The role of preorganization of hydrazone moieties on tetrathiacalix[4]arene platform for their conformational and binding properties from the view of structural investigation

The IR, 1H and 13C NMR data, as well as conformation and dynamic behaviour of tetrathiacalix[4]arenes functionalized by hydrazone fragments are reported. The influence of isomers of thiacalix[4]arenes, the removal of tert-butyl groups from upper rim of macrocycle and the replacement of a phenyl substituents in the hydrazone fragments by 2-pyridyl ones on conformational properties of the compounds are discussed. The structural peculiarities of the cone isomer of 25,26,27,28-tetrakis[N2-(2-pyridinylmethylidene)hydrazinocarbonylmethyloxy]-2,8,14,20-tetrathiacalix[4]arene and the 1,3-alternate isomer of 25,26,27,28-tetrakis[N2-(benzylidene)hydrazinocarbonylmethyloxy]-2,8,14,20-tetrathiacalix[4]arene in solution are compared with their crystal structures obtained by X-ray analysis. The correlation between extraction efficiency data obtained for these compounds earlier and the conformational features of calix[4]arene hydrazone derivatives studied in this work was performed.