Solution and solid-state preparation of 18-crown-6 and 15-crown-5 adducts of hydrogen sulfate salts and an investigation of the reversible dehydration processes

A new class of organic-inorganic complexes has been prepared by reaction in solution or by mechanical mixing of 15-Crown-5 or 18-Crown-6 ethers with MSO4 (M = Mn2+, Cd2+, Pb2+) and/or H2SO4 in stoichiometric amount. The complexes (15-Crown-5)[Mn(H2O)(2)(HSO4)(2)] (1), (15-Crown-5)[Cd(H2O)(2)(HSO4)(2)] (2), (15-Crown-5)[(H7O3)(HSO4)(2)]center dot H2O (3), (18-Crown-6)[Pb(HSO4)(2)] (4), and (18-Crown-6)[(H5O2)(HSO4)] (5) have been characterized by single-crystal X-ray diffraction. Compounds 1 and 2 undergo reversible water release-uptake processes, accompanied by a change in coordination at the metal centers; the dehydration and phase-transition processes have been investigated by DSC, TGA, and variable-temperature X-ray powder diffraction.