Urea-Derivatized p-tert-Butylcalix[4]arenes: Neutral Ligands for Selective Anion Complexation

Separation of Aromatic Isomers by Capillary Gas Chromatography with Two Calix[4]arene Polysiloxane Stationary Phases

“…Because of its basket-shaped cavity, it can form complexes with neutral molecules 1 and ions. [2][3][4] There have been many papers on synthesis of calixarene [5][6][7] , modification of its upper 8 and lower rims 9 , and applications, such as using them as accelerators for instant adhesives 10 , stationary phases for chromatography, ion selective electrodes and field effect transistors 11 and ion scavengers for electronic devices 12 , and to purify fullerenes. 13 Our group has worked on stationary phases containing crown ethers in gas chromatography for many years.…”

Synthesis and Selective Recognition of Dihydrogen Phosphate by Urea-Anthraquinone

“…3 Neutral ferrocene receptors, [4][5][6][7] thiouronium receptors, 8 neutral bisthiourea or bisurea hosts, [9][10][11][12] and porphyrin receptors 13 were investigated for selective recognition of H 2 PO 4 − anion. A selective complexation of Cl − , Br − or I − can be achieved by the neutral urea receptors derived from the lower rim of calix [4]arene, 14 and three urea groups at the lower rim of calix [6]arene are well suited for complexation of tricarboxylate. 15 The urea moiety is a powerful donor of hydrogen bond as recently shown in the complexation of dicarboxylate anion.…”

Identification and Recovery of an Asymmetric Calix[4]arene Tetranitrile Derivative using Liquid Chromatography and Mass Spectrometry

“…However, we found that due to (a) the high degree of substitution, (b) increasing difficulty to deprotonate successive phenol hydrogens and (c) the sterically hindered nature of target compounds, yields obtained were very small or the reactions were unsuccessful. Analogously, the synthesis of 3, as seen in Scheme 1, did not proceed as readily as that of 4 8 . This prompted the use of more advanced work up tools.…”