Aggregation behavior and catalytic properties of systems based on aminomethylated calix[4]resorcinarenes and poly(ethylene) imines

Influence of Solvents on Protolytic and Aggregation Properties of Aminomethylated Calix[4]resorcine

“…In a series of macrocyclic hollow systems one of the most promising objects are calix [4]resorcines characterized by the ability to molecular recognition and self-association. [1,2] They are of interest as new types of catalysts, [3][4][5][6] selective sorbents of molecules and ions, [7,8] sensors, [9] bioregulators.…”

“…[1,2] They are of interest as new types of catalysts, [3][4][5][6] selective sorbents of molecules and ions, [7,8] sensors, [9] bioregulators. [10] Earlier [11][12][13] we have described the complexing properties of aminomethylated calix [4] Depending on the solvent used (ethanol or acetone), the complexes of different composition and structure were isolated in the solid phase; but in some cases [11][12][13] complexing was not observed. We believe that this is due to the formation of associates of different -depending on the solventcompositions and structures, as a result of which the donor centers of the molecules -ligands are disabled.…”

“…Non-functionalized calix [4]resorcines are multicenter protoliths, with up to eight of acid-base centers. Previously it has been established by potentiometric titration [2,14] that the first four protons are characterized by the value рK a by two units less than the corresponding value for resorcine (рK a = 9.44); but the other four protons can not be removed even by strong bases.…”

“…The stability of the structures is due to delocalization of the negative charge, and the correct geometry of the fragments О-Н-О. [15] Aminoalkylated calix [4]resorcines are also characterized by the presence of strong intramolecular hydrogen bonds OH•••N (Figure 1c). [16] This leads to the formation of zwitter-ions within a wide range of рН = 5-10; at рН ~ 3-5 there is observed the form protonated at nitrogen atom, and at ~ рН > 10 -the phenolate one.…”

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Methods of pH-metry and quantum-chemical modeling were used to study the protolytic properties of calix [4]

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