Potentiometric, ESI MS and AM1d studies of lasalocid esters-silver(I) complexes

Eight lasalocid esters (L) were synthesised and their complex formation with Ag+ cations in propylene carbonate was studied by the potentiometric, ESI MS and AM1d semiempirical methods. The stability constants of AgL+, AgL2+ and Ag2L2+ complexes were determined indicating the favourable formation of the 1:1 complexes (AgL+). ESI MS spectra of the Lasalocid esters complexes with Ag+ cations demonstrated also the formation of the 1:1 complexes. The formation of AgL2+ and Ag2L2+ complexes under the ESI MS conditions was not detected. The ΔHOF values calculated by the AM1d semiempirical method show that the formation of the 1:1 complexes is favourable and this result is in very good agreement with the experimental data. The structures of AgL+, and Ag2L2+ complexes of Las3 and Las7 are visualised and discussed.