Facile separation of cyclic aliphatic and aromatic vapors using crystalline thiacalixarene assemblies with preorganized channels.

Conventional distillation methods cannot separate compounds with similar boiling points, molecular sizes, and volumes, such as cyclohexane and benzene or methylcyclohexane and toluene, effectively. The corresponding cyclic aliphatic and aromatic hydrocarbons cannot be separated effectively using the same type of sorption material. We report that crystalline thiacalixarene assemblies featuring preorganized channel-like adsorption sites are capable of both separations.

Selective separation of branched alkane vapor by thiacalixarene supramolecular crystals having shape-recognition properties.

Activated crystals of a supramolecular assembly of bromothiacalix[4]arene propyl ether with preorganized channel-like voids can selectively and effectively adsorb isooctane vapor from a vapor mixture of isooctane and n-heptane.

Crystal structure of a supra-molecular lithium complex of p-tert-butyl-calix[4]arene.

Crystals of a supra-molecular lithium complex with a calix[4]arene derivative, namely tetra-methano-llithium 5,11,17,23-tetra-tert-butyl-25,26,27-trihy-droxy-28-oxidocalix[4]arene methanol monosolvate, [Li(CH3OH)4](C44H55O4)·CH3OH or [Li(CH3OH)4]+·(calix[4]arene-)]·CH3OH (where calix[4]arene- represents a mono-anion species because of deprotonation of one H atom of the calixarene hy-droxy groups), were obtained from p-tert-butyl-calix[4]arene reacted with LiH in tetra-hydro-furan, followed by recrystallization from methanol. The asymmetric unit comprises one mono-anionic calixarene mol-ecule, one Li+ cation coordinated to four methanol mol-ecules, and one methanol mol-ecule included in the calixarene cavity. The calixarene mol-ecule maintains a cone conformation by intra-molecular hydrogen bonding between one phenoxide (-O-) and three pendent calixarene hy-droxy groups (-OH). The coordinated methanol mol-ecules around the metal cation play a significant role in forming the supra-molecular assembly. The crystal structure of this assembly is stabilized by three sets of inter-molecular inter-actions: (i) hydrogen bonds involving the -OH and -O- moieties of the calixarene mol-ecules, the -OH groups of the coordinated methanol mol-ecules, and the -OH group of the methanol mol-ecule included in the calixarene cavity; (ii) C-H⋯π inter-actions between the calixarene mol-ecules and/or the coordinated methanol mol-ecules; (iii) O-H⋯π inter-actions between the calixarene mol-ecule and the included methanol mol-ecule.

Double stranded DNA discrimination by di-pyrene modified gamma-cyclodextrin.

Neutral fluorescent active di-pyrene modified gamma-cyclodextrin (1) was synthesized in order to discriminate with single and double strand DNA (ssDNA and dsDNA, respectively) with high selectivity. The binding and selectivity of 1 for dsDNA was indicated by increase of the fluorescent intensity in an addition of dsDNA. On the other hand, an increase of fluorescent intensity of 1 was not recognized in an addition of ssDNA.