Structure and ionic conductivity of the octahydrate of tetralithium salt of calix[4]arenesulfonic acid

Octahydrate of tetralithium salt of calix[4]sarenesulfonic acid was isolated for the first time The crystal structure of salt was determined by X-ray diffraction analysis. Compound crystallized in triclinic syngony, P-1, a=11.8752(5) A, b=12.2144(4) A, c=13.2972(6) A, α=97.241(3)o, β=99.345(4)o, γ=90.658(3)o, V=1886.96(13) A3, Z=2, R1 = 0.0407, T=150 K. The presence of 8 water molecules in the structure is confirmed by STA. According to IR spectroscopy data upon lithiation, the contours of the νs(SO3) and νas(SO3) bands become symmetric and narrower, which is explained by the disappearence of contacts between the sulfonic groups and the H5O2+ cations compared with calix[4]sarenesulfonic acid. Lithium ions are qualitatively determined from the maximum of the stretching vibration band of the Li–O bond at ~400 cm-1.The participation of H2O molecules coordinated by Li cations in the formation of a network of hydrogen bonds with oxygen atoms of sulfogroups is determined by the maximum of the stretching band ν(OH) belonging to these molecules at 3452 cm-1 in spectrum. The intense band at 3148 cm–1 refers to the ν(OH) stretching vibration of the C–OH group. The dependence of the conductivity of the tetralithium salt of calix[4]arenesulfonic acid in a wide range of humidity has been investigated. It was shown that with the gradual replacement of protons in calix[4]arenesulfonic acid, the conductivity decreases from 10-4-10-2 S/cm in acid in the ambient humidity range of 10-60 rel. % down to 10-7-10-4 S/cm for the tetralithium salt of calixarenesulfonic acid in a wide range of humidity 10-95 rel. %.