Calixarenes. 4. The synthesis, characterization, and properties of the calixarenes from p-tert-butylphenol

Interaction of para-tert-butylcalix[6]arene molecules in Langmuir films with cadmium ions and their effects on molecular conformation and surface potential

“…According to eqn (2) and (3), if the dipole moment contributions were not changed (since only the subphase was altered), the surface potential was expected to increase with incorporation of Cd 2+ ions, since the (negative) double-layer potential would be reduced. However, the data in Fig.…”

“…[1][2][3] Due to their cone-like structure [1][2][3] and the presence of phenol oxygen donor atoms, [1][2][3][4] calixarenes may be complexed with metal ions or incorporate charged and neutral molecules. [1][2][3][4][5] With such properties, calixarenes have been used in detecting metallic ions, such as alkaline [6][7][8] and alkaline earth [8][9][10] metals, cadmium, [10][11][12] copper, 7,13,14 and for incorporating neutral molecules, [15][16][17][18][19][20] including dopamine, 15 volatile organic compounds 16 and aminoacids. 17 They have also been studied in biological membranes, [18][19][20] and in the formation of molecularly organized films using self-assembled monolayers [21][22][23] and LangmuirBlodgett (LB) [6][7][8][9][10...…”

“…Hg 2+ ions coordinated with p-tert-butylthiacalix [4]arene through the bridgingsulfur atom and its phenolic oxygen atoms, and were not located inside the calixarene cavities. 24 The presence of Cu 2+ ions in the subphase induced a shift to lower areas per molecule and a decrease in collapse pressure of tetraoxocalix [2]arene [2]triazine, with the corresponding LB films being used as voltammetric sensors to detect Cu 2+ ions. 25 Dong et al 11 produced a sensor to measure trace levels of Tl + and Cd 2+ made with an LB film of p-tertbutylthiacalix [4]arene, where the use of differential pulse stripping voltammetry led to a detection limit for Cd 2+ of 2 Â 10 À8 mol L À1 .…”

Application of Hydroxamic Modified Calix[6]arene for Selective Extraction of Uranium (VI)

“…Such functional groups include amidogen, acylamino, pyridine and Schiff base. The larger cavity in calix [6]arenes and calix [8]arenes with six and eight aromatic rings are more suitable for anchoring binding groups than calix [4]arenes. Uranium is an important radioactive element, and excessive amounts of uranium are released into the environment through activities associated with the nuclear industry and mining.…”

“…Calix[6]arene hydroxamic derivatives were synthesized by two steps using calix [6]arene, ethyl bromoacetate and hydroxylamine hydrochloride as the main raw materials, and were characterized by infrared spectroscopy. The extraction of U(VI) by calix[6]arene and its hydroxamic derivatives on various experimental conditions were studied.…”