Li-7-NMR and FTIR studies of lithium, potassium, rubidium, and cesium complexes with ionophore lasalocid in solution

Lasalocid metal salts were combined with 1 : 1 lithium and 2:2 potassium, r ubidium, and cesium to form complexes. The nature of the lasolocid salt com plexes was studied in a solid and chloroform by FTIR spectroscopy in the mi ddle and far IR regions. The process of the complexation of lithium was als o studied by Li-7-NMR. In chloroform a 1 : 1 complex of lasalocid and Li+ i ons was formed. Continuous absorption was observed in the far FTIR spectrum of this complex. It indicated large Li+ polarizability, which was due to f ast fluctuations of the Li+ ions in the multiminima potentials, in the mono meric structure. In the lasalocid salt with the other monovalent cations (K +, Rb+, Cs+) 2:2 complexes were formed in which the cations showed cation p olarizability, which strongly depended on the mass and the radius of the ca tions. (C) 2001 John Wiley & Sons, Inc.