摘要:
                                Stability constants of complexes of alkali-metal cations with oligoethylene glycol diethers RO(CH2CH2O)n(R) (n = 1-5), where R = 2-Ph2P(O)C6H4 and 2-Ph2(O)-4-t-BuC6H3P, have been determined conductometrically 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.