Inclusion of aromatic and aliphatic anions into a cationic water-soluble calix[4]arene at different pH values

Encapsulation of Drug Molecules into Calix[n]arene Nanobaskets. Role of Aminocalix[n]arenes in Biopharmaceutical Field

“…In particular, comparison of 1 with 8–18 shows that attachment of just a single hydrophobic alkyl chain to the lower rim notably enhances surface activity and, as a consequence, promotes aggregation. While 1 does not show any micellization within 5 × 10 −4 to 1.5 × 10 −2 M concentration range, aqueous solutions of 8–18 aminoCAs are characterized with CMC values falling into the 10 −6 to 10 −2 M order of magnitude range with a variety of coexisting spherical objects with hydrodynamic diameters starting from 4 nm and exceeding 500 nm . However, there is no simple relationship between surface activity and aggregate size from one side and length of hydrocarbon tail from the other in 8–18 .…”

“…At certain pH values, positive and negative charges are located on the amino groups and phenolic hydroxyls, respectively, given rise to zwitter ions . For example, Sciotto and coworkers investigated the pH‐dependent characteristics of compound 1 , and proposed that it exists in its cationic form at pH 2, turns to a zwitter‐ion at neutral pH due to deprotonation of the phenolic hydroxyls (Scheme 2), whereas at weakly basic pH, deprotenation occurs and the positive charge is removed from the upper rim resulting in a notable solubility drop.…”

Binding Affinity and Driving Forces for the Interaction of Calixarene-Based Micellar Aggregates With Model Antibiotics in Neutral Aqueous Solution

“…The examination of the solution equilibria and the determination of species, binding affinity as well as thermodynamic parameters in neutral aqueous solution were carried out using nano-isothermal titration calorimetry (nano-ITC). This is an invaluable technique for determining both stability constant and enthalpy change values for host–guest complex formation (Sgarlata et al, 2009a ; Bonaccorso et al, 2012 ; Giglio et al, 2015 ) and/or self-organization of surfactants into micelles by a single experiment (Perger and Bešter-Rogač, 2007 ; De Lisi et al, 2009 ; Moulik and Mitra, 2009 ; Loh et al, 2016 ). Results from calorimetric experiments provided key information on the forces driving the molecular recognition processes involving calixarene-based micellar aggregates and model drugs in water at neutral pH.…”

Hierarchical dependence of porphyrin self-aggregation: controlling and exploiting the complexity

“…TLC was performed with silica gel 60 F254 from Macherey-Nagel. 1 H and 13 [21] were prepared according to literature procedures.…”