Krafft Temperature of 1-Alkyl-4-Aza-1-Azoniabicyclo[2.2.2]octane Bromide Complexes with Transition Metal Salts

Resumo

The Krafft temperature (Т_Kr) of 1-alkyl-4-aza-1-azoniabicyclo[2.2.2]octane bromides (Alk = n-C_nH_{2n + 1}, n = 14, 16, 18) (D-n) and complexes of them with transition metals [Cu(II), Ni(II), Co(II), La(III)] in water is determined via conductometry and compared their corresponding acyclic analogs (alkyltrimethylammonium bromides). The dependence of the complexes’ Т_Kr on the structure of the inorganic salts and the hydrophobicity of ligands is established. It is shown that the complexation of D-n with metal nitrates and the shortening of the ligand hydrocarbon radical reduce Т_Kr.