Complexes of Ag+ with mixed donor phenanthroline-containing macrocycles: spectrofluorimetric, spectrophotometric, conductometric and potentiometric studies

The reactions of Ag+ with five mixed donor phenanthroline-containing macrocycles (L-1-L-5) having N2S3-, N2S2O-, N2S2-, N3S2-, and N4S2-donor sets, respectively, have been studied in MeCN by spectrofluorimetric, spectrophotometric, conductometric and potentiometric methods. All ligands form 1: 1 [Ag(L)](+) complexes, and in the case of L-4 and L-5, formation of 1:2 [Ag(L)(2)](+) species is also observed. The corresponding formation constants have been evaluated and their values allow a deeper insight into the role played by complexation process in the potentiometric selectivity for Ag+ of membrane electrodes (ISE), and in the selective transport of Ag+ through supported liquid membrane (SLM) systems based on these ligands. The X-ray crystal structure of the complex [Ag(L-4)]BF4 is also reported. (C) 2004 Elsevier B.V. All rights reserved.