PHOSPHORUS-CONTAINING PODANDS. 7. COMPLEXING PROPERTIES OF ortho-DIPHENYLPHOSPHINYL-SUBSTITUTED DIPHENYL ETHERS OF OLIGOETHYLENE GLYCOLS WITH RESPECT TO ALKALI-METAL CATIONS

Article abstract of DOI:10.1007/BF00960399

Stability constants of complexes of alkali-metal cations with oligoethylene glycol diethers RO(CH2CH2O)nR (n = 1-5), where R = 2-Ph2P(O)C6H4 and 2-Ph2(O)-4-t-BuC6H3P, have been determined conductometically in a tetrahydrofuran-chloroform mixture (4:1 by volume).The dependence of complexing ability on a number of monopodand donor centers for Li⁺ and Na⁺ has multiple extrema.For K⁺, Rb⁺, and Cs⁺ the complexing abilities steadily increase with the length of the ligand polyether chain.Monopodands based on triethylene glycol and its pyrocatechol analog are highly effective (log K = 6.7-7.0) with respect to Li⁺.The synthesis of ligands with a lipophilic tert-butyl substituent in the terminal group is described.