Enclathration of Picoline Isomers by (rac)-TADDOLs: Structures, Selectivity, and Thermal Analysis

Abstract

In this investigation, we studied the preferences of three α,α,α′,α′-tetraphenyl-l,3-dioxolane-4,5-dimethanol (TAD-DOL)-derived host compounds toward the isomers of methylpyridines (picolines). Ten novel inclusion compounds were synthesized, and their structural and thermal properties were further characterized. Binary competition experiments were performed, and all three hosts discriminate between the picoline isomer guests. Interestingly, all three hosts display different preferences toward the isomers, and these results were rationalized by their resulting crystal structures and packing analysis and correlated to their differential scanning calorimetry (DSC) results. DSC results showed a correlation between the thermal stability of an inclusion compound and the preference of the host toward a given isomer.

Selectivity considerations of host compound trans-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid when presented with pyridine and picoline mixtures: charge-assisted versus classical hydrogen bonding

“…14 Here, we have investigated the host and selectivity behaviour a roof-shaped compound, trans-9,10-dihydro-9,10ethanoanthracene-11,12-dicarboxylic acid (H1), when presented with various mixtures of PYR, 2MP, 3MP and 4MP. Nassimbeni et al performed similar studies in the MPs but employed racemic TADDOLs as the host compounds, where the aromatic para position was modified from bearing a hydrogen atom to fluorine and methyl derivatives: 20 they found that each of these three derivatives possessed different preferences for the picolines. In the present work, the synthesis of H1 was inspired by Edwin Weber 21 and has long since been demonstrated to have the ability to behave as a host compound.…”

Adsorptive separation of picoline isomers by adaptive calix[3]acridan crystals

“…Although co-crystallization could be energy efficient for the separation of picoline isomers, this process is time-consuming during slow evaporation and the formation of the crystalline complexes. [2][3][4][5][6][7] Adsorptive separation is an alternative strategy. In particular, macrocycle-based nonporous adaptive crystals (NACs) have emerged as excellent candidates for adsorption and separation due to their advantages of facile preparation, low cost, good thermal stability and high recyclability.…”

“…8,9 In this respect, pillararenes are in the vanguard, and have been shown to be effective for the separation and purification of various industrially important hydrocarbons. [10][11][12][13][14][15][16][17][18][19][20][21] Apart from pillararenes, several sporadic examples of macrocyclic NACs have also been developed, such as cucurbit [6]uril, 22 hybrid [3]arene, 23 geminiarene, 24 biphen [3]arene, 25 tiara [5]arene, 26 naphthotube, 27 trianglimine, 28,29 calix[4]pyrrole 30 and rhombicarene 31 However, most of these macrocycles suffer from multistep synthesis procedures or low product yields, which is a disadvantage to the practical application of NAC materials. Hence, it is important to exploit new-type macrocyclic NACs that are of easy synthetic availability and superior separation performance.…”