Polycyclic aromatic hydrocarbons as test probes to investigate the retention behavior of 1,3-alternate calix[4]arene silica-bonded stationary phases

Abstract

A series of polycyclic aromatic hydrocarbons (PAHs) of different size and shape has been used to characterize the chromatographic behavior of five calix[4]arene stationary phases in 1,3-alternate conformation synthesized in our laboratory. The selection of linear, four-ring nonlinear, and five-ring PAHs gave data on selectivity changes across range of the calix[4]arene columns. Retention of the 12 aromatic solutes has been evaluated at various methanol contents in the mobile phase (70-100% v/v) and column temperatures (20-45°C). The thermodynamic parameters underlying the retention mechanisms revealed that each of the five calix[4]arene columns exhibited variation in selectivity and retention of PAHs caused by enthalpy and entropy effects. The calixarene stationary phases substituted with electron-withdrawing groups exhibit enhanced selectivity toward PAHs in comparison to the rest of the investigated columns. The observed divergences are due to differences in solute-stationary phase interactions and originate in π-π and π-electron transfer specific to the analytes and the type of calix[4]arene functionalization at the upper rim, as well as steric and sorption phenomena.

Selected applications of calixarene derivatives

“…It is noteworthy that the applications of calixarenes are diversified; one may mention here the preparation of calixarene-based ionic liquids, 101,102 and formation of metal NPs, 103,104 today intensively studied. Although due to the large amount of works dealing with calixarenes, [105][106][107][108][109][110] in this review only selected examples are presented, one might hope that the recent reports here cited will help towards a better understanding of this interesting field of chemistry and related sciences.…”

Calixarene-engineered surfaces and separation science

“…Therefore, hydrogen-bonding and hydrophobic interactions are the two important interaction types which define the retention behavior of chemical species on calixarene-derived stationary phases. For more detailed information about stationary phase behavior of calixarenederived materials and host-guest interactions in chromatography, it is strongly suggested to refer valuable studies of Sokoließ et al [12,71].…”

Preparation and evaluation of a chiral HPLC stationary phase based on cone calix[4]arene functionalized at the upper rim with l‐alanine units

“…Interest in the use of calix[n]arene derivatives as stationary phases is increasing rapidly, because their derivatives can form inclusion complexes and hydrophobic, π – π interactions with solutes. For these reasons, some functionalized calix[n]arenes have been synthesized and their applications have been reported in a variety of chromatography fields, for example gas chromatography (Delahousse et al, ; Fan et al, ; Yu, Fang, Lin, Han, & Wu, ), capillary electrophoresis (Wang, Chen, Yuan, Huang, & Liu, ; Yang, Yu, Yu, & Chen, ; Zhou, Li, & Zeng, ), capillary electrokinetic chromatography (Hamilton, ) and liquid chromatography (Barc & Śliwka‐Kaszyńska, ; Deng et al, ; Erdemir & Yilmaz, ; Hu et al, ; Lu et al, ; Śliwka‐Kaszyńska & Ślebioda, ). Recently, we have introduced a stationary phase, based on calix[4]arene derivative for the separation of Fmoc‐protected amino acids (Zadmard, Tabar‐Heydar, & Imani, ).…”