Study of the structure of 1,3-disubstituted thiacalix[4]arenes with phthalimide and imine groups using vibrational and NMR spectroscopy

Para-tert-butylthiacalix[4]arenimines with mono- and distally substituted functional groups have been examined in terms of their structure and spectra. The structure and H-bonds of these compounds can be studied by comparing their vibrational and NMR spectra. The spectra of several conformations of the molecules TCA1-4 were calculated. For the molecules TCA3 and TCA4, the most stable conformation is a distorted cone (DC2) with the same imine or phthalimide group orientation, consequently. The least stable conformation is pinched cone (PC). The conformations of molecules TCA2, TCA3, and TCA4 are DC1 and DC2, respectively. H-bonds in the molecules TCA1-4 alter their supramolecular properties. Ionization energy and dipole moment decrease as monosubstituted thiacalixarene (TCA1) transforms into disubstituted TCA2. In this instance, there is an increase in softness, electrophilicity, chemical potential, and electron affinity. An increase in the number of methylene groups in disubstituted thiacalixarenes from TCA4 to TCA2 is accompanied by an increase in ionization energy, electron affinity, and electrophilicity.