Diffusion of water in a nonporous hydrophobic crystal

Burrowing water: The apohost phase of a substituted hydrophobic calixarene, grown by sublimation, forms lattice voids but not channels. Exposure of the crystals to liquid water results in a single-crystal-to-single-crystal phase transformation during which water molecules become embedded in the lattice voids (see picture); thus the classical view of diffusion might not be appropriate at the atomic scale. (Chemical Equation Presented) © 2005 Wiley-VCH Verlag GmbH & Co. KGaA.</p

Engineering void space in organic van der waals crystals: Calixarenes lead the way

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). © 2007 The Royal Society of Chemistry.</p

Polymorphism of pure p-tert-butylcalix[4]arene: Subtle thermally-induced modifications

A low-density polymorph of the well-known host compound p-tert-butylcalix[4]arene undergoes subtle structural changes when heated and cooled. © 2004 Royal Society of Chemistry.</p

Crystal engineering of nonporous organic solids for methane sorption

The low density polymorph of the well-known host p-tert-butylcalix[4]arene absorbs more methane than p-tert-pentyl-calix[4]arene at room temperature and 1 atm pressure, but the order of absorption is reversed at 38 atm with p-tert-pentylcalix[4]arene absorbing more. © The Royal Society of Chemistry 2005.</p

A crystalline organic substrate absorbs methane under STP conditions

A well-known host compound readily absorbs methane at room temperature and pressures of one atmosphere and lower.</p

Diffusion of vaporous guests into a seemingly non-porous organic crystal

The tetragonal apohost phase of p-tert-butyltetramethoxythiacalix[4]arene absorbs hydrochloric acid and iodine. These guest molecules occupy different sites in the solid-state structure – either within the small intrinsic voids of the macrocycle or within the interstitial spaces between the host molecules. This study illustrates the dynamic deformation of the host, providing strong mechanistic insight into the diffusion of guests into this seemingly non-porous material. 2014 © The Royal Society of Chemistry.</p

Acetylene absorption and binding in a nonporous crystal lattice

Unusual storage: An organic nonporous material, p-tert-butylcalix[4]arene, sorbs acetylene with high storage density under ambient conditions. It is presumed that gas molecules diffuse through the seemingly nonporous lattice without disrupting the arrangement of the host molecules (see picture; red O, blue C, gray H, yellow void space). (Figure Presented) © 2006 Wiley-VCH Verlag GmbH & Co. KGaA.</p

Organic crystals absorb hydrogen gas under mild conditions

We have studied the hydrogen sorption on three well-known organic hosts that possess vacant lattice voids large enough to accommodate H2 molecules. © The Royal Society of Chemistry 2005.</p