An investigation of molecular structures of sulfonylcalix[4]arene, mercaptosulfonylcalix[4]arene and aminosulfonylcalix[4]arene, their proton affinities and complexation with zinc(II)

The geometrical structures of sulfonylcalix[4]arene, mercaptosulfonylcalix[4]arene, aminosulfonylcalix[4]arene, their complexes with zinc were obtained using density functional method at the B3LYP/6-31G(d) level of theory. The relative energies of the B3LYP/6-31G(d)-optimized structures were computed at the B3LYP/6-311G(d,p) level. The relative stabilities of the four typical conformers are in decreasing orders: partial cone>cone>1,2-alternate>1,3-alternate for sulfonylcalix[4]arene, 1,3-alternate>partial cone>1,2-alternate>cone for mercaptosulfonylcalix[4]arene and 1,3-alternate>partial cone>cone>1,2-alternate for aminosulfonylcalix[4]arene. Proton affinities of cone conformer of sulfonylcalix[4]arene, mercaptosulfonylcalix[4]arene and aminosulfonylcalix[4]arene were computed at B3LYP/6-31G(d) level of theory. The stability of zinc complexes of cone conformers of sulfonylcalix[4]arene derivatives is in decreasing order: mercaptosulfonylcalix[4]arene>sulfonylcalix[4]arene>aminosulfonylcalix[4]arene.