FT-IR and FT-Raman study of p-sulfonatocalix [8]arene

Abstract

© 2019 Elsevier B.V. Spectral study indicates that the hydroxyl groups of calixarene are involved in the formation of intramolecular hydrogen bonds which stabilize the conformation of the pleated loop. Spectral characteristics, charge distribution, and reactivity of calix [8]arenes with tert-butyl (TB8) or sulfonate groups (SC8) were determined. From the IR data of SC8 and TB8, it follows that both substances have practically equal strong cooperative H-bonding. The torsion angles characterizing the conformation of the TB8 and SC8 molecules change. For the SC8 molecule, the pleated loop conformation is by 8.3 kcal/mol more stable than the double cone conformation. The substitution of tert-butyl groups for sulfonyl groups in calixarenes is accompanied by an increase in ionization energy, electronic affinity, chemical potential and dipole moment.