivity in Thin‐Film Transistor Sensors via Calixarene Layers

“…The tunable nature of the container cavity serves to trap desired molecular shapes and functionalities with typically high selectivity. [19] The burgeoning interest in host-guest materials has given rise to exceptionally complex single- [20] and multicomponent [21] self-assembled structures, and such materials have been incorporated into sensors based on fluorescence, [22] surface acoustic wave (SAW), [23] and quartz crystal microbalance (QCM) [24] and polymer-coated chemiresistors. [25] In this article, we report the use of ultra-thin films of container molecules as sensory layers on an existing OTFT, resulting in both enhanced sensitivity as well as shape discrimination between vapors of small-molecule analytes.…”

Guest induced transformations of assembled pyridyl bis-urea macrocycles

“…1 Recent examples indicate that a permanent pore or channel is not necessarily a requirement for the absorption of gases. 2 Dynamic structural changes in coordination polymers induced new channels into which guest molecules were incorporated. 3 Atwood et al recently demonstrated that non-porous organic solids could expand by gas induced transformations.…”

Trimeric and hexameric calixarene-based capsules

“…It should be pointed out that the chemistry of dimeric capsules is better known than that of capsules of higher multiplicities, this fact having its reflection in number of reports that have appeared. [67][68][69][70] The above review, albeit presenting only chosen examples of trimeric and hexameric capsules highlights to some extent their formation and properties which are promising for their applications.…”